Glossary of research terms
Table of contents:
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A priori comparisons are planned in advance of any data analysis. They are more reliable than post-hoc comparisons.
A shortened form of a word or phrase.
Shortened forms of written words or phrases used for brevity.
Abbreviations [MeSH - publication type]: works consisting of lists of shortened forms of written words or phrases used for brevity. Acronyms are included here.
A mammalian fetus expelled by induced abortion or spontaneous abortion.
The number of abortions per 1,000 women ages 15-44 or 15-49 in a given year.
The number of abortions per 1,000 live births in a given year.
The absolute difference in rates of good or harmful outcomes between experimental groups (experimental event rate, or EER) and control groups (control event rate, or CER), calculated as the event rate in the experimental group minus the event rate in the control group (EER – CER). For instance, if the rate of adverse events is 20% in the control group and 10% in the treatment group, the absolute difference is 20% – 10% = 10%.
The inability to meet basic human needs, such as food, shelter and, avoidance of disease.
A condition characterized by severe deprivation of basic human needs, including food, safe drinking water, sanitation facilities, health, shelter, education and information. It depends not only on income but also on access to services.
The probability that an individual will experience the specified outcome during a specified period. It lies in the range 0 to 1, or is expressed as a percentage. In contrast to common usage, the word "risk" may refer to adverse events (such as myocardial infarction) or desirable events (such as cure).
The risk of an event (e.g., if 10 of 100 patients have an event, the absolute risk is 10% expressed as a percentage, or 0.10 expressed as a proportion).
The absolute arithmetic difference in rates of harmful outcomes between experimental groups (experimental event rate, or EER) and control groups (control event rate, or CER), calculated as rate of harmful outcome in experimental group minus rate of harmful outcome in control group (EER – CER). Typically used to describe a harmful exposure or intervention (e.g., if the rate of adverse outcomes is 20% in treatment and 10% in control, the absolute risk increase would be 10% expressed as a percentage and 0.10 expressed as a proportion).
Decrease in risk of a given activity or treatment in relation to a control activity or treatment.
The absolute difference (risk difference) in rates of harmful outcomes between experimental groups (experimental event rate, or EER) and control groups (control event rate, or CER), calculated as the rate of harmful outcome in the control group minus the rate of harmful outcome in the experimental group (CER – EER). Typically used to describe a beneficial exposure or intervention (e.g., if 20% of patients in the control group have an adverse event, as do 10% among treated patients, the ARR or risk difference would be 10% expressed as a percentage or 0.10 expressed as a proportion).
A brief summary of a research article, thesis, review, conference proceeding or any in-depth analysis of a particular subject or discipline.
Abstracts [MeSH - publication type]: works consisting of lists of publications on a subject and that provide full annotated bibliographical information together with substantive summaries or condensations of the facts, ideas, or opinions presented in each publication listed.
Academic clinical trials are run at academic sites, such as medical schools, academic hospitals, and universities; and non-academic sites which may be managed by so-called site management organizations. Site management organizations are for-profit organizations which enlist and manage the physician practice sites that actually recruit and follow patients enrolled in clinical trials.
Academic detailing is university or non-commercial-based educational outreach.
A strategy for changing clinician behavior. Use of a trained person who meets with professionals in their practice settings to provide information with the intent of changing their practice. The pharmaceutical industry frequently uses this strategy, to which the term detailing is applied. Academic detailing is such an interaction initiated by an academic group or institution rather than the pharmaceutical industry.
Dissertations embodying results of original research and especially substantiating a specific view, e.g., substantial papers written by candidates for an academic degree under the individual direction of a professor or papers written by undergraduates desirous of achieving honors or distinction.
Academic dissertations [MeSH - publication type]; works consisting of formal presentations made usually to fulfill requirements for an academic degree.
Degree to which a service meets the cultural needs and standards of a community. This in turn will affect utilization of that service.
A reflection of the willingness of surveillance staff to implement the system, and the end users of the data to accept and use the data generated by the system.
The perceptions and experiences of people as to their ease in reaching health services or health facilities in terms of location, time, and ease of approach.
Aspects of the structure of health services or health facilities that enhance the ability of people to reach a health care practitioner, in terms of location, time, and ease of approach.
The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.
Also called health services accessibility.
Efforts and designs to reduce the incidence of unexpected undesirable events in various environments and situations.
Obligation to demonstrate that work has been conducted in compliance with agreed rules and standards or to report fairly and accurately on performance result vis-a-vis mandated roles and/or plans. Accountability is the means used to hold persons/entities responsible for their actions.
The process by which an authorized agency or organization evaluates and recognizes an institution or an individual according to a set of “standards” describing the structures and processes that contribute to desirable patient outcomes.
Certification as complying with a standard set by non-governmental organizations, applied for by institutions, programs, and facilities on a voluntary basis.
The change in health status that would be expected to follow a specified change in the level of a risk factor, in relation to an intervention.
Also called avoidable burden of disease.
A style of research in which the researchers work with the people and for the people, rather than undertake research on them. The focus of action research is on generating solutions to problems identified by the people who are going to use the results of research.
The set of diagnoses that can plausibly explain a patient’s presentation.
The tasks of everyday life. These activities include eating, dressing, getting into or out of a bed or chair, taking a bath or shower, and using the toilet. Instrumental activities of daily living are activities related to independent living and include preparing meals, managing money, shopping, doing housework, and using a telephone. Also called ADL.
The performance of the basic activities of self care, such as dressing, ambulation, or eating.
The application of probability and statistical methods to calculate the risk of occurrence of any event, such as onset of illness, recurrent disease, hospitalization, disability, or death. It may include calculation of the anticipated money costs of such events and of the premiums necessary to provide for payment of such costs.
Hospitals with an average length of stay of 30 days or less.
Describes any trait that increases proportionately in expression when comparing those with no copy, 1 copy, or 2 copies of that allele, i.e., those with 1 copy of the allele show more of the trait than those without, and in turn, those with 2 copies show more of the trait than those with 1 copy.
A statistical model in which the combined effect of several factors is the sum of the effects produced by each of the factors in the absence of the others. For example, if one factor increases risk by a% and a second factor by b%, the additive combined effect of the two factors is (a + b)%.
Addresses [MeSH - publication type]: works consisting of speeches, orations, or written statements, usually formal, directed to a particular group of persons. These are different from lectures that are usually delivered to classes for instructional purposes.
Application of measures, technologies, and resources which are qualitatively and quantitatively sufficient for achieving the desired goal.
An analysis that controls (adjusts) for baseline imbalances in important patient characteristics.
Usually refers to attempts to control (adjust) for baseline imbalances in important patient characteristics. Sometimes used to refer to adjustments of P value to take account of multiple testing.
Term used when results have undergone statistical transformation to permit fair comparison between groups differing in some characteristic that may affect risk of disease.
A summarizing procedure in which the effects of differences in composition of the populations being compared have been minimized by statistical methods.
A person 13 to 18 years of age.
The annual number of births to women aged 15-19 years per 1,000 women in that age group. It is also referred to as the age-specific fertility rate for women aged 15-19.
Organized services to provide health care to adolescents, ages ranging from 13 through 18 years.
A medical subspecialty that focuses on care of patients who are in the adolescent period of development.
A branch of medicine pertaining to the diagnosis and treatment of diseases occurring during the period beginning with puberty until the cessation of somatic growth.
The percentage of population aged 15 years and over who can both read and write with understanding a short simple statement on his/her everyday life. Generally, ‘literacy’ also encompasses ‘numeracy’, the ability to make simple arithmetic calculations.
Probability that a 15 year old person will die before reaching his/her 60th birthday. The probability of dying between the ages of 15 and 60 years (per 1,000 population) per year among a hypothetical cohort of 100,000 people that would experience the age-specific mortality rate of the reporting year.
An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time.
In the preapproval clinical experience with a new medicinal product or its new usages, particularly as the therapeutic dose(s) may not be established, all noxious and unintended responses to a medicinal product related to any dose should be considered adverse drug reactions. The phrase "responses to a medicinal product" means that a causal relationship between a medicinal product and an adverse event is at least a reasonable possibility, i.e., the relationship cannot be ruled out. Regarding marketed medicinal products: A response to a drug that is noxious and unintended and that occurs at doses normally used in man for prophylaxis, diagnosis, or therapy of diseases or for modification of physiological function.
Also called adverse reaction.
Systems developed for collecting reports from government agencies, manufacturers, hospitals, physicians, and other sources on adverse drug reactions.
An unwanted side effect of treatment.
A harmful and undesired effect resulting from a medication or other intervention such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect, and may result from an unsuitable or incorrect dosage or procedure, which could be due to medical error.
An adverse event for which the causal relation between the drug/intervention and the event is at least a reasonable possibility. The term ‘adverse effect’ applies to all interventions, while ‘adverse drug reaction’ (ADR) is used only with drugs. In the case of drugs an adverse effect tends to be seen from the point of view of the drug and an adverse reaction is seen from the point of view of the patient.
An unexpected medical problem that happens during treatment with a drug or other therapy. Adverse events do not have to be caused by the drug or therapy, and they may be mild, moderate, or severe.
An adverse outcome that occurs during or after the use of a drug or other intervention but is not necessarily caused by it.
Advice is a statement or opinion as to how one should proceed. The purpose of advice is to influence. Advice can be based on research evidence, professional experience, personal opinion/experiences or even societal norms.
A conceptual and strategic framework that spells out goals and objectives, priority themes and key strategies to be addressed by relevant operatives at all levels. It defines, for example, an agreed vision within the context of humanitarian coordination and traces a road map of actions to be undertaken to realize this vision.
Literally, “coming to the aid of others.” Refers to the process of supporting legal, policy, or scientific positions, decisions, and arguments.
Organizations and groups that actively support participants and their families with valuable resources, including self-empowerment and survival tools.
Extent to which the intended clients of a service can pay for it.
The ratio of persons in the ages defined as dependent (under 15 years and over 64 years) to persons in the ages defined as economically productive (15-64 years) in a population.
The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from aging, a physiological process, and time factors which refers only to the passage of time.
While the phrase age of consent typically does not appear in legal statutes, when used in relation to sexual activity, the age of consent is the minimum age at which a person is considered to be legally competent of consenting to sexual acts. The European Union calls it the legal age for sexual activities.
The composition of a population as determined by the number or proportion of males and females in each age category. The age-sex structure of a population is the cumulative result of past trends in fertility, mortality, and migration. Information on age-sex composition is essential for the description and analysis of many other types of demographic data.
Mortality rate in a specific age group.
A mortality rate limited to a particular age group. The numerator is the number of deaths in that age group; the denominator is the number of persons in that age group in the population.
Age-specific rates are calculated by dividing the number of cases occurring in each specified age group by the corresponding population sampled in the same age group. Sometimes, this is expressed as a rate per 100,000 population; other times as a percent of sampled population. This rate may be calculated for a particular age and sex grouping to show how a risk factor, occurrence of death or incidence of a disease changes with age and sex. Example: Age specific current daily smoker rate for males aged 70-74 years (%) = number of male current daily smokers aged 70-74 years/ total population of males aged 70-74 years sampled x 100.
Rate obtained for specific age groups (for example, age-specific fertility rate, death rate, marriage rate, illiteracy rate, or school enrollment rate).
Rates are adjusted for age to facilitate comparisons between populations which have different age structures. (There are two different methods commonly used to adjust for age, direct and indirect. We use direct standardization in which age-specific rates are multiplied against a constant population, the WHO standard population EIP 1999).
In epidemiology and demography, age adjustment, also called age standardization, is a technique used to better allow populations to be compared when the age profiles of the populations are quite different.
The age-standardized mortality rate is a weighted average of the age-specific mortality rates per 100,000 persons, where the weights are the proportions of persons in the corresponding age groups of the WHO standard population.
Age-standardized mortality rates are used to compare the mortality rates of places without being skewed by the difference in age distributions from place to place.
Mortality rate that takes into account the age structure of the population to which it refers. Used to compare mortality in populations with very different age structures.
A mortality rate statistically modified to eliminate the effect of different age distributions in the different populations.
Also called age-adjusted mortality rate.
A factor, such as a microorganism, chemical substance, or form of radiation, whose presence, excessive presence, or (in deficiency diseases) relative absence is essential for the occurrence of a disease.
The accumulation of changes in an organism or object over time. Aging in humans refers to a multidimensional process of physical, psychological, and social change.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
A process in which the proportions of adults and elderly increase in a population, while the proportions of children and adolescents decrease. This process results in a rise in the median age of the population. Aging occurs when fertility rates decline while life expectancy remains constant or improves at the older ages.
Data summarized by groups, for example summary outcome data for treatment and control groups in a controlled trial.
The critical number of cases (or indicator, proportion, rate, etc.) that is used to sound an early warning, launch an investigation at the start of an epidemic and prepare to respond to the epidemic.
A strategy for changing clinician behavior. A type of computer decision support system that alerts the clinician to a circumstance that might require clinical action (e.g., a system that highlights out-of-range laboratory values).
An explicit description of an ordered sequence of steps with branching logic that can be applied under specific clinical circumstances. The logic of an algorithm is as follows: if a, then do x; if b, then do y; etc.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
The procedure for protecting the randomization process so that the treatment to be allocated is not known before the patient is entered into the study.
A technique used to prevent selection bias by concealing the allocation sequence from those assigning participants to intervention groups, until the moment of assignment. Allocation concealment prevents researchers from (unconsciously or otherwise) influencing which participants are assigned to a given intervention group.
The process used to ensure that the person deciding to enter a participant into a randomized controlled trial does not know the comparison group into which that individual will be allocated. This is distinct from blinding, and is aimed at preventing selection bias. Some attempts at concealing allocation are more prone to manipulation than others, and the method of allocation concealment is used as an assessment of the quality of a trial.
The ratio of intended numbers of participants in each of the comparison groups. For two group trials, the allocation ratio is usually 1:1, but unequal allocation (such as 1:2) is sometimes used.
A list of intervention groups, randomly ordered, used to assign sequentially enrolled participants to intervention groups. Also termed the "assignment schedule", "randomization schedule", or "randomization list".
With allocative efficiency, all objectives compete with each other for implementation. For example, “should we allocate more resources to the prevention of childhood injury or improve clinics for children with chronic disease such as asthma?” is a question of allocative efficiency. Allocative efficiency is about whether to do something, or how much of it to do, rather than how to do it. Allocative efficiency in health care is achieved when it is not possible to increase the overall benefits produced by the health system by reallocating resources between programs. This occurs where the ratio of marginal benefits to marginal costs is equal across all health care programs in the system.
The probability of erroneously concluding there is a difference between comparison groups when there is in fact no difference (type I error). Typically, investigators decide on the chance of a false-positive result they are willing to accept when they plan the sample size for a study (e.g., investigators often set alpha level at 0.05).
The hypothesis that the researcher is testing in the study. In scientific methodology, we start with the assumption that it is not true until proved otherwise, by rejecting the null hypothesis.
The hypothesis, to be adopted if the null hypothesis proves implausible, in which exposure is associated with disease.
All types of health services provided to patients who are not confined to an institutional bed as inpatients during the time services are rendered.
Health care services provided to patients on an ambulatory basis, rather than by admission to a hospital or other health care facility. The services may be a part of a hospital, augmenting its inpatient services, or may be provided at a free-standing facility.
Those facilities which administer health services to individuals who do not require hospitalization or institutionalization.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The aspect of epidemiology concerned with the search for health-related causes and effects. Uses comparison groups, which provide baseline data, to quantify the association between exposures and outcomes, and test hypotheses about causal relationships.
An observational study that describes associations and analyses them for possible cause and effect.
A comparative study intended to identify and quantify associations, test hypotheses, and identify causes. Two common types are cohort study and case-control study.
A short, free-standing tale narrating an interesting or amusing biographical incident.
Anecdotes [MeSH - publication type]: works consisting of brief accounts or narratives of incidents or events.
Institutional committees established to protect the welfare of animals used in research and education. The 1971 NIH Guide for the Care and Use of Laboratory Animals introduced the policy that institutions using warm-blooded animals in projects supported by NIH grants either be accredited by a recognized professional laboratory animal accrediting body or establish its own committee to evaluate animal care; the Public Health Service adopted a policy in 1979 requiring such committees; and the 1985 amendments to the Animal Welfare Act mandate review and approval of federally funded research with animals by a formally designated Institutional Animal Care and Use Committee (IACUC).
Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments, particularly model organisms such as nematode worms, fruit flies, zebrafish, and mice.
The use of animals as investigational subjects.
An animal with a disease either the same as or like a disease in humans. Animal models are used to study the development and progression of diseases and to test new treatments before they are given to humans.
Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.
A laboratory experiment using animals to study the development and progression of diseases. Animal studies also test how safe and effective new treatments are before they are tested in people.
Total number of live births expected in a specific year, for a given country, territory, or geographic area.
Total number of deaths expected in a specific year, for a given country, territory, or geographic area.
Average exponential rate of annual growth of the population over a given period.
The annual average rate of change of population size, for a given country, territory, or geographic area, during a specified period. It expresses the ratio between the annual increase in the population size and the total population for that year, usually multiplied by 100. The annual increase in the population size is defined as a sum of differences: the difference between births less deaths and the difference between immigrants less emigrants, in a given country, territory or geographic area at a given year.
Annual statements reviewing the status of the administrative and operational functions and accomplishments of an institution or organization.
Annual reports [MeSH - publication type]: works consisting of annual statements concerning the administrative and operational functions of an institution or organization.
Information which cannot be linked to the person to whom it refers, ensuring that the investigator cannot know the identity of the person and there is complete confidentiality in a study.
Testing in which the source of the specimen or the person being tested is not individually identified.
Antenatal care constitutes screening for health and socioeconomic conditions likely to increase the possibility of specific adverse pregnancy outcomes, providing therapeutic interventions known to be effective; and educating pregnant women about planning for safe birth, emergencies during pregnancy and how to deal with them.
Care provided the pregnant woman in order to prevent complications, and decrease the incidence of maternal and prenatal mortality.
Also called prenatal care.
Percentage of women who used antenatal care provided by skilled health personnel for reasons related to pregnancy at least once during pregnancy, as a percentage of live births in a given time period.
The percentage of women aged 15-49 with a live birth in a given time period that received antenatal care four or more times. Due to data limitations, it is not possible to determine the type of provider for each visit. Numerator: The number of women aged 15-49 with a live birth in a given time period that received antenatal care four or more times. Denominator: Total number of women aged 15-49 with a live birth in the same period.
The percentage of women aged 15-49 with a live birth in a given time period that received antenatal care provided by skilled health personnel (doctors, nurses, or midwives) at least once during pregnancy. Numerator: The number of women aged 15-49 with a live birth in a given time period that received antenatal care provided by skilled health personnel (doctors, nurses or midwives) at least once during pregnancy Denominator: Total number of women aged 15-49 with a live birth in the same period.
Refers to the measurement of the human individual for the purposes of understanding human physical variation.
The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.
An acronym for Acute Physiology and Chronic Health Evaluation, a scoring system using routinely collected data and providing an accurate, objective description for a broad range of intensive care unit admissions, measuring severity of illness in critically ill patients.
The application of the results from clinical trials to individual people. A randomized trial only provides direct evidence of causality within that specific trial. It takes an additional logical step to apply this result to a specific individual. Individual characteristics will affect the outcome for this person.
The degree to which the results of an observation, study or review hold true in other settings.
Any law(s) and regulation(s) addressing the conduct of clinical trials of investigational products of the jurisdiction where trial is conducted.
The application or practice of epidemiology to address public health issues.
If an expected health benefit exceeds the expected negative consequences by a large enough margin to justify performing the procedure rather than other alternatives.
In relation to institutional review boards (IRBs): the affirmative decision of the IRB that the clinical trial has been reviewed and may be conducted at the institution site within the constraints set forth by the IRB, the institution, good clinical practice (GCP), and the applicable regulatory requirements.
In the U.S., the Food and Drug Administration (FDA) must approve a substance as a drug before it can be marketed. The approval process involves several steps including pre-clinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application by the manufacturer of the drug, FDA review of the application, and FDA approval/rejection of application.
A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies.
Argument refers to a sequence of statements in which the premise purports to give reason to accept the conclusion.
In mathematics and statistics, the arithmetic mean (or simply the mean) of a list of numbers is the sum of all of the list divided by the number of items in the list. If the list is a statistical population, then the mean of that population is called a population mean. If the list is a statistical sample, we call the resulting statistic a sample mean.
The measure of central location commonly called the average. It is calculated by adding together all the individual values in a group of measurements and dividing by the number of values in the group.
In a controlled trial refers to a group of participants allocated a particular treatment. In a randomized controlled trial, allocation to different arms is determined by the randomization procedure. Many controlled trials have two arms, a group of participants assigned to an experimental intervention (sometimes called the treatment arm) and a group of participants assigned to a control (the control arm). Trials may have more than two arms, with more than one experimental arm and/or more than one control arm.
Systematic distortion of the results of a randomized trial as a result of knowledge of the group assignment by the person assessing outcome, whether an investigator or the participant themselves.
A systematic or non-systematic way of gathering relevant information, analyzing and making judgment on the basis of the available information.
The process in an experiment where the researcher allocates subjects to two or more groups, trying to achieve having groups as identical as possible to allow a valid comparison of the results. Matching and random assignment are the two most common methods.
All treatments or procedures that include the in vitro handling of both human oocytes and sperm, or embryos, for the purpose of establishing a pregnancy. This includes, but is not limited to, in vitro fertilization and embryo transfer, gamete intrafallopian transfer, zygote intrafallopian transfer, tubal embryo transfer, gamete and embryo cryopreservation, oocyte and embryo donation, and gestational surrogacy. Assisted reproductive technology (ART) does not include assisted insemination (artificial insemination) using sperm from either a woman's partner or a sperm donor.
Clinical and laboratory techniques used to enhance fertility in humans and animals.
Also called assisted reproductive technics.
A relationship between two characteristics, such that as one changes, the other changes in a predictable way. For example, statistics demonstrate that there is an association between smoking and lung cancer. In a positive association, one quantity increases as the other one increases (as with smoking and lung cancer). In a negative association, an increase in one quantity corresponds to a decrease in the other. Association does not necessarily imply a causal effect. (Also called correlation.)
Statistical relationship between two or more events, characteristics, or other variables.
A collection of maps.
Atlases [MeSH - publication type]: works consisting of collections of illustrative plates, charts, etc., usually with explanatory captions.
In epidemiology, an attack rate is the cumulative incidence of infection in a group of people observed over a period of time during an epidemic, usually in relation to foodborne illness. The term is defined as the number of exposed persons infected with the disease divided by the total number of exposed persons. It is measured from the beginning of an outbreak to the end of the outbreak.
A variant of an incident rate, applied to a narrowly defined population observed for a limited period of time, such as during an epidemic.
The amount of ill health that can be attributed to a particular risk factor.
A measure of the public health impact of a causative factor; proportion of a disease in a group that is exposed to a particular factor which can be attributed to their exposure to that factor.
An estimate to quantify the contribution which a particular risk factor makes in producing the disease within a population.
The loss of participants during the course of a study. (Also called loss to follow up.) Participants that are lost during the study are often call dropouts.
Systematic differences between comparison groups in withdrawals or exclusions of participants from the results of a study. For example, participants may drop out of a study because of side effects of an intervention, and excluding these participants from the analysis could result in an overestimate of the effectiveness of the intervention, especially when the proportion dropping out varies by treatment group.
A systematic and independent examination of trial-related activities and documents to determine whether the evaluated trial-related activities were conducted, and the data were recorded, analyzed, and accurately reported according to the protocol, sponsor's standard operating procedures (SOPs), good clinical practice (GCP), and the applicable regulatory requirement(s).
A declaration of confirmation by the auditor that an audit has taken place.
A written evaluation by the sponsor's auditor of the results of the audit.
Documentation that allows reconstruction of the course of events.
Occurs when the likelihood of an observation is not independent of its relationship with other observations. For example, autocorrelation occurs when a good day for a patient with chronic disease is more likely to follow a "good day" than a "bad day."
Literally, self ruling. Related to, and sometimes used in lieu of the bioethical principle of respect for persons. Implies intentionality and freedom from coercion. In the Kantian tradition, autonomy implies freely embracing a moral obligation. In public health, individual autonomy may be limited by interventions applied to populations.
Identifies the presence or absence of needed health care services.
A measure for the central tendency of a sample of observations. The term average is most often used for the arithmetic mean, but sometimes also for the median. For instance, suppose the yearly income of five people is $50,000, $80,000, $100,000, $120,000, and $650,000. The arithmetic mean is the sum of these values divided by their number, that is, $200,000. The median is obtained by ranking the values (as above) and taking the one in the middle, that is, $100,000. When the distribution is asymmetric, as it is often with income, the mean and the median are not the same, and it can be the case that most people earn less than the mean.
The cost per unit of output. Each of the three cost concepts discussed above can be expressed as an average cost: average fixed costs, average variable costs and average total costs, by dividing cost by the measure of output (patient days, hospital admissions, diagnostic tests performed, etc).
Average length of stay is computed by dividing the (total) number of days in inpatient or acute care institutions by the number of discharges (or admissions). Table of contents:
A basic demographic formula used to estimate total population change between two points in time — or to estimate any unknown component of population change, provided that the other components are known. The balancing equation includes all components of population change: births, deaths, immigration, emigration, in-migration, and out-migration.
A graphic method of describing the data, where the frequency of a particular category is reflected in the height of the bar in the graph.
A visual display of the size of the different categories of a variable. Each category or value of the variable is represented by a bar.
Information gathered at the beginning of a study from which variations found in the study are measured.
A known value or quantity with which an unknown is compared when measured or assessed.
The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.
An initial measurement that is taken at an early time point to represent a beginning condition, and is used for comparison over time to look for changes. For example, the size of a tumor will be measured before treatment (baseline) and then afterwards to see if the treatment had an effect.
A phase in an intervention study where the participants have not received any intervention.
An observation or value that represents the background level of a measurable quantity.
Is an assessment performed during the design phase of a surveillance plan of action. It provides information on the existing situation, forms the basis for the development of the plan of action, and provides baseline data against which prospective changes in the surveillance system are progressively assessed or measured.
Values of demographic, clinical and other variables collected for each participant at the beginning of a trial, before the intervention is administered.
Data or measurements collected at the outset of implementation of a surveillance system or of strengthening activities, or a set of indicators that have been identified to monitor and evaluate the performance of a surveillance and response system. For example, the baseline mortality rate (or non-crisis mortality rate) is mortality rate before the crisis.
The proportion or percentage of study participants in the control group in whom an adverse outcome is observed.
In epidemiology, the basic reproduction number (sometimes called basic reproductive rate or basic reproductive ratio) of an infection is the mean number of secondary cases a typical single infected case will cause in a population with no immunity to the disease in the absence of interventions to control the infection.
The expected number of new cases of an infection caused by an infected individual, in a population consisting of susceptible contacts only.
An expression of the likelihood that a particular event will occur within a particular population.
A probability theorem used to update the probability of an event in the light of a piece of new evidence. A common application is in diagnosis, where the prior probability of disease, obtained from population data, is updated to a posterior probability in the light of a positive or negative result from a diagnostic test.
A theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihoods of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result.
Approaches to data analysis that provide a posterior probability distribution for some parameter (e.g. treatment effect), derived from the observed data and a prior probability distribution for the parameter. The posterior distribution is then used as the basis for statistical inference.
An approach to statistics based on application of Bayes’ theorem that can be used in single studies or meta-analysis. A Bayesian analysis uses Bayes' theorem to transform a prior distribution for an unknown quantity (e.g. an odds ratio) into a posterior distribution for the same quantity, in light of the results of a study or studies. The prior distribution may be based on external evidence, common sense or subjective opinion. Statistical inferences are made by extracting information from the posterior distribution, and may be presented as point estimates, and credible intervals (the Bayesian equivalent of confidence intervals).
The reallocation of beds from one type of care service to another, as in converting acute care beds to long term care beds.
A day during which a person is confined to a bed and in which the patient stays overnight in a hospital.
A measure of inpatient health facility use based upon the average number or proportion of beds occupied for a given period of time.
A method of control in which results from experimental subjects are compared with outcomes from patients treated before the new intervention was available. These are called historic controls.
Research that involves the application of the behavioral and social sciences to the study of the actions or reactions of persons or animals in response to external or internal stimuli.
The characteristic shape of the curve of a normal distribution, where the data are equally distributed around the mean.
Reference point or standard against which performance or achievements can be assessed. A benchmark refers to the performance that has been achieved in the recent past by other comparable organizations, or what can be reasonably inferred to have been achieved in the circumstances.
A process of measuring another organization’s product or service according to specified standards in order to compare it with and improve one’s own product or service.
Method of measuring performance against established standards of best practice.
An ethical principle implying that every effort should be made to maximize the benefits to the subjects in health research.
Literally, doing good; in bioethics, a prima facie principle underlying utilitarian approaches. Implies an obligation to promote benefits of things judged to be good, typically balancing produced goods against risks or harms. In public health, beneficence implies acting in the best interest of the population or society as a whole.
The state or quality of being kind, charitable, or beneficial.
Benefits are potential favorable effects on health or its determinants, whether or not intended by a proposal.
Systematic reviews of RCTs are the best method for revealing the effects of a therapeutic intervention.
In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with the best practice. Also called standard therapy or standard of care.
Best practice(s) refer(s) to interventions that are supposed to lead to desired outcomes.
In a scientific research study or clinical trial, a flaw in the study design or the method of collecting or interpreting information. Biases can lead to incorrect conclusions about what the study or clinical trial showed.
When a point of view prevents impartial judgment on issues relating to the subject of that point of view. In clinical studies, bias is controlled by blinding and randomization
The systematic tendency of any factors associated with the design, conduct, analysis and evaluation of the results of a clinical trial to make the estimate of a treatment effect deviate from its true value. Bias introduced through deviations in conduct is referred to as 'operational' bias. The other sources of bias listed above are referred to as 'statistical'.
In statistics: a systematic error or deviation in results or inferences from the truth. In studies of the effects of health care, the main types of bias arise from systematic differences in the groups that are compared (selection bias), the care that is provided, exposure to other factors apart from the intervention of interest (performance bias), withdrawals or exclusions of people entered into a study (attrition bias) or how outcomes are assessed (detection bias). Reviews of studies may also be particularly affected by reporting bias, where a biased subset of all the relevant data is available.
Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.
Aspects of the design or conduct of a study designed to prevent bias. For controlled trials, such aspects include randomization, blinding and concealment of allocation.
A database of bibliographic records.
Extensive collections, reputedly complete, of references and citations to books, articles, publications, etc., generally on a single subject or specialized subject area. Databases can operate through automated files, libraries, or computer disks. The concept should be differentiated from databases, factual which is used for collections of data and facts apart from bibliographic references to them.
A list of books, articles, documents, publications, and other items, usually on a single subject or related subjects.
Discussion of lists of works, documents or other publications, usually with some relationship between them, e.g., by a given author, on a given subject, or published in a given place, and differing from a catalog in that its contents are restricted to holdings of a single collection, library, or group of libraries.
Bibliography [MeSH - publication type]: a work consisting of a list of books, articles, documents, publications, and other items, usually on a single subject or related subjects.
A statistical distribution with known properties describing the number of occurrences of an event in a series of observations. Thus, the number of deaths in the control arm of a controlled trial follows a binomial distribution. The distribution forms the basis for analyses of dichotomous data.
The probability distribution associated with two mutually exclusive outcomes; used to model cumulative incidence rates and prevalence rates. The Bernoulli distribution is a special case of binomial distribution.
The ability of a drug or other substance to be absorbed and used by the body. Orally bioavailable means that a drug or other substance that is taken by mouth can be absorbed and used by the body.
A biography which includes a list of the writings of the subject person.
Biobibliography [MeSH - publication type]: works consisting of biographical information as well as lists of the writings of those persons.
A pregnancy diagnosed only by the detection of HCG in serum or urine and that does not develop into a clinical pregnancy.
Also called preclinical spontaneous abortion/miscarriage.
Clusters of topics that fall within the domain of bioethics, the field of study concerned with value questions that arise in biomedicine and health care delivery.
Bioethics is the philosophical study of the ethical controversies brought about by advances in biology and medicine. Bioethicists are concerned with the ethical questions that arise in the relationships among life sciences, biotechnology, medicine, politics, law, philosophy, and theology.
A field of inquiry and academic discipline at the intersection of ethics and the life sciences. Emerging with an emphasis upon problems faced in the practice of medicine and biomedical research, bioethics has overlapping areas of scholarship and application: theory and method, clinical practice, regulatory policy, research practice, cultural and social concerns,8 and recently, public health and epidemiology.
A branch of applied ethics that studies the value implications of practices and developments in life sciences, medicine, and health care.
A written account of a person's life and the branch of literature concerned with the lives of people.
Biography [MeSH - publication type]: works consisting of an account of the events, works, and achievements, personal and professional, during a person's life. It includes articles on the activities and accomplishments of living persons as well as the presentation of an obituary.
The science of using computers, databases, and math to organize and analyze large amounts of biological, medical, and health information. Information may come from many sources, including patient statistics, tissue specimens, genetics research, and clinical trials.
A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories applicable to molecular biology and areas of computer-based techniques for solving biological problems including manipulation of models and datasets.
Also called computational biology.
The indirect vector-borne transmission of an infectious agent in which the agent undergoes biologic changes within the vector before being transmitted to a new host.
The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.
A substance that is made from a living organism or its products and is used in the prevention, diagnosis, or treatment diseases. Biological drugs include antibodies, interleukins, and vaccines. Also called biologic agent or biological agent.
A biomarker, or biological marker, is in general a substance used as an indicator of a biological state. It is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
Biological plausibility means that the relation makes sense according to the prevailing understanding of pathobiological processes.
Biomedical research (or experimental medicine), in general simply known as medical research, is the basic research, applied research, or translational research conducted to aid and support the body of knowledge in the field of medicine.
Research that involves the application of the natural sciences, especially biology and physiology, to medicine.
A method of differentiating individuals based on the analysis of qualitative or quantitative biological traits or patterns. This process which has applications in forensics and identity theft prevention includes DNA profiles or DNA fingerprints, hand fingerprints, automated facial recognition, iris scan, hand geometry, retinal scan, vascular patterns, automated voice pattern recognition, and ultrasound of fingers.
The science of collecting and analyzing biologic or health data using statistical methods. Biometrics may be used to help learn the possible causes of a disease in a certain group of people. Also called biostatistics and biometry.
The science of collecting and analyzing biologic or health data using statistical methods. Biometry may be used to help learn the possible causes of a disease in a certain group of people. Also called biostatistics and biometrics.
The use of statistical and mathematical methods to analyze biological observations and phenomena.
The science of collecting and analyzing biologic or health data using statistical methods. Biostatistics may be used to help learn the possible causes of a disease in a certain group of people. Also called biometry and biometrics.
The application of statistics to biological systems and organisms involving the retrieval or collection, analysis, reduction, and interpretation of qualitative and quantitative data.
Any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use.
Body of knowledge related to the use of organisms, cells or cell-derived constituents for the purpose of developing products which are technically, scientifically and clinically useful. Alteration of biologic function at the molecular level (i.e., genetic engineering) is a central focus; laboratory methods used include transfection and cloning technologies, sequence and structure analysis algorithms, computer databases, and gene and protein structure function analysis and prediction.
A regimen of one or more actions, devices, sexual practices, or medications followed in order to deliberately prevent or reduce the likelihood of pregnancy or childbirth.
Practices employed by couples that permit sexual intercourse with reduced likelihood of conception and birth. The term birth control is often used synonymously with such terms as contraception, fertility control, and family planning. But birth control includes abortion to prevent a birth, whereas family planning methods explicitly do not include abortion.
Elapsed time between a mother’s deliveries. This is sometimes calculated as the time from delivery to the last menstrual period (LMP) of the subsequent pregnancy (called “inter-pregnancy interval”) to avoid confounding by length of the subsequent pregnancy.
The lengths of intervals between births to women in the population.
The number of births in a given population per year or other unit of time.
The number of live births per 1,000 unmarried women (never married, widowed, or divorced) ages 15-49 in a given year.
Birth weight is the first weight of the fetus or newborn obtained after birth. For live births, birth weight should ideally be measured within the first hour of life before significant postnatal weight loss occurs.
Weight of the baby (live born or stillborn) at delivery.
The mass or quantity of heaviness of an individual at BIRTH. It is expressed by units of pounds or kilograms.
Percentage of live births attended by skilled health personnel in a given period of time.
Percentage of births by caesarean section among all live births in a given time period.
A randomized trial is "Blind" if the participant is not told which arm of the trial he is on. A clinical trial is "Blind" if participants are unaware on whether they are in the experimental or control arm of the study; also called masked.
A procedure in which one or more parties to the trial are kept unaware of the treatment assignment(s). Single blinding usually refers to the subject(s) being unaware, and double blinding usually refers to the subject(s), investigator(s), monitor, and, in some cases, data analyst(s) being unaware of the treatment assignment(s).
The evaluation of an outcome is made without the evaluator knowing which results are from the test under study and which are from the control or “gold standard”.
The checking and assessment of data during the period of time between trial completion (the last observation on the last subject) and the breaking of the blind, for the purpose of finalizing the planned analysis.
Medical journals: one common review process is the same as the peer review, except all references to the authors are removed from the article before review by the researchers. This has been particularly important in medical research as there is a strong bias against articles produced by non-physicians, which are more likely to get rejected.
A type of study in which the patients (single-blinded) or the patients and their doctors (double-blinded) do not know which drug or treatment is being given. The opposite of a blinded study is an open label study.
In a controlled trial: the process of preventing those involved in a trial from knowing to which comparison group a particular participant belongs. The risk of bias is minimized when as few people as possible know who is receiving the experimental intervention and who the control intervention. Participants, caregivers, outcome assessors, and analysts are all candidates for being blinded. Blinding of certain groups is not always possible, for example surgeons in surgical trials. The terms single blind, double blind and triple blind are in common use, but are not used consistently and so are ambiguous unless the specific people who are blinded are listed. (Also called masking.)
Randomization by a pattern to produce the required number of people in each group.
Book reviews [MeSH - publication type]: works consisting of critical analyses of books or other monographic works.
Words used when searching electronic databases. These operators are AND, OR, and NOT and are used to combine terms (AND/OR) or exclude terms (NOT) from the search strategy.
Booster sessions are refresher sessions of the main content of formerly conducted interventions (i.e. school-based prevention programs).
A visual display that summarizes data using a ``box and whiskers format to show the minimum and maximum values (ends of the whiskers), interquartile range (length of the box), and median (line through the box).
A statement of the financial resources made available to provide an agreed level of service over a set period of time or to use them for a specific purpose.
Detailed financial plans for carrying out specific activities for a certain period of time. They include proposed income and expenditures.
The burden of disease is a measurement of the gap between a population's current health and the optimal state where all people attain full life expectancy without suffering major ill-health.
Refers to the overall impact of diseases and injuries at the individual level, at the societal level, or to the economic costs of diseases.
The total quantity of ill health caused by a particular disease or risk factor.
The burden of proof in public health determines how evidence based practice is interpreted and applied.
Table of contents:
The average nutritional energy content of the total daily per capita food supply, for a given country, territory, or geographic area, over a specific period in time, usually a year.
Capacity building is the development of knowledge, skills, commitment, structures, systems and leadership to enable effective health promotion. It involves actions to improve health at three levels: the advancement of knowledge and skills among practitioners; the expansion of support and infrastructure for health promotion in organizations, and; the development of cohesiveness and partnerships for health in communities.
Organizational development including enhancement of management structures, processes and procedures, within organizations and among different organizations and sectors to meet present and future needs.
The expenditure that is required for financing permanent or semi-permanent facilities or equipment, such as buildings etc.
Those funds disbursed for facilities and equipment, particularly those related to the delivery of health care.
Carer (UK, NZ, Australian usage) and caregiver (US, Canadian usage) are words normally used to refer to unpaid relatives or friends who support people with disabilities. The words may be prefixed with "family" "spousal", "child" to distinguish between different care situations.
Persons who provide care to those who need supervision or assistance in illness or disability. They may provide the care in the home, in a hospital, or in an institution. Although caregivers include trained medical, nursing, and other health personnel, the concept also refers to parents, spouses, or other family members, friends, members of the clergy, teachers, social workers, fellow patients, etc.
In a cross-over trial: the persistence, into a later period of treatment, of some of the effects of a treatment applied in an earlier period.
In epidemiology, a countable instance in the population or study group of a particular disease, health disorder, or condition under investigation. Sometimes, an individual with the particular disease.
A type of observational analytical longitudinal retrospective study in which a group of subjects with a specified outcome (cases) and a group without that outcome (controls) are identified. Investigators then compare the extent to which each subject was previously exposed to the variable of interest, such as risk factor, a treatment, or an intervention.
A type of observational analytic study. Enrollment into the study is based on presence ("case) or absence ("control) of disease. Characteristics such as previous exposure are then compared between cases and controls.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
Is a set of diagnostic criteria that must be fulfilled in order to identify a case of a particular disease. Case definitions can be based on clinical, laboratory, epidemiological, or combined clinical and laboratory criteria. When a set of criteria is standardized for purposes of identifying a particular disease, then it is referred to as "standard case definition". A surveillance case definition is one that is standardized and used to obtain an accurate detection of all cases of the targeted disease or condition in a given population, while excluding the detection of other similar conditions.
A set of standard criteria for deciding whether a person has a particular disease or health-related condition, by specifying clinical criteria and limitations on time, place, and person.
The proportion of cases of a given disease that result in death. Often abbreviated to CFR.
In epidemiology, case fatality (CF) or fatality rate, is the ratio of deaths within a designated population of people with a particular condition, over a certain period of time. An example of a fatality rate would be 9 deaths per 10,000 people at risk per year. This means that within a given year, out of 10,000 people formally diagnosed with a disease, 9 died.
A traditional term for all the activities which a physician or other health care professional normally performs to insure the coordination of the medical services required by a patient. It also, when used in connection with managed care, covers all the activities of evaluating the patient, planning treatment, referral, and follow-up so that care is continuous and comprehensive and payment for the care is obtained.
The composition of patients treated by a hospital or another provider.
The number of reported cases of a specific disease per 100,000 population in a given year.
A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).
Case reports [MeSH - publication type]: clinical presentations that may be followed by evaluative studies that eventually lead to a diagnosis.
A printed, optical, or electronic document designed to record all of the protocol-required information to be reported to the sponsor on each trial subject.
A group or series of case reports involving patients who were given similar treatment. Reports of case series usually contain detailed information about the individual patients. This includes demographic information (for example, age, gender, ethnic origin) and information on diagnosis, treatment, response to treatment, and follow-up after treatment.
A study reporting observations on a series of individuals, usually all receiving the same intervention, with no control group.
A study reporting observations on a single individual. (Also called anecdote, case history, or single case report.)
A detailed description of a concrete situation requiring ethical analysis and a resultant judgment or action. Cases provide specific circumstances involving a patient (in medical ethics), a study participant or group (in research ethics) or a population (in public health ethics). Cases are typically grouped by subject matter and as such represent the input to the methods of practical ethical reasoning.
A method of practical ethical reasoning emphasizing particular cases over theories or principles. From paradigm cases and the selection of morally relevant maxims indicating the right judgment or action, the user of casuistry finds generalizable guidance for judgments and actions when confronted with similar cases. Casuistry is not incompatible with the methods of principlism and specified principlism.
A method of ethical analysis that emphasizes practical problem solving through examining individual cases that are considered to be representative; sometimes used to denote specious argument or rationalization. Differentiate from casuistics, which is the recording and study of cases and disease.
A geographic area defined and served by a health plan or a health care provider.
A geographic area defined and served by a health program or institution.
Estimate of the population served by a hospital or other health service unit or facility.
Data that are classified into two or more non-overlapping categories. Race and type of drug (aspirin, paracetamol, etc.) are examples of categorical variables. If there is a natural order to the categories, for example, non-smokers, ex-smokers, light smokers and heavy smokers, the data are known as ordinal data. If there are only two categories, the data are dichotomous data.
Data where each individual variable is one of a number of mutually exclusive classes.
An association between two characteristics that can be demonstrated to be due to cause and effect, i.e. a change in one causes the change in the other. Causality can be demonstrated by experimental studies such as controlled trials (for example, that an experimental intervention causes a reduction in mortality). However, causality can often not be determined from an observational study.
The relating of causes to the effects they produce. Most of epidemiology concerns causality and several types of causes can be distinguished. It must be emphasized, however, that epidemiological evidence by itself is insufficient to establish causality, although it can provide powerful circumstantial evidence.
Causality is the relating of causes to the effects they produce. Broadly, causality is about production in the sense that a cause is something that produces or creates an effect. Causality is fundamental to two aspects of evidence based public health: (1) demonstrating and understanding the causes of public health problems; and (2) establishing the probability and nature of causal relations between an intervention and its effects.
The relating of causes to the effects they produce. Causes are termed necessary when they must always precede an effect and sufficient when they initiate or produce an effect. Any of several factors may be associated with the potential disease causation or outcome, including predisposing factors, enabling factors, precipitating factors, reinforcing factors, and risk factors.
Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint.
A factor (characteristic, behavior, event, etc.) that directly influences the occurrence of disease. A reduction of the factor in the population should lead to a reduction in the occurrence of disease.
The mortality rate due to a specific disease (e.g. cholera) or phenomenon (e.g. violence).
The number of deaths attributable to a specific cause per 100,000 population in a given year.
The mortality rate from a specified cause for a population. The numerator is the number of deaths attributed to a specific cause during a specified time interval; the denominator is the size of the population at the midpoint of the time interval.
Also called cause-specific death rate.
The causes of death are those that are entered on the medical certificate of cause of death in countries and recorded by the civil (vital) registration systems. For the analyses, we have used the concept of the 'underlying cause of death' as defined by ICD (WHO, 1992). In countries with incomplete or no civil registration, causes of death are those reported as such in epidemiological studies that use verbal autopsy algorithms to establish cause of death.
In survival analysis: a term used in studies where the outcome is the time to a particular event, to describe data from patients where the outcome is unknown. A patient might be known not to have had the event only up to a particular point in time, so ‘survival time’ is censored at this point.
A census is the procedure of systematically acquiring and recording information about the members of a given population.
A canvass of a given area, resulting in an enumeration of the entire population and often the compilation of other demographic, social, and economic information pertaining to that population at a specific time.
The enumeration of an entire population, usually with details being recorded on residence, age, sex, occupation, ethnic group, marital status, birth history, and relationship to head of household.
Enumerations of populations usually recording identities of all persons in every place of residence with age or date of birth, sex, occupation, national origin, language, marital status, income, relation to head of household, information on the dwelling place, education, literacy, health-related data (e.g., permanent disability), etc. The census or "numbering of the people" is mentioned several times in the Old Testament. Among the Romans, censuses were intimately connected with the enumeration of troops before and after battle and probably a military necessity.
The average (mean), middle (median) or most common (mode) score for numerical data in a frequency distribution.
Compliance with a set of standards defined by non-governmental organizations. Certification is applied for by individuals on a voluntary basis and represents a professional status when achieved, e.g., certification for a medical specialty.
Tendency of clinicians to prescribe treatment based on a patient’s prognosis. As a result of the behavior, in observational studies, treated patients are more or less likely to be high-risk patients than untreated patients, leading to biased estimate of treatment effect.
A type of informational job aid used to reduce failure by compensating for potential limits of human memory and attention.
Aid for consistent recording of data such as tasks completed and observations noted.
The effect on clinicians’ behavior of having them record information, or their orders, using a structured data collection form.
The improvement seen in medical decision making because of more complete and structured data collection (e.g., clinicians fill out a detailed form, so their decisions improve).
A statistical test used for categorical data. It is based on a comparison of the frequencies observed and the frequencies expected in the various categories.
A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.
A person 6 to 12 years of age. An individual 2 to 5 years old is child, preschool.
Organized services to provide health care for children.
Number of deaths of children between one year of age to 12 years of age in a given population.
The probability of a child born in a specific year or period dying before reaching the age of five, if subject to age-specific mortality rates of that period. Under-five mortality rate as defined here is strictly speaking not a rate (i.e. the number of deaths divided by the number of population at risk during a certain period of time) but a probability of death derived from a life table and expressed as rate per 1,000 live births.
The child mortality rate or under-5 mortality rate is the number of children who die by the age of five, per thousand live births.
The number of children under five years of age dying per 1,000 live births in a given year.
Also called under-five mortality rate.
The number of children under age 5 per 1,000 women ages 15-44 or 15-49 in a population in a given year. This crude fertility measure, based on basic census data, is sometimes used when more specific fertility information is not available.
The reproductive age span of women, assumed for statistical purposes to be 15-44 or 15-49 years of age.
The process of giving birth to one or more offspring.
Also called birth, parturition.
Childlessness (demographic studies): inability to bear any children, either due to the inability to conceive or the inability to carry a pregnancy to a live birth. Childlessness at the end of the reproductive years is most effectively studied by using women in the oldest age cohort: women 45 to 49 years.
Percentage of women who are currently married, have been so for at least five years, and who have no living children.
Percentage of overweight (weight-for-height above +2 standard deviations of the WHO Child Growth Standards median) among children aged 0-5 years.
Percentage of stunting (height-for-age less than -2 standard deviations of the WHO Child Growth Standards median) among children aged 0-5 years.
Percentage of underweight (weight-for-age less than -2 standard deviations of the WHO Child Growth Standards median) among children aged 0-5 years.
The temporal sequence of events that have occurred.
Chronology [MeSH - publication type]: works consisting of lists of events arranged in chronological order.
Civil defense or civil protection is an effort to prepare non-combatants for military attack.
Preventive emergency measures and programs designed to protect the individual or community in times of hostile attack.
A span of values of a continuous variable which are grouped into a single category for a frequency distribution of that variable.
Classical article [MeSH - publication type]: works consisting of a current presentation of a previously printed seminal article marking a milestone in the history of medicine or science. It is usually accompanied by introductory remarks heralding its reprinting, often on the anniversary of its original publication or on an anniversary of the author's birth or death. It is usually reprinted in full, with complete bibliographical reference to the original appearance.
Pertaining to or founded on observation and treatment of participants, as distinguished from theoretical or basic science.
A cyclical evaluation and measurement by health professionals of the clinical standards they are achieving.
A detailed review and evaluation of selected clinical records by qualified professional personnel to improve the quality of patient care and outcomes. The clinical audit was formally introduced in 1993 into the United Kingdom's National Health Service.
A clinical coder, also known as diagnostic coder or medical coder, is a health care professional whose main duties are to analyse clinical statements and assign codes from a clinical classification.
Clinical conference [MeSH: publication type]: work that consists of a conference of physicians on their observations of a patient at the bedside, regarding the physical state, laboratory and other diagnostic findings, clinical manifestations, results of current therapy, etc. A clinical conference usually ends with a confirmation or correction of clinical findings by a pathological diagnosis performed by a pathologist. "Clinical conference" is often referred to as a "clinico-pathological conference."
Acquisition or collection of clinical trial data can be achieved through various methods that may include, but are not limited to, any of the following: paper or electronic medical records, paper forms completed at a site, interactive voice response systems, local electronic data capture systems, or central web based systems.
Clinical decision support systems (CDSS or CDS) are interactive computer programs, which are designed to assist physicians and other health professionals with decision making tasks. Clinical decision support systems link health observations with health knowledge to influence health choices by clinicians for improved health care.
A strategy for changing clinician behavior. An information system used to integrate clinical and patient information and provide support for decision-making in patient care.
Computer-based information systems used to integrate clinical and patient information and provide support for decision-making in patient care.
The extent to which a specific intervention, procedure, regimen or service does what it is intended to do under ordinary circumstances rather than controlled conditions. Or, more specifically, the evaluation of benefit to risk of an intervention, in a standard clinical setting, using outcomes measuring issues of importance to patients (e.g. ability to do daily activities, longer life, etc.).
The identification, analysis, and resolution of moral problems that arise in the care of patients.
Hospital or other institutional ethics committees established to consider the ethical dimensions of patient care. Distinguish from ethics committees, research, which are established to monitor the welfare of patients or healthy volunteers participating in research studies.
The physician's overall intuitive sense of the likelihood of disease established after the clinical evaluation of the patient. The clinical evaluation may include risk factors, history, symptoms, signs, and basic laboratory or radiological studies.
Clinical governance is the term used to describe a systematic approach to maintaining and improving the quality of patient care within a health system.
A framework through which the United Kingdom's National Health Service organizations are accountable for continually improving the quality of their services and safeguarding high standards of care by creating an environment in which excellence in clinical care will flourish.
A systematically developed statement for practitioners and participants about appropriate health care for specific clinical circumstances.
Any experiment that involves a test article and one or more human subjects.
A medical researcher in charge of carrying out a clinical trial's protocol.
The study and practice of medicine by direct examination of the patient.
Oversight and administrative efforts that monitor a participant's health during a clinical trial.
Research carried out by nurses in the clinical setting and designed to provide information that will help improve patient care. Other professional staff may also participate in the research.
Measures patient health or well being. Ideally it should be credible, comprehensive, sensitive to change, accurate, sensible, and biologically sensible.
Clinical pathways, also known as care pathways, critical pathways, integrated care pathways, or care maps, are one of the main tools used to manage the quality in healthcare concerning the standardization of care processes.
Multidisciplinary management tool based on evidence-based practice for a specific group of patients with a predictable clinical course, in which the different tasks (interventions) by the professionals involved in the patient care are defined, optimized and sequenced either by hour (ED), day (acute care) or visit (homecare). Outcomes are tied to specific interventions.
Schedules of medical and nursing procedures, including diagnostic tests, medications, and consultations designed to effect an efficient, coordinated program of treatment.
Guideline developed to help health care professionals and patients make decisions about screening, prevention, or treatment of a specific health condition.
A strategy for changing clinician behavior. Systematically developed statements or recommendations to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances. They present indications for performing a test, procedure, or intervention, or the proper management for specific clinical problems. Guidelines may be developed by government agencies, institutions, organizations such as professional societies or governing boards, or by convening expert panels.
A systematically developed statement to assist practitioner and patient decisions about appropriate health care for one or more specific clinical circumstances. The development of clinical practice guidelines can be considered to be a particular type of health technology assessment (HTA) or it can be considered to be one of the types of policy-making that is informed or supported by HTA.
A clinical prediction rule is type of medical research study in which researchers try to identify the best combination of medical sign, symptoms, and other findings in predicting the probability of a specific disease or outcome.
A guide for practice that is generated by initially examining, and ultimately combining, a number of variables to predict the likelihood of a current diagnosis or a future event. Sometimes, if the likelihood is sufficiently high or low, the rule generates a suggested course of action.
A pregnancy diagnosed by ultrasonographic visualization of one or more gestational sacs or definitive clinical signs of pregnancy. It includes ectopic pregnancy. Note: multiple gestational sacs are counted as one clinical pregnancy.
The number of clinical pregnancies expressed per 100 initiated cycles, aspiration cycles or embryo transfer cycles. Note: when clinical pregnancy rates are given, the denominator (initiated, aspirated or embryo transfer cycles) must be specified.
Pregnancy diagnosed by ultrasonographic or clinical documentation of at least one fetus with heart beat. It includes ectopic pregnancy.
Precise and detailed plan for the study of a medical or biomedical problem and/or plan for a regimen of therapy.
An interdisciplinary process designed to improve the delivery of preventive, diagnostic, therapeutic, and rehabilitative measures in order to maintain, restore, and improve health outcomes of individuals and populations cost-effectively.
Clinical research is a branch of medical science that determines the safety and effectiveness of medications, devices, diagnostic products and treatment regimens intended for human use. These may be used for prevention, treatment, diagnosis or for relieving symptoms of a disease.
A health professional who works directly with patients, or uses data from patients, to do research on health and disease and to develop new treatments. Clinical researchers may also do research on how health care practices affect health and disease.
A case series in which the patients receive treatment in a clinic or other medical facility.
Clinical surveillance (or syndromic surveillance) refers to the surveillance (systematic collection, analysis, and interpretation) of health data about a clinical syndrome that has a significant impact on public health, which is then used to drive decisions about health policy and health education.
An experiment to compare the effects of two or more healthcare interventions. Clinical trial is an umbrella term for a variety of designs of healthcare trials, including uncontrolled trials, controlled trials, and randomized controlled trials. (Also called intervention study.)
Pre-planned studies of the safety, efficacy, or optimum dosage schedule (if appropriate) of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects.
Clinical trial [MeSH - publication type]: work that is the report of a pre-planned clinical study of the safety, efficacy, or optimum dosage schedule of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques in humans selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. While most clinical trials concern humans, this publication type may be used for clinical veterinary articles meeting the requisites for humans.
A clinical trial management system, also known as CTMS, is a customizeable software system used by the biotechnology and pharmaceutical industries to manage the large amounts of data involved with the operation of a clinical trial.
A clinical trial protocol is a document that describes the objective(s), design, methodology, statistical considerations, and organization of a clinical trial. The protocol usually also gives the background and reason the trial is being conducted, but these could be provided in other documents referenced in the protocol (such as an investigator's brochure).
A written description of a trial/study of any therapeutic, prophylactic, or diagnostic agent conducted in human subjects, in which the clinical and statistical description, presentations, and analyses are fully integrated into a single report.
The report of a pre-planned clinical study of the safety, efficacy, or optimum dosage schedule of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques in humans selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. While most clinical trials concern humans, this publication type may be used for clinical veterinary articles meeting the requisites for humans.
A result (e.g. a treatment effect) that is large enough to be of practical importance to patients and healthcare providers. This is not the same thing as statistically significant. Assessing clinical significance takes into account factors such as the size of a treatment effect, the severity of the condition being treated, the side effects of the treatment, and the cost. For instance, if the estimated effect of a treatment for acne was small but statistically significant, but the treatment was very expensive, and caused many of the treated patients to feel nauseous, this would not be a clinically significant result. Showing that a drug lowered the heart rate by an average of 1 beat per minute would also not be clinically significant.
A health professional who takes care of patients.
A population with no migratory flow either in or out, so that changes in population size occur only through births and deaths.
A form of innumeracy, in which a person knows about the risks but not how to draw conclusions or inferences from them. For instance, physicians often know the error rates of mammography and the base rate of breast cancer, but not how to infer from this information the chances that a woman with a positive test actually has breast cancer. Mind tools for overcoming clouded thinking, such as natural frequencies, are representations that facilitate drawing conclusions.
An aggregation of cases of a disease or other health-related condition, particularly cancer and birth defects, which are closely grouped in time and place. The number of cases may or may not exceed the expected number; frequently the expected number is not known.
Refers to a grouping of health-related events that are related temporally and in proximity.
A statistical procedure in which the unit of analysis matches the unit of randomization, which is something other than the patient or participant (e.g., school, clinic).
A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.
The assignment of groups (e.g., schools, clinics) rather than individuals to intervention and control groups. This approach is often used when assignment by individuals is likely to result in contamination (e.g., if adolescents within a school are assigned to receive or not receive a new sex education program, it is likely that they will share the information they learn with one another; instead, if the unit of assignment is schools, entire schools are assigned to receive or not receive the new sex education program). Cluster assignment is typically randomized, but it is possible (though not advisable) to assign clusters to treatment or control by other methods.
A trial in which clusters of individuals (e.g. clinics, families, geographical areas), rather than individuals themselves, are randomized to different arms. In such studies, care should be taken to avoid unit of analysis errors.
A type of random sampling, based first on the random selection of certain subgroups, from which the sample can be taken.
A cluster sample is one in which the whole population being studied is divided into clusters or groups, and a selection of these clusters is then made, and the entire population or a random sample of subjects within these sub-clusters are sampled. (e.g. if the sampling frame was an entire city, then the city would be broken down into city blocks and certain randomly selected city blocks would be sampled instead of the entire city).
A sampling design commonly used in retrospective mortality surveys when comprehensive lists of individual households cannot be obtained. Clusters are groups of households of which the first is chosen at random, and the remainder by a rule of proximity (e.g. second closest). In a cluster mortality survey, 30 or more clusters are usually sampled from the target study population, and each cluster usually contains at least 30 households.
Systematic statements of principles or rules of appropriate professional conduct, usually established by professional societies.
A method of analysis of qualitative data obtained for example in interviews, where categories are labeled to facilitate computer analysis and examination of relationships.
Manipulation, excessive pressure or influence to force or entice a person to enroll in a research project or a public health program (for example, screening, immunization). May take the form of excessive incentives, social pressure, use of authority figures, or playing upon perceived vulnerability of the person.
The use of force or intimidation to obtain compliance.
A group of individuals who share a common trait, such as birth year. In medicine, a cohort is a group that is part of a clinical trial or study and is observed over a period of time.
In epidemiology, a group of individuals with some characteristics in common.
A well-defined group of people who have had a common experience or exposure, who are then followed up for the incidence of new diseases or events, as in a cohort or prospective study. A group of people born during a particular period or year is called a birth cohort.
Observation of a cohort's demographic behavior through life or through many periods; for example, examining the fertility behavior of the cohort of people born between 1940 and 1945 through their entire childbearing years. Rates derived from such cohort analyses are cohort measures.
Variation in health status arising from different causal factors to which each birth cohort in a population is exposed as environment and society change.
A research study that compares a particular outcome in groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke compared with those who do not smoke).
The term used in clinical and epidemiological research to describe a longitudinal prospective observational study.
A type of observational analytic study. Enrollment into the study is based on exposure characteristics or membership in a group. Disease, death, or other health-related outcomes are then ascertained and compared.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
The application of additional diagnostic or therapeutic procedures to people receiving a particular programmed of treatment. In a controlled trial, members of either or both the experimental and the control groups might receive co-interventions.
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which the male reproductive organ enters the female reproductive tract.
The sexual union of a male and a female, a term used for human only.
Investigators who conduct similar randomized controlled trials and agree to contribute individual patient data from their trials to a meta-analysis.
Collected works [MeSH - publication type]: works consisting of collections of previously published works.
Comment [MeSH - publication type]: work consisting of a critical or explanatory note written to discuss, support, or dispute an article or other presentation previously published. It may take the form of an article, letter, editorial, etc. It appears in publications under a variety of names: comment, commentary, editorial comment, viewpoint, etc.
The process by which the health needs of the population are defined, priorities determined and appropriate services purchased and evaluated.
An approach to ethics emphasizing communal values, the common good, social goals, and traditional practices. Closely aligned with the cooperative virtues and a community's shared understanding of the good life. Often pitted against liberal individualism (that is, rights-based approaches) in its militant forms, a moderate communitarian view makes room for individual rights.
A unit, generally geographically defined, which is the locus of basic political and social responsibility and in which everyday social interactions involving all or most of the spectrum of life activities of the people within it takes place.
A clinical trial conducted primarily through primary-care physicians rather than academic research facilities.
Research conducted with the collaboration of a community for the purpose of taking action or effecting change. The community, in this case, could be any geographically, socioculturally, or occupationally defined group with common interests and goals. In both participatory research and community-based participatory research, the research questions generally emerge as a result of the attempt to move forward toward a set of objectives, not as the a priori reason for the research.
Collaborative process of research involving researchers and community representatives.
Research that is conducted in community settings and is intended to improve community-based interventions and community health.
The ability of a particular medical action to alter the national history of a particular disease for the better, under actual conditions of practice and use.
Persons trained to assist professional health personnel in communicating with residents in the community concerning needs and availability of health services.
General and comprehensive nursing practice directed to individuals, families, or groups as it relates to and contributes to the health of a population. This is not an official program of a Public Health Department.
Planning that has the goals of improving health, improving accessibility to health services, and promoting efficiency in the provision of services and resources on a comprehensive basis for a whole community.
Diagnostic, therapeutic and preventive health services provided for individuals in the community.
Community health workers (CHW), sometimes called "village health workers" are members of a community who are chosen by community members to provide basic health and medical care to their community. Other names for community health workers are village health workers (VHW), health workers and lay health advisors.
WHO Statistical Information System: includes traditional medicine practitioners, faith healers, assistant/community health-education workers, community health officers, family health workers, lady health visitors, health extension package workers, community midwives, institution-based personal care workers and traditional birth attendants.
A branch of medicine concerned with the total health of the individual within the home environment and in the community, and with the application of comprehensive care to the prevention and treatment of illness in the entire community.
Activities carried out at community level stimulating the involvement of community actors/institutions (for example: school, youth centre, neighborhood, city, city districts) in order to intervene in people's immediate surroundings and to facilitate active participation in a social context.
The presence of one or more diseases or conditions other than those of primary interest. In a study looking at treatment for one disease or condition, some of the individuals may have other diseases or conditions that could affect their outcomes. (A co-morbidity may be a confounder.)
The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.
Direct comparison of existing health care interventions to determine which work best for which patients and which pose the greatest benefits and harms.
Conduct and synthesis of systematic research comparing interventions and strategies to prevent, diagnose, treat, and monitor health conditions. The purpose of this research is to inform patients, providers, and decision-makers, responding to their expressed needs, about which interventions are most effective for which patients under specific circumstances.
Comparative study [MeSH - publication type]: comparison of outcomes, results, responses, etc for different techniques, therapeutic approaches or other inputs.
An investigational or marketed product (i.e., active control), or placebo, used as a reference in a clinical trial.
The groups being compared in the randomized trial. Also referred to as "study groups", "treatment groups", "the arms" of a trial, or by individual terms such as treatment and control groups.
A method of providing experimental therapeutics prior to final FDA approval for use in humans. This procedure is used with very sick individuals who have no other treatment options. Often, case-by-case approval must be obtained from the FDA for "compassionate use" of a drug or therapy.
A way to provide an investigational therapy to a patient who is not eligible to receive that therapy in a clinical trial, but who has a serious or life-threatening illness for which other treatments are not available. Compassionate use trials allow patients to receive promising but not yet fully studied or approved therapies when no other treatment option exists. Also called expanded access trial.
The investigators are aware of the outcome in every patient who participated in a study.
The number of children born per woman to a cohort of women by the end of their childbearing years.
Completeness considers whether the research evidence provides all the information that is required. For example, when evaluating evidence on public health interventions, reviewers need descriptive information on the intervention strategies that were adopted; the implementation of the intervention and how well it was done; the setting and circumstances in which it was implemented; whom the intervention reached (or did not reach); and how the intervention was received. Reviewers should also seek information on the unanticipated intervention effects, effect modification, and the potential harms of intervention.
Proportion of surveillance reports (or forms) received irrespective of when the reports were submitted. Proportion of reports received based on expected reporting units (if the system includes zero reporting).
Analysis of data from only those participants who remained at the end of the study.
Compliance (or adherence, or concordance) is a medical term that means the degree to which a patient correctly follows medical advice.
Adherence to all the trial-related requirements, good clinical practice (GCP) requirements, and the applicable regulatory requirements.
Voluntary cooperation of the patient in following a prescribed regimen.
Also called patient compliance, patient adherence.
When investigators measure the effect of treatment on an aggregate of endpoints of various importance. Inferences from composite endpoints are strongest in the rare situations in which (1) the component endpoints are of similar patient-importance, (2) the endpoints that are more important occur with at least similar frequency to those that are less important, and (3) strong biologic rationale supports results that, across component endpoints, show similar relative risks with sufficiently narrow confidence intervals.
Use of an interactive computer system designed to assist the physician or other health professional in choosing between certain relationships or variables for the purpose of making a diagnostic or therapeutic decision.
A strategy for changing clinician behavior. Computer-based information systems used to integrate clinical and patient information and provide support for decision making in patient care. In clinical decision support systems (CDSSs) that are computer based, detailed individual patient data are entered into a computer program and are sorted and matched to programs or algorithms in a computerized database, resulting in the generation of patient-specific assessments or recommendations. CDSSs can have the following purposes: alerting, reminding, critiquing, interpreting, predicting, diagnosing, and suggesting.
Randomization is concealed if the person who is making the decision about enrolling a patient is unaware of whether the next patient enrolled will be entered in the intervention or control group (using techniques such as central randomization or sequentially numbered opaque, sealed envelopes). If randomization is not concealed, patients with better prognoses may tend to be preferentially enrolled in the active intervention arm, resulting in exaggeration of the apparent benefit of intervention (or even falsely concluding that the intervention is efficacious).
The probability that an event A occurs given event B, usually written p(A|B). An example of a conditional probability is the probability of a positive screening mammogram given breast cancer, which is around 0.9.
Percentage of young people aged 15-24 years reporting the use of a condom during the last sexual intercourse with a non-regular partner among those who had sex with a non-regular partner in the last 12 months.
Percentage of women and men aged 15–49 who have had more than one sexual partner in the past 12 months who report the use of a condom during their last sexual intercourse.
A measure of the uncertainty around the main finding of a statistical analysis. Estimates of unknown quantities, such as the odds ratio comparing an experimental intervention with a control, are usually presented as a point estimate and a 95% confidence interval. This means that if someone were to keep repeating a study in other samples from the same population, 95% of the confidence intervals from those studies would contain the true value of the unknown quantity. Alternatives to 95%, such as 90% and 99% confidence intervals, are sometimes used. Wider intervals indicate lower precision; narrow intervals, greater precision. (Also called CI.)
A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.
The upper and lower boundaries of a confidence interval.
Refers to information, often of a private or sensitive nature, which a person has chosen to reveal but which is protected from being revealed to others. Confidential information should not be shared with anyone without consent except when there is a clear ethical justification (for example, approval by a human subjects research review panel), or a legal requirement (for example, regulations to protect children). Research use of identifiable data without consent requires showing importance of the research, minimal risk to those whose information is used, promise of benefit to society, and an obligation to maintain the confidentiality of the information.
The privacy of information and its protection against unauthorized disclosure.
Refers to maintaining the confidentiality of trial participants including their personal identity and all personal medical information. The trial participants' consent to the use of records for data verification purposes should be obtained prior to the trial and assurance must be given that confidentiality will be maintained.
Prevention of disclosure, to other than authorized individuals, of a sponsor's proprietary information or of a subject's identity.
A statement by a contributor to a report or review of personal, financial, or other interests that could have influenced someone.
A situation in which the private interests of someone involved in the assessment or evaluation process (e.g. interviewer, rater, scorer, evaluator) have an impact (either positive or negative) on the quality of the evaluation activities, the accuracy of the data or the results of the evaluation.
Conflict of interest relates to the fact that sponsoring from industry has been associated with restricted or selective publication of data. Thus, such studies may introduce bias if industry-sponsored studies tend to more often report positive results (which they actually do) and withhold data from studies showing no or harmful effects. Thus, studies may introduce the bias of overestimating the effectiveness of the technology.
A situation in which an individual might benefit personally from official or professional actions. It includes a conflict between a person's private interests and official responsibilities in a position of trust. The term is not restricted to government officials. The concept refers both to actual conflict of interest and the appearance or perception of conflict.
A comparison between two treatment groups that will give a biased estimate of the effect of treatment due to the study design. For a comparison to be unconfounded, the two treatment groups must be treated identically apart from the randomized treatment. For instance, to estimate the effect of heparin in acute stroke, a trial of heparin alone versus placebo would provide an unconfounded comparison. However, a trial of heparin alone versus aspirin alone provides a confounded comparison of the effect of heparin.
In statistics, a confounding variable (also confounding factor, lurking variable, a confound, or confounder) is an extraneous variable in a statistical model that correlates (positively or negatively) with both the dependent variable and the independent variable.
A characteristic that may be distributed differently between the study and control groups and that can effect the outcome being assessed. Confounding may be due to chance or bias.
A factor that is associated with both an intervention (or exposure) and the outcome of interest. For example, if people in the experimental group of a controlled trial are younger than those in the control group, it will be difficult to decide whether a lower risk of death in one group is due to the intervention or the difference in ages. Age is then said to be a confounder, or a confounding variable. Randomization is used to minimize imbalances in confounding variables between experimental and control groups. Confounding is a major concern in non-randomized studies.
Factors that can cause or prevent the outcome of interest, are not intermediate variables, and are not associated with the factor(s) under investigation. They give rise to situations in which the effects of two processes are not separated, or the contribution of causal factors cannot be separated, or the measure of the effect of exposure or risk is distorted because of its association with other factors influencing the outcome of the study.
Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.
Congresses [MeSH - publication type]: published records of the papers delivered at or issued on the occasion of individual congresses, symposia, and meetings; abstracts of papers delivered at such congresses; reports of the officers and delegates of such congresses; combinations of the foregoing; or proceedings of the conference of a society if they are not limited to matters of internal organization.
A method of “estimating the relative importance of different aspects of (health) care, the trade-offs between these aspects, and the total satisfaction or utility that respondents derive from health care services”. The most common method entails asking respondents to choose between a series of paired descriptions of alternative service configurations, from which the importance of the different attributes of each service can be estimated. The technique is now referred to as discrete choice experimentation.
A clinical study that includes all eligible patients identified by the researchers during the study registration period. The patients are treated in the order in which they are identified. This type of study usually does not have a control group.
A sample in which all potentially eligible patients seen over a period of time are enrolled.
A sampling procedure in which subjects are selected by taking every individual that presents over a specified period of time.
General agreement or collective opinion; the judgment arrived at by most of those concerned.
The process by which a group reaches agreement about the best solution to a problem or the best choice among alternative options.
Presentations of summary statements representing the majority agreement of physicians, scientists, and other professionals convening for the purpose of reaching a consensus--often with findings and recommendations--on a subject of interest. The Conference, consisting of participants representing the scientific and lay viewpoints, is a significant means of evaluating current medical thought and reflects the latest advances in research for the respective field being addressed.
Consensus development conference [MeSH - publication type]: a work that consists of summary statements representing the majority and current agreement of physicians, scientists, and other professionals meeting to reach a consensus on a selected subject.
If two sections in clinical evidence address the same question then we attempt to avoid repetition of the evidence, but aim instead to provide a cross reference.
Consistency means the results are replicated in studies in different settings or using different methods and thus the measured association is consistent.
A construct is a theoretically derived notion of the domain(s) we wish to measure. An understanding of the construct will lead to expectations about how an instrument should behave if it is valid. Construct validity therefore involves comparisons between measures and examination of the logical relationships, which should exist between a measure and characteristics of patients and patient groups.
Information intended for potential users of medical and healthcare services. There is an emphasis on self-care and preventive approaches as well as information for community-wide dissemination and use.
Community or individual involvement in the decision-making process.
A measurement that obtains reports or ratings from consumers about services received from an organization; in this context, this often means from a hospital, physician or health care provider.
Customer satisfaction or dissatisfaction with a benefit or service received.
In epidemiology, contact tracing is the identification and diagnosis of persons who may have come into contact with an infected person.
Identification of those persons (or animals) who have had such an association with an infected person, animal, or contaminated environment as to have had the opportunity to acquire the infection. Contact tracing is a generally accepted method for the control of sexually transmitted diseases.
In a controlled trial: the inadvertent application of the intervention being evaluated to people in the control group; or inadvertent failure to apply the intervention to people assigned to the intervention group. Fear of contamination is one motivation for performing a cluster randomized trial.
The extent to which a variable (e.g. a rating scale) measures what it is supposed to measure.
The conditions and circumstances that are relevant to the application of an intervention, for example the setting (in hospital, at home, in the air); the time (working day, holiday, night-time); type of practice (primary, secondary, tertiary care; private practice, insurance practice, charity); whether routine or emergency.
The process of establishing program objectives, approaches and procedures to respond to situations or events that are likely to occur, including identifying those events and developing likely scenarios and appropriate plans to prepare and respond to them in an effective manner.
A table of frequencies or counts. In a two-way contingency table, sub-categories of one characteristic are indicated horizontally (in rows) and subcategories of another characteristic are indicated vertically (in columns). Tests of association between the characteristics can be readily applied. The simplest two-way contingency table is the 2x2 table, which is used in clinical trials to compare dichotomous outcomes, such as death, for an experimental intervention and control group.
A two-variable table with cross-tabulated data.
Is a method of valuing the benefits of health services based on estimates of the maximum amount that people would be willing to pay for the availability of a service or the minimum amount that they would accept as compensation for not having the service available.
Data with a potentially infinite number of possible values within a given range. Height, weight and blood pressure are examples of continuous variables.
A variable that can theoretically take any value and in practice can take a large number of values with small differences between them (e.g., height). Continuous variables are also sometimes called interval data.
Data which are measured on a continuous scale. They are numbers that can be added, subtracted, multiplied and divided.
Prevention of conception by blocking fertility temporarily, or permanently (sterilization, reproductive). Common means of reversible contraception include natural family planning methods; contraceptive agents; or contraceptive devices.
Chemical substances that prevent or reduce the probability of conception.
Also called contraceptives.
Contraceptive methods include clinic and supply (modern) methods and non-supply (traditional) methods. Clinic and supply methods include female and male sterilization, intrauterine devices (IUDs), hormonal methods (oral pills, injectables, and hormone-releasing implants, skin patches and vaginal rings), condoms and vaginal barrier methods (diaphragm, cervical cap and spermicidal foams, jellies, creams and sponges). Traditional methods include rhythm, withdrawal, abstinence and lactational amenorrhea.
The percentage of women aged 15-49 years, married or in-union, who are currently using, or whose sexual partner is using, at least one method of contraception, regardless of the method used.
Contraceptive prevalence rate is the proportion of women of reproductive age who are using (or whose partner is using) a contraceptive method at a given point in time.
Percentage of couples currently using a contraceptive method.
A written, dated, and signed agreement between two or more involved parties that sets out any arrangements on delegation and distribution of tasks and obligations and, if appropriate, on financial matters. The protocol may serve as the basis of a contract.
Agreements between two or more parties, especially those that are written and enforceable by law.
A person or an organization (commercial, academic, or other) contracted by the sponsor to perform one or more of a sponsor's trial-related duties and functions.
A specific circumstance when the use of certain treatments could be harmful.
In a controlled trial: a participant in the arm that acts as a comparator for one or more experimental interventions. Controls may receive placebo, no treatment, standard treatment, or an active intervention, such as a standard drug.
In a case-control study: a person in the group without the disease or outcome of interest. In statistics: to adjust for, or take into account, extraneous influences or observations.
An animal in a study that does not receive the treatment being tested. Comparing the health of control animals with the health of treated animals allows researchers to evaluate the effects of a treatment more accurately.
In epidemiology and biostatistics, the control event rate (CER) is a measure of how often a particular statistical event (such as response to a drug, adverse event or death) occurs within the scientific control group of an experiment.
The standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.
In a controlled trial: the arm that acts as a comparator for one or more experimental interventions. (Also called comparison group.)
In a case-control study: the group without the disease or outcome of interest. (Also called comparison group.)
Groups that serve as a standard for comparison in experimental studies. They are similar in relevant characteristics to the experimental group but do not receive the experimental intervention.
In communicable (infectious) diseases: programs aimed at reducing or eliminating the disease.
A non-randomized study design where a control population of similar characteristics and performance as the intervention group is identified. Data are collected before and after the intervention in both the control and intervention groups.
A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.
An experiment or clinical trial that includes a comparison (control) group.
Clinical trials involving one or more test treatments, at least one control treatment, specified outcome measures for evaluating the studied intervention, and a bias-free method for assigning patients to the test treatment. The treatment may be drugs, devices, or procedures studied for diagnostic, therapeutic, or prophylactic effectiveness. Control measures include placebos, active medicines, no-treatment, dosage forms and regimens, historical comparisons, etc. When randomization using mathematical techniques, such as the use of a random numbers table, is employed to assign patients to test or control treatments, the trials are characterized as randomized controlled trials as topic.
Controlled clinical trial [MeSH - publication type]: work consisting of a clinical trial involving one or more test treatments, at least one control treatment, specified outcome measures for evaluating the studied intervention, and a bias-free method for assigning patients to the test treatment. The treatment may be drugs, devices, or procedures studied for diagnostic, therapeutic, or prophylactic effectiveness. Control measures include placebos, active medicine, no-treatment, dosage forms and regimens, historical comparisons, etc. When randomization using mathematical techniques, such as the use of a random numbers table, is employed to assign patients to test or control treatments, the trial is characterized as a randomized controlled trial.
A clinical trial that has a control. Such trials are not necessarily randomized.
Control is a standard against which experimental observations may be evaluated. In clinical trials, one group of participants is given an experimental drug, while another group (i.e., the control group) is given either a standard treatment for the disease or a placebo.
A group of individuals being studied because they are conveniently accessible in some way. This could make them particularly unrepresentative, as they are not a random sample of the whole population. A convenience sample, for example, might be all the people at a certain hospital, or attending a particular support group. They could differ in important ways from the people who haven't been brought together in that way: they could be more or less sick, for example.
Survey that is not based on a randomly selected, representative sample, but rather on data from households/individuals that can easily be reached or observed (e.g. people standing in a food-distribution queue).
Whatever the standard or usual treatment is for a particular condition at that time.
A committee that a sponsor may organize to coordinate the conduct of a multicenter trial.
An investigator assigned the responsibility for the coordination of investigators at different centers participating in a multicenter trial.
A set of exclusive rights granted to the author or creator of an original work, including the right to copy, distribute and adapt the work.
The exclusive right, granted by law for a certain number of years, to make and dispose of copies of a literary, musical or artistic work. In the United States the copyright is granted for the life of the author plus 50 years. In the case of a joint work, it is for the life of the last joint author to die, plus 50 years. In either case the copyright runs until the end of the calendar year 50 years after the author's death.
Corrected and republished article [MeSH - publication type]: work that is the republication of an article to correct, amplify, or restore text and data of the originally published article.
The strength and direction of the association between two variables. Correlation does not mean causation.
A statistic designed to measure the size and direction of the association between two variables. The value varies between 0 and ± 1 (1 means complete correlation).
A process of attributing cost to particular cost centers.
The assignment, to each of several particular cost-centers, of an equitable proportion of the costs of activities that serve all of them. Cost-center usually refers to institutional departments or services.
A type of economic study design in which both costs and benefits of interventions are expressed in monetary units, allowing direct comparison of competing interventions.
A form of economic evaluation through which questions primarily of allocative efficiency are addressed. Costs and outcomes are valued in a commensurate unit, often money, through techniques such as contingent valuation. This allows one to assess whether an intervention is worthwhile. Cost-benefit analysis provides a broader comparison between alternative claims on limited (societal) resources, enabling such comparisons to be made between treatment options within health care and even with options in other public sectors. Even if not everything can be valued in monetary terms, a cost-benefit framework is still useful as all impacts on costs and benefits can be laid out in a “balance sheet” to highlight where trade offs can be, or are being, made between tangible items (usually costs) and some intangibles.
A method of comparing the cost of a program with its expected benefits in dollars (or other currency). The benefit-to-cost ratio is a measure of total return expected per unit of money spent. This analysis generally excludes consideration of factors that are not measured ultimately in economic terms. Cost effectiveness compares alternative ways to achieve a specific set of results.
The containment, regulation, or restraint of costs. Costs are said to be contained when the value of resources committed to an activity is not considered excessive. This determination is frequently subjective and dependent upon the specific geographic area of the activity being measured.
The cost-effectiveness acceptability is plotted on a graph that relates the maximum one is willing to pay for a particular treatment alternative (e.g., how many dollars one is willing to pay to gain 1 life-year) on the x-axis to the probability that a treatment alternative is cost-effective compared with all other treatment alternatives on the y-axis. The curves are generated from uncertainty around the point estimates of costs and effects in trial-based economic evaluations or uncertainty around values for variables used in decision analytic models. As one is willing to pay more for health outcomes, treatment alternatives that initially might be considered unattractive (e.g., a high cost per life-year saved) will have a higher probability of becoming more cost-effective. Cost-effectiveness acceptability curves are a convenient method of presenting the effect of uncertainty on economic evaluation results on a single figure instead of through the use of numerous tables and figures of sensitivity analyses.
A type of economic study design in which the net monetary costs of a health care intervention per unit measure of clinical outcome or effectiveness allows direct comparison of competing interventions.
This form of analysis seeks to determine the costs and effectiveness of surveillance and response strategies and activities. It can be used to compare similar or alternative strategies and activities to determine the relative degree to which they will obtain the desired objectives or outcomes. The preferred strategy or action is one that has the least cost to produce a given level of effectiveness, or provides the greatest effectiveness for a given level of cost.
A form of economic evaluation applicable strictly only when outcomes are one dimensional and measured in naturally occurring units, such as changes in blood pressure or mortality. Within a given budget, a lower cost effectiveness ratio is better as more health can be produced by implementing that alternative. Where one program is both more expensive and more effective than its comparator, an incremental ratio can be calculated that depicts the extra cost per unit of outcome obtained, in comparing one treatment option to another. In this case, a value judgment will be required to assess whether the extra unit of outcome is worthwhile.
The cost and effectiveness results of each treatment alternative from an economic evaluation can be graphed on a figure known as the cost-effectiveness plane. The cost-effectiveness plane plots cost on the vertical axis (i.e., positive infinity at the top and negative infinity and the bottom) and effects such as life-years on the horizontal axis (i.e., negative infinity at the far left and positive infinity at the far right). One treatment alternative such as usual care is plotted at the origin (i.e., 0, 0), and all other treatment alternatives are plotted relative to the treatment at the origin. Treatment alternatives are considered dominated if they have both higher costs and lower effectiveness relative to any other. Line segments can be drawn connecting the nondominated treatment alternatives and the combination of line segments that join these nondominated treatment alternatives is referred to as the cost-effectiveness efficiency frontier. Constructed in this way, any treatment alternative that lies above the cost-effectiveness efficiency frontier is considered to be inefficient (dominated) by a treatment alternative or combination of alternatives on the efficiency frontier.
Cost-minimization is the simplest of the pharmacoeconomics tools and is applied when comparing two drugs of equal efficacy and equal tolerability.
An economic analysis conducted in situations in which the consequences of the alternatives are identical, and the only issue is their relative costs.
A specific type of cost effectiveness analysis in which the outcomes of the two (or more) comparators are assumed equal, thereby resulting in an assessment based solely on comparative cost. Making the assumption of equal outcomes can be risky, as such assumptions rarely hold in practice.
Total costs incurred by a society due to a specific disease.
The personal cost of acute or chronic disease. The cost to the patient may be an economic, social, or psychological cost or personal loss to self, family, or immediate community. The cost of illness may be reflected in absenteeism, productivity, response to treatment, peace of mind, quality of life, etc. It differs from health care costs, meaning the societal cost of providing services related to the delivery of health care, rather than personal impact on individuals.
An economic analysis that expresses effects as overall health improvement and describes how much it costs for some additional utility gain (e.g. cost per additional quality-adjusted life-year).
A form of economic evaluation that, compared with cost effectiveness or cost minimization analysis, enables broader comparisons to be made between treatments for different disease groups. Multi-dimensional health outcomes are reduced to a single index using health utilities and expressed as quality adjusted life years (QALYs), disability adjusted life years (DALYs) or healthy years equivalents (HYEs). Cost per unit of outcome ratios can then be derived that depict the costs required to obtain one QALY.
Share of population eligible for health care benefits (in-kind) under public programs.
Percentage of estimated total deaths that are 'counted' through vital registration system.
The process of establishing the qualifications of licensed professionals, organizational members or organizations, and assessing their background and legitimacy.
The recognition of professional or technical competence through registration, certification, licensure, admission to association membership, the award of a diploma or degree, etc.
In qualitative research, a term used instead of validity to reflect whether the investigators engaged thoroughly and sensitively with the material and whether the investigators’ interpretations are credible. Signs of credibility can be found not only in the procedural descriptions of methodology but also through an assessment of the coherence and depth of the findings reported.
Criteria of causation refer to a set of criteria used to assess the strength of a relation between a cause and an effect.
The process of assessing and interpreting evidence by systematically considering its validity, results, and relevance.
Critical appraisal criteria are checklists or standards that are used to evaluate research evidence. Critical appraisal criteria can be applied to assess the value of a single study, or they are used to appraise several studies as part of the process of systematic review. Critical appraisal criteria address different variables, depending on the nature and purpose of the research, and the expectations and priorities of the reviewers.
A strategy for changing clinician behavior. A decision support approach in which the computer evaluates a clinician’s decision and generates an appropriateness rating or an alternative suggestion.
This term is used to describe risks to human health that cross national borders. Examples include risks from climate change and the illegal drugs trade, as well as cross-border movements of people, which can lead to the spread of communicable diseases such as HIV/AIDS, malaria, TB and influenza.
Comparison of various psychological, sociological, or cultural factors in order to assess the similarities or diversities occurring in two or more different cultures or societies.
A trial in which participants receive one treatment and have outcomes measured, and then receive an alternative treatment and have outcomes measured again. The order of treatments is randomly assigned. Sometimes a period of no treatment is used before the trial starts and in between the treatments (washout periods) to minimize interference between the treatments (carry over effects). Interpretation of the results from crossover randomized controlled trials (RCTs) can be complex.
A type of clinical trial comparing two or more interventions in which the participants, upon completion of the course of one treatment, are switched to another. For example, for a comparison of treatments A and B, the participants are randomly allocated to receive them in either the order A, B or the order B, A. Particularly appropriate for study of treatment options for relatively stable health problems. The time during which the firs interventions is taken is known as the first period, with the second intervention being taken during the second period.
Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given.
An observational study design in which measurements are made on a single occasion.
A study design that involves surveying a population about an exposure, or condition, or both, at one point in time. It can be used for assessing prevalence of a condition in the population.
Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with longitudinal studies which are followed over a period of time.
Frequency distribution tables that examine the relationship between several of the variables at once, for better description of the data or in order to look for differences or relevant associations.
The ratio between the number of live births in a population during a given year and the total mid-year population for the same year, usually multiplied by 1,000.
The number of births over a given period divided by the person-years lived by the population over that period. It is expressed as number of births per 1,000 population. CBR = (births in a period / population of person-years over that period).
The number of divorces per 1,000 population in a given year.
The number of marriages per 1,000 population in a given year.
Mortality rate among all age groups and due to all causes. Often abbreviated to CMR.
The ratio between the number of deaths in a population during a given year and the total mid-year population for the same year, usually multiplied by 1,000.
The number of deaths per 1,000 population in a given year.
Also called crude death rate.
A crude prevalence rate is defined as the number of specified risk factor occurrences (i.e. daily smokers) over a specified period of time (e.g. a year) divided by the total population sampled. Crude prevalence rates are usually expressed as per cent of population sampled and may be calculated for males, females, persons or some other subset of the population. Example: Crude rate of current daily smokers (%) in population X = number of current daily smokers / total population sampled x 100
Term used when results have not been adjusted for confounding factors.
Rate of any demographic event computed for an entire population.
In a frequency distribution, the number or proportion of cases or events with a particular value or in a particular class interval, plus the total number or proportion of cases or events with smaller values of the variable.
A plot of the cumulative frequency rather than the actual frequency for each class interval of a variable. This type of graph is useful for identifying medians, quartiles, and other percentiles.
The probability that a particular event, such as occurrence of a particular disease, has occurred before a given time. It is equivalent to the incidence, calculated using a period of time during which all of the individuals in the population are considered to be at risk for the outcome. It is sometimes also referred to as the incidence proportion.
Incidence proportion (cumulative incidence) is the proportion of people who develop a condition within a fixed time period. An incidence proportion is synonymous with risk. For example, the proportion of people who develop a condition during their lifespan represents the lifetime risk of disease.
A meta-analysis in which studies are added one at a time in a specified order (e.g. according to date of publication or quality) and the results are summarized as each new study is added. In a graph of a cumulative meta-analysis, each horizontal line represents the summary of the results as each study is added, rather than the results of a single study.
A type of meta-analysis in which studies are sequentially pooled by adding each time one new study according to an ordered variable. For instance, if the ordered variable is the year of publication, studies will be ordered by it; then, a pooling analysis will be done every time a new article appears. It shows the evolution of the pooled estimate according to the ordered variable. Other common variables used in cumulative meta-analysis are the study quality, the risk of the outcome in the control group, the size of the difference between the groups, and other covariates (for example, mean time to treatment).
In formal education, a curriculum is the set of courses, and their content, offered at a school or university. Table of contents:
An impartial group that oversees a clinical trial and reviews the results to see if they are acceptable. This group determines if the trial should be changed or closed. Also called DSMB.
An independent committee, composed of community representatives and clinical research experts, that reviews data while a clinical trial is in progress to ensure that participants are not exposed to undue risk. A DSMB may recommend that a trial be stopped if there are safety concerns or if the trial objectives have been achieved.
An independent data monitoring committee that may be established by the sponsor to assess at intervals the progress of a clinical trial, the safety data, and the critical efficacy endpoints, and to recommend to the sponsor whether to continue, modify, or stop a trial.
A data clarification form (DCF) or data query form (DQF) is a questionnaire specifically used in clinical research. The DCF is the primary data clarification tool from the trial sponsor or contract research organization (CRO) towards the investigator to clarify discrepancies and ask the investigator for clarification. The DCF is part of the data validation process in a clinical trial.
Data cleansing or data scrubbing is the act of detecting and correcting (or removing) corrupt or inaccurate records from a record set, table, or database. Used mainly in databases, the term refers to identifying incomplete, incorrect, inaccurate, irrelevant etc. parts of the data and then replacing, modifying or deleting this dirty data.
A term used to describe a process of preparing and collecting data - for example as part of a process improvement or similar project.
Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.
Performing many analyses on the data from a study, for example looking for associations among many variables. Particularly used to refer to unplanned analyses, where there is no apparent hypothesis, and only statistically significant results are reported.
Data management is the development, execution and supervision of plans, policies, programs and practices that control, protect, deliver and enhance the value of data and information assets.
An expert committee set up to monitor the results of a continuing trial periodically, and assess whether or not the trial should continue or stop on ethical grounds, that is, if a treatment appears to be dramatically effective or harmful, and providing it or denying it to half the participants has become unethical.
Crude summation of the raw data with no weighting, to be distinguished from Crude summation of the raw data with no weighting, to be distinguished from meta-analysis).
A data set (or dataset) is a collection of data, usually presented in tabular form. Each column represents a particular variable. Each row corresponds to a given member of the data set in question.
In computer science, data validation is the process of ensuring that a program operates on clean, correct and useful data. It uses routines, often called "validation rules" or "check routines", that check for correctness, meaningfulness, and security of data that are input to the system.
An organized collection of data for one or more multiple uses.
Organized collections of computer records, standardized in format and content, that are stored in any of a variety of computer-readable modes. They are the basic sets of data from which computer-readable files are created.
Database [MeSH - publication type]: work consisting of a structured file of information or a set of logically related data stored and retrieved using computer-based means.
A set of computer programs that controls the creation, maintenance, and the use of a database.
Software designed to store, manipulate, manage, and control data for specific uses.
Medical and paramedical services delivered to patients that are formally admitted for diagnosis, treatment or other types of health care with the intention of discharging the patient the same day.
Institutional health care of patients during the day. The patients return home at night.
The number of deaths attributed to a particular disease during a specified time period divided by the number of new cases of that disease identified during the same time period.
We always precede decimal points with an integer. Numbers needing treatment to obtain one additional beneficial outcome (NNTs) are rounded up to whole numbers e.g. an NNT of 2.6 would become 3. Numbers needing treatment to obtain one additional harmful outcome (NNHs) are rounded down to whole numbers e.g., an NNH of 2.3 would become 2. For P values, we use a maximum of three noughts after the decimal: P < 0.0001. We try to report the number of decimal places up to the number of noughts in the trial population e.g., 247 people, with RR 4.837 would be rounded up to 4.84. We avoid use of more than three significant figures.
A tool that endeavors to present patients with the benefits and harms of alternative courses of action in a manner that is quantitative, comprehensive, and understandable.
A technique that formally identifies the options in a decision-making process, quantifies the probable outcomes (and costs) of each (and the uncertainty around them), determines the option that best meets the objectives of the decision-maker and assesses the robustness of this conclusion.
The mental processes (cognitive process) resulting in the selection of a course of action among several alternatives.
The process of making a selective intellectual judgment when presented with several complex alternatives consisting of several variables, and usually defining a course of action or an idea.
Mathematical or statistical procedures used as aids in making a decision. They are frequently used in medical decision-making.
Most clinical decision analyses are built as decision trees, and the articles usually will include one or more diagrams showing the structure of the decision tree used for the analysis.
A graphic device used in decision analysis, series of decision options are represented as branches (hierarchical).
Defensive medicine is the practice of diagnostic or therapeutic measures conducted primarily not to ensure the health of the patient, but as a safeguard against possible malpractice liability.
The alterations of modes of medical practice, induced by the threat of liability, for the principal purposes of forestalling lawsuits by patients as well as providing good legal defense in the event that such lawsuits are instituted.
One of the three major interpretations of probability (besides relative frequencies and propensities). The probability of an event is the subjective degree of belief a person has in that event. Historically, degrees of warranted belief entered probability theory from applications in the courtroom, such as the credibility of witnesses. Degrees of belief are constrained by the laws of probability (for example, probabilities need to add up to 1), that is, beliefs need to follow these laws to qualify as subjective probabilities.
A concept that refers to the number of independent contributions to a sampling distribution (such as chi-squared distribution). In a contingency table, it is one less than the number of row categories multiplied by one less than the number of column categories; e.g. a 2 x 2 table comparing two groups for a dichotomous outcome, such as death, has one degree of freedom.
The concept concerned with all aspects of providing and distributing health services to a patient population.
The "person characteristics--age, sex, race, and occupation--of descriptive epidemiology used to characterize the populations at risk.
Refers to a change in birth and death rates. As countries develop, they move through various stages of demographic transition: from virtually stagnant rates (high birth and death rates) to rapid growth (high birth rates, low death rates) and then to a stable low growth rate when both births and deaths are low.
The historical shift of birth and death rates from high to low levels in a population. The decline of mortality usually precedes the decline in fertility, thus resulting in rapid population growth during the transition period.
The statistical study of human populations.
The scientific study of human populations, including their sizes, compositions, distributions, densities, growth, and other characteristics, as well as the causes and consequences of changes in these factors.
Statistical interpretation and description of a population with reference to distribution, composition, or structure.
The lower portion of a fraction used to calculate a rate or ratio. In a rate, the denominator is usually the population (or population experience, as in person-years, etc.) at risk.
Number of community health workers per 10,000 population.
Number of environment and public health workers per 10,000 population.
Number of nursing and midwifery personnel per 10,000 population.
Number of other health service providers (excepting physicians, nursing and midwifery personnel, dentistry personnel and community health workers) per 10,000 population.
Number of medical doctors (physicians), including generalist and specialist medical practitioners, per 10,000 population.
A deontological approach to distributive justice holds that the clinician’s only responsibility should be to best meet the needs of the individual under his or her care. An alternative to the consequentialist or utilitarian view.
A duty-based theoretical approach to ethics, associated with the philosopher Kant. Right actions stem from freely embraced obligations to universal moral imperatives, such as the obligation to respect persons as ends and not as means.
The average number of economically dependent population per 100 economically productive population, for a given country, territory, or geographic area, at a specific point in time. In demographic terms, economically dependent population is defined as the sum of the population under 15 years of age plus the population 65 years of age and over, for a given country, territory, or geographic area, at a specific point in time, usually mid-year; economically productive population is defined as the population between 15 and 64 years of age, for the same country, territory, or geographic area, at the same specific point in time.
It is the ratio of the dependents (65 years and above) to those in the “economically productive” age group (15-64 years) i.e. number of persons aged 65 years and above per 100 persons between 15 and 64 years. Dependency Ratio also includes persons under 15 years age group.
The ratio of the economically dependent part of the population to the productive part; arbitrarily defined as the ratio of the elderly (ages 65 and older) plus the young (under age 15) to the population in the working ages (ages 15-64).
The outcome or response that results from changes to an independent variable. In a clinical trial, the outcome (over which the investigator has no direct control) is the dependent variable, and the treatment arm is the independent variable. The dependent variable is traditionally plotted on the vertical axis on graphs. (Also called outcome variable.)
In a statistical analysis, the outcome variable(s) or the variable(s) whose values are a function of other variable(s) (called independent variable(s) in the relationship under study).
Depopulation (also known as population decline) is a term used to describe any great reduction in a human population.
The state of population decline.
The area of bibliography which makes known precisely the material conditions of books, i.e., the full name of the author, the exact title of the work, the date and place of publication, the publisher's and printer's names, the format, the pagination, typographical particulars, illustrations, and the price, and for old books, other characteristics such as the kind of paper, binding, etc. It is also called analytical bibliography and physical bibliography.
The aspect of epidemiology concerned with organizing and summarizing health-related data according to time, place, and person.
Statistics designed to summarize and describe characteristics of the data. Descriptive statistics helps us to make sense of a large volume of data.
A study that describes characteristics of a sample of individuals. Unlike an experimental study, the investigators do not actively intervene to test a hypothesis, but merely describe the health status or characteristics of a sample from a defined population.
A design is a plan which indicates how often, when and from whom information will be gathered during the course of an evaluation. Good design is essential if the results of an evaluation are to have any future use. A design with at least one experimental group and one control group is known as a control group design; a time-series design uses only one experimental group but at least three data collections; and a design which does not use a control group or time series analysis is the pre- and post- design.
A number that describes how much larger a sample is needed in designs such as cluster randomized trials to achieve the same precision as a simple random sample. It is the ratio of the true variance of a statistic (taking the sampling design into account) to the variance of the statistic for a simple random sample with the same number of cases.
A specific form of bias attributable to intraclass correlation in cluster sampling. The design effect for a cluster design is the ratio of the variance for that design to the variance calculated from a simple random sample of the same size.
Systematic difference between comparison groups in how outcomes are ascertained, diagnosed or verified. (Also called ascertainment bias.)
Any definable factor that effects a change in a health condition or other characteristic.
Any factor, whether event, characteristic, or other definable entity, that brings about change in a health condition, or in other defined characteristics.
A method of allocating participants to interventions that uses a pre-determined rule without a random element (e.g., alternate assignment, based on day of week, hospital number, or date of birth). Because group assignments can be predicted in advance of assignment in deterministic methods, participant allocation may be manipulated, causing selection bias.
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Process that is gone through in order for a device to receive approval by a government regulatory agency. This includes any required preclinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance. It is not restricted to FDA.
A way of categorizing patients according to diagnosis and intensity of resources required, usually for the period of one hospital stay.
A system for classifying patient care by relating common characteristics such as diagnosis, treatment, and age to an expected consumption of hospital resources and length of stay. Its purpose is to provide a framework for specifying case mix and to reduce hospital costs and reimbursements and it forms the cornerstone of the prospective payment system.
Incorrect diagnoses after clinical examination or technical diagnostic procedures.
The process of gaining approval by a government regulatory agency for diagnostic reagents and test kits. This includes any required preclinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance.
Refers to trials that are conducted to find better tests or procedures for diagnosing a particular disease or condition. Diagnostic trials usually include people who have signs or symptoms of the disease or condition being studied.
Data that can take one of two possible values, such as dead/alive, smoker/non-smoker, present/not present. (Also called binary data.) Sometimes continuous data or ordinal data are simplified into dichotomous data (e.g. age in years could become <75 years or ≥75 years).
A variable that can take one of two discrete values rather than values incrementally placed along a continuum (e.g., male or female, pregnant or not pregnant, dead or alive).
A dictionary, also referred to as a lexicon, wordbook, or vocabulary, is a collection of words in one or more specific languages, often listed alphabetically, with usage information, definitions, etymologies, phonetics, pronunciations, and other information; or a book of words in one language with their equivalents in another, also known as a lexicon.
Dictionary [MeSH - publication type]: a reference book containing a list of words - usually in alphabetical order - giving information about form, pronunciation, etymology, grammar, and meaning. A foreign-language dictionary is an alphabetical list of words of one language with their meaning and equivalents in another language.
The set of diagnoses that can plausibly explain a patient’s presentation.
Determination of which one of two or more diseases or conditions a patient is suffering from by systematically comparing and contrasting results of diagnostic measures.
When test results influence the choice of the reference standard (e.g., test-positive patients undergo an invasive test to establish the diagnosis, whereas test-negative patients undergo long-term follow-up without application of the invasive test), the assessment of test properties may be biased.
The study of the factors necessary for successful adoption and implementation by additional stakeholders and the targeted population of an evidence-based intervention that has been successfully implemented in some sites, resulting in widespread use.
Permission to examine, analyze, verify, and reproduce any records and reports that are important to evaluation of a clinical trial. Any party (e.g., domestic and foreign regulatory authorities, sponsors, monitors, and auditors) with direct access should take all reasonable precautions within the constraints of the applicable regulatory requirement(s) to maintain the confidentiality of subjects' identities and sponsor's proprietary information.
The research hypothesis outlining a relationship may be directional or non-directional. For example, a relationship between smoking and cardiovascular disease can only be directional. It is expected in the hypothesis that it will increase cardiovascular disease. The relationship between oral hormonal contraceptives and certain disease conditions can be non-directional. The disease conditions may increase or decrease as a result of oral hormonal contraceptive use.
Lists of persons or organizations, systematically arranged, usually in alphabetic or classed order, giving address, affiliations, etc., for individuals, and giving address, officers, functions, and similar data for organizations.
Directory [MeSH - publication type]: work consisting of an alphabetical or classified list of names, organizations, subjects, etc., giving usually titles, addresses, affiliations, and other professional data.
An international measure of the burden of disease that expresses both time lost through premature death and time lived with a disability.
A method for measuring disease burden, which aims to quantify in a single figure both the quantity and quality of life lost or gained by a disease, risk factor, or treatment. The DALYs lost or gained are a function of the expected number of years spent in a particular state of health, multiplied by a coefficient determined by the disability experienced in that state (ranging from 0 [optimal health] to 1 [deaths]). Later years are discounted at a rate of 3% per year, and childhood and old age are weighted to count for less.
A unit for measuring both the global burden of disease and the effectiveness of health interventions, as indicated by reductions in the disease burden. It is calculated as the present value of the future years of disability-free life that are lost as the result of the premature deaths or cases of disability occurring in a particular year.
Disbenefits are adverse effects on health or its determinants consequent on implementing a proposal.
The official termination of a patient’s stay in a hospital or other medical facility to which one has been admitted.
Disclosure means the giving out of information, either voluntarily or to be in compliance with legal regulations or workplace rules.
Revealing of information, by oral or written communication.
Refers to the process of adjusting the value of costs or benefits that occur at different points of time in the future so that they may all be compared as if they had occurred at the same time. Discounting is necessary if there is a preference to defer costs until tomorrow or to enjoy benefits today (positive time preference). The discount rate describes the “interest rate” with which the present value of future costs and benefits is estimated. There is little agreement over what discount rate to use, but to ensure comparability Gold et al recommend using 3% in the base case and 5% in a sensitivity analysis.
Numerical variables that are not measured on a continuous scale.
A statistical analytic technique used with discrete dependent variables, concerned with separating sets of observed values and allocating new values. It is sometimes used instead of regression analysis.
Period after successful treatment in which there is no appearance of the symptoms or effects of the disease.
Refers to the processes and people concerned with improving or maintaining health in large populations. It is concerned with common chronic illnesses, and the reduction of future complications associated with those diseases.
A broad approach to appropriate coordination of the entire disease treatment process that often involves shifting away from more expensive inpatient and acute care to areas such as preventive medicine, patient counseling and education, and outpatient care. This concept includes implications of appropriate versus inappropriate therapy on the overall cost and clinical outcome of a particular disease.
Notification or reporting by a physician or other health care provider of the occurrence of specified contagious diseases such as tuberculosis and HIV infections to designated public health agencies. The United States system of reporting notifiable diseases evolved from the Quarantine Act of 1878, which authorized the US Public Health Service to collect morbidity data on cholera, smallpox, and yellow fever; each state in the US has its own list of notifiable diseases and depends largely on reporting by the individual health care provider.
Disease registries are collections of secondary data related to patients with a specific diagnosis, condition, or procedure.
Disease-specific HRQL measures evaluate the full range of patients’ problems and experiences relevant to a specific condition or disease.
Disease surveillance is an epidemiological practice by which the spread of disease is monitored in order to establish patterns of progression.
Disentanglement strategies seek to establish structures and systems that protect independent research and reviews that are free from the influence of vested interests.
A specialized ambulatory facility which can be assigned to a hospital or serve as an independent institution.
The study of how the targeted distribution of information and intervention materials to a specific audience can be successfully executed so that increased spread of this knowledge achieves greater use and has increased impact.
The collection of values of a variable in the population or the sample, sometimes called an empirical distribution.
The complete summary of the frequencies of the values or categories of a measurement made on a group of persons. The distribution tells either how many or what proportion of the group was found to have each value (or range of values) out of all the possible values that the quantitative measure can have.
In epidemiology, the frequency and pattern of health-related characteristics and events in a population. In statistics, the observed or theoretical frequency of values of a variable.
Distribution of main causes of death among children aged < 5 years, expressed as percentage of total deaths. The causes of death refers to the concept of the 'underlying cause of death' as defined by ICD-10 (WHO, 1992).
Distribution of years of life lost by broader causes, expressed as percentage of total of years of life lost.
An ethical principle implying that participation in the research should correlate with expected benefits. No population group should carry an undue burden of research for the benefit of another group.
Divorce demography is the measurement of the frequency of marriage and divorce. It is most commonly measured in three different ways: the current marriage to current divorce ratio, the crude divorce rate, and the refined divorce rate. The current marriage to current divorce ratio measures the divorce rate by comparing the number of marriages to the number of divorces in a given year. The crude divorce rate is the number of divorces per 1,000 population. The refined divorce rate measures the number of divorces per 1,000 women married to men, and is the better of the three measurement methods.
All records, in any form (including, but not limited to, written, electronic, magnetic, and optical records; and scans, x-rays, and electrocardiograms) that describe or record the methods, conduct, and/or results of a trial, the factors affecting a trial, and the actions taken.
Systematic organization, storage, retrieval, and dissemination of specialized information, especially of a scientific or technical nature. It often involves authenticating or validating information.
The amount of medicine taken, or radiation given, at one time.
A response to a drug which may be related to the amount received (i.e. the dose). Sometimes trials are done to test the effect of different dosages of the same drug. This may be true for both benefits and harms.
Refers to the effects of treatment with a drug. If the effects change when the dose of the drug is changed, the effects are said to be dose-dependent.
Describes side effects of a drug or other treatment that are serious enough to prevent an increase in dose or level of that treatment.
A clinical trial in which two or more doses of an agent (such as a drug) are tested against each other to determine which dose works best and is least harmful.
The strength of a treatment given over a period of time.
The relationship between the quantity of treatment given and its effect on outcome. In meta-analysis, dose-response relationships can be investigated using meta-regression.
A visual display of the actual data points of a noncontinuous variable.
A clinical trial design in which neither the participating individuals nor the study staff knows which participants are receiving the experimental drug and which are receiving a placebo (or another therapy). Double-blind trials are thought to produce objective results, since the expectations of the doctor and the participant about the experimental drug do not affect the outcome; also called double-masked study.
A clinical trial in which neither the medical staff nor the person knows which of several possible therapies the person is receiving.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
A technique for retaining the blind when administering supplies in a clinical trial, when the two treatments cannot be made identical. Supplies are prepared for Treatment A (active and indistinguishable placebo) and for Treatment B (active and indistinguishable placebo). Subjects then take two sets of treatment; either A (active) and B (placebo), or A (placebo) and B (active).
The principle of double effect; also known as the rule of double effect; the doctrine of double effect, abbreviated to DDE; double-effect reasoning; or simply double effect, is a set of ethical criteria for evaluating the permissibility of acting when one's otherwise legitimate act (for example, relieving a terminally ill patient's pain) will also cause an effect one would normally be obliged to avoid (for example, the patient's death.)
Guideline for determining when it is morally permissible to perform an action to pursue a good end with knowledge that the action will also bring about bad results. It generally states that, in cases where a contemplated action has such double effect, the action is permissible only if: it is not wrong in itself; the bad result is not intended; the good result is not a direct causal result of the bad result; and the good result is "proportionate to" the bad result.
The doubling time is the period of time required for a quantity to double in size or value.
The number of years required for the population of an area to double its present size, given the current rate of population growth.
Costs due to resources consumed in the future and associated with clinical events in the future that are attributable to the intervention.
Refers to the ability to trace a statement from its most condensed form through to the original evidence that supports it. This requires not only the data but also all the methods used in the generation of the condensed form to be explicit and reproducible. We see it as an important component of the quality of evidence-based publications.
A subject in a clinical trial who for any reason fails to continue in the trial until the last visit required of him/her by the study protocol.
Also called patient dropout.
Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.
Process that is gone through in order for a drug to receive approval by a government regulatory agency. This includes any required pre-clinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance of the drug.
Similar effects produced by most or all members of a class of drugs (e.g., beta blockers, calcium antagonists, or angiotensin converting enzyme inhibitors).
Drug design, also sometimes referred to as rational drug design, is the inventive process of finding new medications based on the knowledge of the biological target.
The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis, or drug administration analysis.
Drug development is a blanket term used to define the entire process of bringing a new drug or device to the market. It includes drug discovery / product development, pre-clinical research (microorganisms/animals) and clinical trials (on humans).
In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which drugs are discovered and/or designed.
The process of finding chemicals for potential therapeutic use.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Any process by which toxicity, metabolism, absorption, elimination, preferred route of administration, safe dosage range, etc., for a drug or group of drugs is determined through clinical assessment in humans or veterinary animals.
A situation in which a substance affects the activity of a drug, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own.
The action of a drug that may affect the activity, metabolism, or toxicity of another drug.
The process of observing, recording, or detecting the effects of a chemical substance administered to an individual therapeutically or diagnostically.
Drug repositioning (also known as drug repurposing, drug re-profiling, therapeutic switching and drug re-tasking) is the application of known drugs and compounds to new indications (i.e., new diseases).
Manifestations of the adverse effects of drugs administered therapeutically or in the course of diagnostic techniques. It does not include accidental or intentional poisoning for which specific headings are available.
Publication of a paper that overlaps substantially with one already published by the same authors.
Simultaneous or successive publishing of identical or near- identical material in two or more different sources without acknowledgment. It differs from reprinted publication in that a reprint cites sources. it differs from plagiarism in that duplicate publication is the product of the same authorship while plagiarism publishes a work or parts of a work of another as one's own.
Duplicate publication [MeSH - publication type]: work consisting of an article or book of identical or nearly identical material published simultaneously or successively to material previously published elsewhere, without acknowledgment of the prior publication.
Trials can be reported more than once, a process known as duplication. Duplication can be justified, for instance where results from a study at two years are followed later by results at four years. Another example might be reporting different results from a single trials (clinical or economic, for instance). But multiple publication can also be covert, and lead to over-estimation of the amount of information available.
The ethical and/or legal obligation of a health provider or researcher to communicate with a former patient or research subject about advances in research relevant to a treatment or to a genetic or other diagnostic test provided earlier, or about proposed new uses of blood or tissue samples taken in the past for another purpose.
A health professional's obligation to breach patient confidentiality to warn third parties of the danger of their being assaulted or of contracting a serious infection. Table of contents:
E-epidemiology is the science underlying the acquisition, maintenance and application of epidemiological knowledge and information using digital media such as the internet, mobile phones, digital paper, digital TV. E-epidemiology also refers to the large-scale epidemiological studies that are increasingly conducted through distributed global collaborations enabled by the Internet.
E-health is the transfer of health resources and health care by electronic means.
Methods to determine in patients the nature of a disease or disorder at its early stage of progression. generally, early diagnosis improves prognosis and treatment outcome.
Earlier than planned termination of clinical trials.
In clinical evidence a systematic review should be excluded (eclipsed) if, and only if, there is a review with a later search date with either identical methods, clearly superior methods, or similar methods including the same primary sources.
An ecological study is an epidemiological study in which the unit of analysis is a population rather than an individual. For instance, an ecological study may look at the association between smoking and lung cancer deaths in different countries.
Comparison of the relationship between costs and outcomes of alternative healthcare interventions.
Economic epidemiology is a field at the intersection of epidemiology and economics. Its premise is to incorporate incentives for healthy behavior and their attendant behavioral responses into an epidemiological context to better understand how diseases are transmitted. This framework should help improve policy responses to epidemic diseases by giving policymakers and health-care providers clear tools for thinking about how certain actions can influence the spread of disease transmission.
A “comparative analysis of alternative courses of action in terms of both their costs and consequences”. Two essential features of this definition are worth noting. Firstly, economic evaluation involves a comparison between alternative courses of action. Secondly, the options are evaluated in terms of both their costs and their benefits. Such analyses can be set within the context of a randomized control trial or other health research study design, or can be undertaken through decision analysis modeling approaches.
A consequence of the use of health care products, services, or programs that affect costs from any of several perspectives.
A potentially life-threatening condition in which the embryo, mammalian implants outside the cavity of the uterus. Most ectopic pregnancies (>96%) occur in the fallopian tubes, known as tubal pregnancy. They can be in other locations, such as uterine cervix; ovary; and abdominal cavity (pregnancy, abdominal).
Editorial [MeSH - publication type]: work consisting of a statement of the opinions, beliefs, and policy of the editor or publisher of a journal, usually on current matters of medical or scientific significance to the medical community or society at large. The editorials published by editors of journals representing the official organ of a society or organization are generally substantive.
A group of people, usually at a publication, who dictate the tone and direction the publication's editorial policy will take.
The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.
In this process, articles which meet the minimum requirements for submission (such as including the necessary descriptions of funding, privacy and publication releases, ethics/institutional review board approval, statements of original work, signatures of authors, and so on,) are first looked over by a managing editor or a member of an editorial board. They may be referred back to the authors for revision and resubmission, rejected, or presented to the editorial board for final approval.
A strategy for changing clinician behavior. Participation of professionals in workshops that include interaction and discussion.
Factors that modify the effect of the putative causal factor(s) under study.
A generic term for the estimate of effect of treatment for a study.
A dimensionless measure of effect that is typically used for continuous data when different scales (e.g. for measuring pain) are used to measure an outcome and is usually defined as the difference in means between the intervention and control groups divided by the standard deviation of the control or both groups.
A standardized scale free estimate of the relation between an exposure and an outcome. In a general sense, this term is applied to any measurement of the difference in the outcome between the study groups (so relative risk, odds ratio, and risk difference can be defined as “effect sizes”). When the effect size is applied to measurements of continuous variables (such as mean), its most common estimator is the standardized mean difference, which is calculated as the difference of means divided by the variability of the measures (the standard deviation). This is mainly useful when there is no common measure to all the studies.
The extent to which a specific intervention, when used under ordinary circumstances, does what it is intended to do. Clinical trials that assess effectiveness are sometimes called pragmatic or management trials.
In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.
A measure of the extent to which a specific intervention, procedure, regimen, or service, when deployed in the field in routine circumstances, does what it is intended to do for a specific population; a measure of the extent to which a health care intervention/activity fulfills its objectives.
The benefit (e.g. to health outcomes) of using a technology for a particular problem under general or routine conditions, for example by a physician in a community hospital or by a patient at home.
Research to determine whether an intervention produces desired results under the conditions in which the intervention is likely to be used.
The extent to which an intervention produces a beneficial result under ideal conditions. Clinical trials that assess efficacy are sometimes called explanatory trials and are restricted to participants who fully co-operate.
The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed. In the procedure mandated by the FDA, Phase II clinical trials gauge efficacy, and Phase III trials confirm it.
The benefit of using a technology for a particular problem under ideal conditions, for example, in a laboratory setting, with in the protocol of a carefully managed randomized controlled trial, or at a “center of excellence.”
Research to determine whether an intervention produces desired results under optimal or near optimal conditions.
The extent to which objectives are achieved by minimizing the use of resources.
A procedure to detect publication bias. It consists in a simple linear regression of the effect size in a study divided by its standard error on the inverse of standard error and testing whether the intercept is statistically significant (at p < 0.1).
An electronic data capture (EDC) system is a computerized system designed for the collection of clinical data in electronic format for use mainly in human clinical trials.
An electronic health record (EHR) (also electronic patient record or computerized patient record) is an evolving concept defined as a systematic collection of electronic health information about individual patients or populations.
Media that facilitate transportability of pertinent information concerning patient's illness across varied providers and geographic locations. Some versions include direct linkages to online consumer health information that is relevant to the health conditions and treatments related to a specific patient.
In clinical trials, requirements that must be met for an individual to be included in a study. These requirements help make sure that patients in a trial are similar to each other in terms of specific factors such as age, general health, and previous treatment. When all participants meet the same eligibility criteria, it gives researchers greater confidence that results of the study are caused by the intervention being tested and not by other factors.
Summary criteria for participant selection; includes inclusion and exclusion criteria.
The product of the division of the zygote to the end of the embryonic stage, eight weeks after fertilization. (This definition does not include either parthenotes - generated through parthenogenesis - nor products of somatic cell nuclear transfer.)
Early pregnancy loss during the embryo, mammalian stage of development. In the human, this period comprises the second through eighth week after fertilization.
Experimentation on, or using the organs or tissues from, a human or other mammalian conceptus during the prenatal stage of development that is characterized by rapid morphological changes and the differentiation of basic structures. In humans, this includes the period from the time of fertilization to the end of the eighth week after fertilization.
Emergency management (or disaster management) is the discipline of dealing with and avoiding risks.
A branch of emergency services dedicated to providing out-of-hospital acute medical care and/or transport to definitive care, to patients with illnesses and injuries which the patient, or the medical practitioner, believes constitutes a medical emergency.
Services specifically designed, staffed, and equipped for the emergency care of patients.
Mortality rate above which an emergency is said to be occurring. Usually taken as a crude mortality rate of 1 per 10,000 per day, or as an under-five mortality rate of 2 per 10,000 per day.
Empirical results are based on observation rather than on reasoning alone.
Based on experimental data, not on a theory.
Research that derives its data by means of direct observation or experiment, such research is used to answer a question or test a hypothesis (e.g. "Does something such as a type of medical treatment work?").
The study, based on direct observation, use of statistical records, interviews, or experimental methods, of actual practices or the actual impact of practices or policies.
A type of reference work, a compendium holding information from either all branches of knowledge or a particular branch of knowledge.
Encyclopedias [MeSH - publication type]: works containing informational articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject.
In epidemiology, an infection is said to be endemic (from Greek en- in or within + demos people) in a population when that infection is maintained in the population without the need for external inputs. For example, chickenpox is endemic (steady state) in the UK, but malaria is not.
The constant presence of a disease or infectious agent within a given geographic area or population group; may also refer to the usual prevalence of a given disease within such area or group.
Describes a disease that is constantly present, to a greater or lesser degree, in a population living in a particular area.
The constant presence of diseases or infectious agents within a given geographic area or population group. It may also refer to the usual prevalence of a given disease with such area or group. It includes holoendemic and hyperendemic diseases. A holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). A hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally.
In clinical trials, an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor.
Overall outcome that the protocol is designed to evaluate. Common endpoints are severe toxicity, disease progression, or death.
Establishment of the level of a quantifiable effect indicative of a biologic process. The evaluation is frequently to detect the degree of toxic or therapeutic effect.
The act of admitting a participant into a trial. Participants should be enrolled only after study personnel have confirmed that all the eligibility criteria have been met. Formal enrollment must occur before randomized assignment.
WHO Statistical Information System: includes environmental and public health officers, sanitarians, hygienists, environmental and public health technicians, district health officers, malaria technicians, meat inspectors, public health supervisors and similar professions.
Environmental epidemiology is the branch of public health that deals with environmental conditions and hazards that may pose a risk to human health. Environmental epidemiology identifies and quantifies exposures to environmental contaminants; conducts risk assessments and risk communication; provides medical evaluation and surveillance for adverse health effects; and provides health-based guidance on levels of exposure to such contaminants.
The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.
In epidemiology, an environmental factor (or so called environmental trigger) are those determinants of disease that are not transmitted genetically. In more basic terms, an environmental factor is a factor caused, aided, or triggered by the environment.
An extrinsic factor (geology, climate, insects, sanitation, health services, etc.) which affects the agent and the opportunity for exposure.
The branch of public health that is concerned with all aspects of the natural and built environment that may affect human health.
The science of controlling or modifying those conditions, influences, or forces surrounding man which relate to promoting, establishing, and maintaining health.
A multidisciplinary field involving medicine, environmental science, chemistry and others. The scope of this field involves studying the interactions between environment and human health, and the role of the environment in causing or mediating disease.
Medical specialty concerned with environmental factors that may impinge upon human disease, and development of methods for the detection, prevention, and control of environmentally related disease.
Environmental monitoring describes the processes and activities that need to take place to characterize and monitor the quality of the environment.
The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment or workplace by measuring the amounts of these toxicants in the bodies of people and animals in that environment, among other methods. It also includes the measurement of environmental exposure. Levels in humans and animals are used as indicators of toxic levels of undesirable chemicals.
Environmental strategies are prevention strategies aimed at the immediate cultural, political and social environment of people.
Transitory written and printed matter not intended to be retained or preserved.
Ephemera [MeSH - publication type]: works consisting of transient everyday items, usually printed on paper, that are produced for a specific limited use and then often thrown away.
Literature judged to have a short period of usefulness and only for a small audience, not normally considered worth indexing or cataloguing. It may, however, be important. It includes reports, proceedings of conferences and other types of publication.
In epidemiology, an epidemic epi- meaning "upon or above" and demic- meaning "people", occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is "expected," based on recent experience (the number of new cases in the population during a specified period of time is called the "incidence rate").
The occurrence in a community or region of cases of an illness, specific health-related behavior, or other health-related events clearly in excess of normal expectancy. The community or region and the period in which the cases occur are specified precisely. The number of cases indicating the presence of an epidemic varies according to the agent, size, and type of population exposed, previous experience or lack of exposure to the disease, and time and place of occurrence.
The occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time.
A histogram that shows the course of a disease outbreak or epidemic by plotting the number of cases by time of onset.
A simplified means of describing the transmission of communicable disease through individuals.
A time period when the number of cases of disease reported is greater than expected.
Is the critical number or density of susceptible hosts required for an epidemic to occur. The epidemic threshold is used to confirm the emergence of an epidemic so as to step-up appropriate control measures.
Events, characteristics, or other definable entities that have the potential to bring about a change in a health condition or other defined outcome.
Statistical calculations on the occurrence of disease or other health-related conditions in defined populations.
The form and structure of analytic studies in epidemiologic and clinical research.
Studies designed to examine associations, commonly, hypothesized causal relations. They are usually concerned with identifying or measuring the effects of risk factors or exposures. The common types of analytic study are case-control studies; cohort studies; and cross-sectional studies.
Types and formulations of studies used in epidemiological and clinical research.
The traditional model of infectious disease causation. Includes three components: an external agent, a susceptible host, and an environment that brings the host and agent together, so that disease occurs.
In demography and medical geography, epidemiological transition is a human phase of development witnessed by a sudden and stark increase in population growth rates brought about by medical innovation in disease or sickness therapy and treatment, followed by a re-leveling of population growth from subsequent declines in procreation rates.
The study of the health of populations and communities, not just particular individuals.
The branch of medical science that deals with the study of incidence and distribution and control of a disease in a population.
The study of the patterns, causes, and control of disease in groups of people.
The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.
Field of medicine concerned with the determination of causes, incidence, and characteristic behavior of disease outbreaks affecting human populations. It includes the interrelationships of host, agent, and environment as related to the distribution and control of disease.
An interval of care by a health care facility or provider for a specific medical problem or condition. It may be continuous or it may consist of a series of intervals marked by one or more brief separations from care, and can also identify the sequence of care (e.g., emergency, inpatient, outpatient), thus serving as one measure of health care provided.
Clusters of visits and/or procedures that are related to a particular illness, disease, or condition.
Principle by which all persons or things under consideration are treated in the same way.
The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.
A state of uncertainty where a person believes it is equally likely that either of two treatment options is better.
A state of uncertainty on the part of an investigator or a community of investigators regarding the relative merits of interventions. From middle French terms meaning equal weight. Equipoise is an ethical problem when a professional believes one study intervention is superior. Randomly assigning groups of persons to the alternative intervention thus conflicts with an obligation to do the best for the patient or community. “Community” or “clinical” equipoise—collective professional uncertainty—may be invoked to make trial participation ethically acceptable.
Expectation of real uncertainty on the part of the investigator regarding the comparative therapeutic merits of each arm in a trial.
Also called therapeutic equipoise.
Principle of being fair to all, with reference to a defined and recognized set of values.
The absence of avoidable or remediable differences among populations or groups defined socially, economically, demographically, or geographically; thus, health inequities involve more than inequality—-whether in health determinants or outcomes, or in access to the resources needed to improve and maintain health—-but also a failure to avoid or overcome such inequality that infringes human rights norms or is otherwise unfair.
Fairness in the allocation of resources or treatments among different individuals or groups.
Equity is about “fairness”. It is often confused with equality, or “the state of being equal”. Fairness and being equal are not necessarily the same things. Inequality can be fair if there are differences in need, or differences in contribution, effort or deserve. The reason we are interested in equity is the same as for efficiency—that is, scarcity. If resources were not scarce, it would be fair for people to consume as much as they want or need of any particular commodity, including health care. However, because of scarcity, we have to judge what a fair allocation might be. In health care, there are two general equity concepts to consider, both dating from the time of Aristotle, namely horizontal equity and vertical equity.
Equity in health implies that everyone should have a fair opportunity to attain his or her full health opportunity, and that no one should be disadvantaged from achieving this potential.
The absence of systematic differences in one or more aspects of health status across socially, demographically, or geographically defined population groups.
Trial that estimates treatment effects that exclude any patient-important superiority of interventions under evaluation. Equivalence trials require a priori definition of the smallest difference in outcomes between these interventions that patients would consider large enough to justify a preference for the superior intervention (given the intervention's harms and burdens). The confidence interval for the estimated treatment effect at the end of the trial should exclude that difference for the authors to claim equivalence (i.e., the confidence limits should be closer to zero than the minimal patient-important difference). This level of precision often requires investigators to enroll large numbers of patients with large numbers of events. Equivalence trials are helpful when investigators want to see whether a cheaper, safer, simpler (or increasingly often, better method to generate income for the sponsor) intervention is neither better nor worse (in terms of efficacy) than a current intervention. Claims of equivalence are frequent when results are not significant, but one must be alert to whether the confidence intervals exclude differences between the interventions that are as large as or larger than those patients would consider important. If they do not, the trial is indeterminate rather than yielding equivalence.
A trial designed to determine whether the response to two or more treatments differs by an amount that is clinically unimportant. This is usually demonstrated by showing that the true treatment difference is likely to lie between a lower and an upper equivalence level of clinically acceptable differences.
A short piece of writing which is quite often written from an author's personal point of view.
Essays [MeSH - publication type]: works consisting of collections of papers or interpretive literary compositions not previously published.
Documents that individually and collectively permit evaluation of the conduct of a study and the quality of the data produced.
Those drugs that satisfy the health care needs of the majority of the population; they should therefore be available at all times in adequate amounts and in appropriate dosage forms, at a price the community can afford.
Essential medicines are those that satisfy the priority health care needs of the population.
Drugs considered essential to meet the health needs of a population as well as to control drug costs.
Also called essential medicines.
Each developing country should establish and strengthen an appropriate health research base to understand its own problems, improve health policy and management, enhance the effectiveness of limited resources, foster innovation and experimentation, and provide the foundation for a stronger developing country voice in setting international priorities.
The observed relationship between an intervention and an outcome expressed as, for example, a number needed to treat to benefit, odds ratio, risk difference, risk ratio, standardized mean difference, or weighted mean difference. (Also called treatment effect.)
The estimated total number of deaths in a population of a given sex and/or age, divided by the total number of this population, expressed per 100,000 population, for a given year, in a given country, territory, or geographic area.
Independent review of the scientific merit and implications of a study regarding the dignity, rights, safety, and wellbeing of research participants.
A formal process of examination of patient care or research proposals for conformity with ethical standards. The review is usually conducted by an organized clinical or research ethics committee, sometimes by a subset of such a committee, an ad hoc group, or an individual ethicist.
An ethicist is one whose judgment on ethics and ethical codes has come to be trusted by a specific community, and (importantly) is expressed in some way that makes it possible for others to mimic or approximate that judgement.
Persons trained in philosophical or theological ethics who work in clinical, research, public policy, or other settings where they bring their expertise to bear on the analysis of ethical dilemmas in policies or cases.
A philosophical discipline concerned with understanding how human beings should act, what is good, and what kind of life is best.
The philosophy or code pertaining to what is ideal in human character and conduct. Also, the field of study dealing with the principles of morality.
Committees established by professional societies, health facilities, or other institutions to consider decisions that have bioethical implications. The role of these committees may include consultation, education, mediation, and/or review of policies and practices. Committees that consider the ethical dimensions of patient care are ethics committees, clinical; committees established to protect the welfare of research subjects are ethics committees, research.
Services provided by an individual ethicist (ethicists) or an ethics team or committee (ethics committees, clinical) to address the ethical issues involved in a specific clinical case. The central purpose is to improve the process and outcomes of patients' care by helping to identify, analyze, and resolve ethical problems.
The project either solely targeted other ethnic groups or included them specifically in the intervention.
A group of people whose members identify with each other, through a common heritage that is real or assumed.
A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.
The cultural practices, language, cuisine, and traditions — not biological or physical differences — used to distinguish groups of people.
The study of the cause or origin of a disease.
Used with diseases for causative agents including microorganisms and includes environmental and social factors and personal habits as contributing factors. It includes pathogenesis.
Evaluability assessment is a systematic process to check whether or not a program is logically theorized, planned, and resourced, and sufficiently well implemented, before the conduct of an impact or outcome evaluation.
Disease that cannot be measured directly by the size of the tumor but can be evaluated by other methods specific to a particular clinical trial.
Patients whose response to a treatment can be measured because enough information has been collected.
The systematic assessment of the relevance, adequacy, progress, efficiency, effectiveness and impact of a course of action.
Systematic and scientific collection, processing and analysis of data related to the implementation of an intervention, in order to assess whether the objectives of an intervention have been achieved.
A process that attempts to determine as systematically and objectively as possible the relevance, effectiveness, and impact of activities in the light of their objectives.
The methodology/approach used in the process of evaluation. This includes quantitative methods as well as qualitative approaches.
The planning and design phase. The evaluation of this phase starts, at the latest, when the idea of beginning the intervention becomes concrete. This is the time when objectives and methods are chosen. The evaluation of the program planning reflects the process of defining the problem, the need for intervention, the target population and the objectives. Furthermore, it includes the evaluation of the resources, and ends with planning for further evaluation.
Human and financial resources used to perform the evaluation.
Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, clinical trials as topic; drug evaluation; and drug evaluation, preclinical are available (MeSH).
Evaluation studies [MeSH - publication type]: works consisting of studies determining the effectiveness or utility of processes, personnel, and equipment.
Technical resources and specific instruments used to perform the evaluation.
The occurrence of a dichotomous outcome that is being sought in the study (such as myocardial infarction, death, or a four-point improvement in pain score).
Proportion or percentage of study participants in a group in which an event is observed. Control event rate (CER) and experimental event rate (EER) are used to refer to event rates in control groups and experimental groups of study participants, respectively.
Evidence comprises the interpretation of empirical data derived from formal research or systematic investigations, using any type of science or social science method.
Facts or testimony in support of a conclusion, statement or belief.
Evidence-based guidelines (EBG) is the practice of evidence-based medicine at the organizational or institutional level. This includes the production of guidelines, policy, and regulations. This approach has also been called evidence based healthcare.
Clinicians who can, in a sophisticated manner, independently find, appraise, and judiciously apply the best evidence to patient care.
Extends the application of the principles of evidence-based medicine to all professions associated with health care, including purchasing and management.
Evidence-based health care is the conscientious use of current best evidence in making decisions about the care of individual patients or the delivery of health services. Current best evidence is up-to-date information from relevant, valid research about the effects of different forms of health care, the potential for harm from exposure to particular agents, the accuracy of diagnostic tests, and the predictive power of prognostic factors.
The use of information derived from formal research and systematic investigation to identify causes and contributing factors to health needs and the most effective health promotion actions to address these in given contexts and populations.
Evidence-based individual decision (EBID) making is evidence-based medicine as practiced by the individual health care provider.
A form of medical ethics that uses knowledge from ethical principles, legal precedent, and evidence-based medicine to draw solutions to ethical dilemmas in the health care field. Sometimes this is also referred to as argument-based medical ethics.
Evidence-based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.
Evidence-based medicine (EBM) aims to apply the best available evidence gained from the scientific method to medical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments (including lack of treatment) and diagnostic tests.
An approach of practicing medicine with the goal to improve and evaluate patient care. It requires the judicious integration of best research evidence with the patient's values to make decisions about medical care. This method is to help physicians make proper diagnosis, devise best testing plan, choose best treatment and methods of disease prevention, as well as develop guidelines for large groups of patients with the same disease.
Evidence-based nursing or EBN is a type of evidence-based medicine. It involves identifying solid research findings and implementing them in nursing practices, in order to increase the quality of patient care.
A way of providing nursing care that is guided by the integration of the best available scientific knowledge with nursing expertise. This approach requires nurses to critically assess relevant scientific data or research evidence, and to implement high-quality interventions for their nursing practice.
Policy making is evidence based when practice policies (e.g., use of resources by clinicians), service policies (e.g., resource allocation, pattern of services), and governance policies (e.g., organizational and financial structures) are based on research evidence of benefit or cost-benefit.
The conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. Evidence-based clinical practice (or evidence-based health care) requires integration of individual clinical expertise and patient preferences with the best available external clinical evidence from systematic research, and consideration of available resources.
A way of providing health care that is guided by a thoughtful integration of the best available scientific knowledge with clinical expertise. This approach allows the practitioner to critically assess research data, clinical guidelines, and other information resources in order to correctly identify the clinical problem, apply the most high-quality intervention, and re-evaluate the outcome for future improvement.
Clinicians who can differentiate evidence-based summaries and recommendations from those that are not evidence-based and understand results sufficiently well to apply them judiciously in clinical care, ensuring decisions are consistent with patients’ values and preferences.
Public health endeavor in which there is an informed, explicit, and judicious use of evidence that has been derived from any of a variety of science and social science research and evaluation methods.
Refers to the process of critically appraising evaluation research and summarizing the findings, with the purpose of answering a specified review question.
Mortality above what would be expected based on the non-crisis mortality rate in the population of interest. Excess mortality is thus mortality that is attributable to the crisis conditions. It can be expressed as a rate (the difference between observed and non-crisis mortality rates), or as a total number of excess deaths.
The characteristics that render potential subjects ineligible to participate in a particular study or that render studies ineligible for inclusion in a systematic review.
Proportion of infants 0–5 months of age who are fed exclusively with breast milk.
Refers to any of the FDA procedures, such as compassionate use, parallel track, and treatment IND that distribute experimental drugs to participants who are failing on currently available treatments for their condition and also are unable to participate in ongoing clinical trials.
A way to provide an investigational therapy to a patient who is not eligible to receive that therapy in a clinical trial, but who has a serious or life-threatening illness for which other treatments are not available. Expanded access allows a patient to receive promising but not yet fully studied or approved therapies when no other treatment option exists. Also called compassionate use trial.
In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational.
A drug that is not FDA licensed for use in humans, or as a treatment for a particular condition.
A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. A drug may be approved by the FDA for use in one disease or condition but be considered experimental or investigational in other diseases or conditions. Also called investigational drug.
In epidemiology and biostatistics, the experimental event rate (EER) is a measure of how often a particular statistical event (such as response to a drug, adverse event or death) occurs within the experimental group (non-control group) of an experiment.
An intervention under evaluation. In a controlled trial, an experimental intervention arm is compared with one or more control arms, and possibly with additional experimental intervention arms.
A study in which the investigators actively intervene to test a hypothesis. In a controlled trial, one type of experiment, the people receiving the treatment being tested are said to be in the experimental group or arm of the trial.
A study in which the investigator specifies the exposure category for each individual (clinical trial) or community (community trial), then follows the individuals or community to detect the effects of the exposure.
A therapeutic alternative to standard or control therapy, which is often a new intervention or different dose of a standard drug.
Expert opinion usually refers to the views of professionals who have expertise in a particular form of practice or field of inquiry, such as clinical practice or research methodology. Expert opinion may refer to one person’s views or to the consensus view of a group of experts.
Presentation of pertinent data by one with special skill or knowledge representing mastery of a particular subject.
Also called expert testimony.
A trial that aims to test a treatment policy in an ideal situation where patients receive the full course of therapy as prescribed, and use of other treatments may be controlled or restricted.
A group whose members have been exposed to a supposed cause of disease or health state of interest, or possess a characteristic that is a determinant of the health outcome of interest.
A condition to which patients are exposed (either a potentially harmful agent or a potentially beneficial one) that may have an impact on their health.
Exposure assessment identifies the specific agent(s), determines the route of exposure, and quantifies the amount and duration of exposure.
Collection, analysis‚ and interpretation of data conducted by an individual or organization outside the organization being evaluated.
External resources for health expressed as a percentage of total expenditure on health.
The extent to which results provide a correct basis for generalizations to other circumstances. For instance, a meta-analysis of trials of elderly patients may not be generalizable to children. (Also called generalizability or applicability.)
A study is externally valid or generalizable if it can produce unbiased inferences regarding a target population (beyond the subjects in the study). This aspect of validity is only meaningful with regard to a specified external target population. For example, the results of a study conducted using only white male subjects might or might not be generalizable to all human males (the target population consisting of all human males). It is not generalizable to females (the target population consisting of all people).
The result of an activity that causes incidental benefits (desirable effects) or damages (costs, pollution) to others with no corresponding compensation provided or paid by those who generate the externality.
Outside (the walls or boundaries of) a community or institution. Refers to ‘external’ sources of support (such as funding) as opposed to ‘internal’ (intramural) support.
Mathematical attempt to extend the findings of a mortality study to a population and/or period that was not represented by the sample.
Birth weight less than 1,000 grams.
An infant whose weight at birth is less than 1,000 grams (2.2 lbs), regardless of gestational age.
A live birth or stillbirth that takes place after at least 20 but less than 28 completed weeks of gestational age. Table of contents:
A trial design used to assess the individual contribution of treatments given in combination, as well as any interactive effect they may have. Most trials only consider a single factor, where an intervention is compared with one or more alternatives, or a placebo. In a trial using a 2x2 factorial design, participants are allocated to one of four possible combinations. For example in a 2x2 factorial RCT of nicotine replacement and counseling, participants would be allocated to: nicotine replacement alone, counseling alone, both, or neither. In this way it is possible to test the independent effect of each intervention on smoking cessation and the combined effect of (interaction between) the two interventions. This type of study is usually carried out in circumstances where no interaction is likely.
Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from databases, bibliographic which is restricted to collections of bibliographic references.
The minimum number of undetected studies with negative results that would be needed to change the conclusions of a meta-analysis. A small fail-safe N suggests that the conclusion of the meta-analysis may be susceptible to publication bias.
Wikipedia A falsely drawn negative conclusion. In diagnostic tests: a conclusion that a person does not have the disease or condition being tested, when they actually do. In clinical trials.
The proportion of negative tests among people with the disease of the condition. It is typically expressed as a conditional probability or a percentage. For instance, mammography screening has a false negative rate of 5 to 20% depending on age, that is, 5 to 20% of women with breast cancer receive a negative test result. The false negative rate and the sensitivity (hit rate) of a test add up to 100%. The false negative rate and the false positive rate are dependent: to decrease one is to increase the other.
Negative test results in subjects who possess the attribute for which the test is conducted. The labeling of diseased persons as healthy when screening in the detection of disease.
A falsely drawn positive conclusion. In diagnostic tests: a conclusion that a person does have the disease or condition being tested, when they actually do not. In clinical trials.
The proportion of positive tests among people without the disease or condition. It is typically expressed as a conditional probability or a percentage. For instance, if mammography screening has a false positive rate of 5 to 10% depending on age, that is 5 to 10% of women without breast cancer nevertheless receive a positive test result. The false positive rate and the specificity (power) of a test add up to 100%. The false positive rate and the false negative rate are dependent: to decrease one is to increase the other.
Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease.
Usually two or more persons living together and related by birth, marriage, or adoption. Families may consist of siblings or other relatives as well as married couples and any children they have.
A social group consisting of parents or parent substitutes and children.
Size and composition of the family.
The health status of the family as a unit including the impact of the health of one member of the family on the family as a unit and on individual family members; also, the impact of family organization or disorganization on the health status of its members.
The conscious effort of couples to regulate the number and spacing of births through artificial and natural methods of contraception. Family planning connotes conception control to avoid pregnancy and abortion, but it also includes efforts of couples to induce pregnancy.
A course or method of action selected, usually by a government, to guide and determine present and future decisions on population control by limiting the number of children or controlling fertility, notably through family planning and contraception within the nuclear family.
Health care programs or services designed to assist individuals in the planning of family size. Various methods of contraception can be used to control the number and timing of childbirths.
A medical specialty concerned with the provision of continuing, comprehensive primary health care for the entire family.
Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from death, the physiological cessation of life and from mortality, an epidemiological or statistical concept.
A feasibility study is an evaluation of a proposal designed to determine the difficulty in carrying out a designated task.
Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.
The probability of conception per menstrual cycle or monthly probability of conception for a sexually active couple not using birth control.
The physiological capacity of a woman to produce a child.
The impact of performance evaluations on clinicians’ behavior.
The improvement seen in medical decision because of performance evaluation and feedback.
Female genital cutting (FGC), also known as female genital mutilation (FGM), female circumcision, or female genital mutilation/cutting (FGM/C), is any procedure involving the partial or total removal of the external female genitalia or other injury to the female genital organs whether for cultural, religious or other non-therapeutic reasons.
A general term encompassing three types of excision of the external female genitalia - Sunna, clitoridectomy, and infibulation. It is associated with severe health risks and has been declared illegal in many places, but continues to be widely practiced in a number of countries, particularly in Africa.
The actual reproductive performance of an individual, a couple, a group, or a population.
The capacity to conceive or to induce conception. It may refer to either the male or female.
The penetration of the ovum by the spermatozoon and combination of their genetic material resulting in the formation of a zygote.
The fusion of a spermatozoon (spermatozoa) with an ovum thus resulting in the formation of a zygote.
Death prior to the complete expulsion or extraction from its mother of a product of fertilization, at or after 20 completed weeks of gestational age. The death is indicated by the fact that, after such separation, the fetus does not breathe or show any other evidence of life such as heart beat, umbilical cord pulsation, or definite movement of voluntary muscles.
The basic WHO definition of fetal death is the intrauterine death of any conceptus at any time during pregnancy. However, for practical purposes, legal definitions usually require recorded fetal deaths to attain some gestational age (16, 20, 22, 24, or 28 weeks) or birth weight (350, 400, 500, or 1000 g). In the United States, there are eight different definitions by combinations of gestational age and weight, and at least as many in Europe.
Death of the developing young in utero. Birth of a dead fetus is stillbirth.
A measure of fetal mortality that compares the number of fetal deaths (stillbirths) with the number of live births over a given period of time.
Number of fetal deaths with stated or presumed gestation of 20 weeks or more in a given population. Late fetal mortality is death after of 28 weeks or more.
The number of fetal deaths divided by the total number of fetal deaths and live births (expressed per 1,000).
Also called stillbirth mortality rate.
Experimentation on, or using the organs or tissues from, a human or other mammalian conceptus in the postembryonic period, after the major structures have been outlined. In humans, this corresponds to the period from the third month after fertilization until birth.
The potential of the fetus to survive outside the uterus after birth, natural or induced. Fetal viability depends largely on the fetal organ maturity, and environmental conditions.
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth. In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.
The product of fertilization from completion of embryonic development, at eight completed weeks after fertilization, until abortion or birth.
The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after conception until birth, as distinguished from the earlier embryo, mammalian.
Fidelity of implementation refers to the degree to which teachers and other program providers implement programs as intended by the program developers.
Field work is a general descriptive term for the collection of raw data.
In public health the use of the term field work refers to epidemiology or the study of epidemics through the gathering of data about the epidemic (such as the pathogen and vector(s) as well as social or sexual contacts, depending upon the situation).
In survey research, field work refers to face-to-face or telephone interviewing.
Research done in the real world (i.e. not in a laboratory).
Term coined by Rosenthal to mean the number of statistically non-significant studies (p > 0.05) that remain unpublished.
Also called file drawer effect.
Any process by which financial resources flow from a third-party payer (e.g., government, insurer, etc.) through the health care organization to the individual clinical provider.
The beginning third of a human pregnancy, from the first day of the last normal menstrual period (menstruation) through the completion of 14 weeks (98 days) of gestation.
The costs associated with operating a particular program or intervention that do not vary with the scale of provision such as the number of patients treated or the number of tests performed. Fixed costs are only “fixed” in the short-term. For example, the building in which a program is housed would be regarded as a fixed cost initially because small changes in the number of patients treated could be accommodated within the existing space. As the time frame increased, so it would be possible to increase capacity by new construction or reduce it by selling assets or finding alternative uses for them, at which point the cost would become variable.
In meta-analysis: a model that calculates a pooled effect estimate using the assumption that all observed variation between studies is caused by the play of chance. Studies are assumed to be measuring the same overall effect. An alternative model is the random-effects model.
Any statistical model assuming homogeneity of effects across the studies being combined—that is, the true effect size has a common true value for all studies. In the summary estimate the variance of each study is taken into account only.
Ability of the surveillance system to adapt to changing needs, incorporate new diseases, leave out less important diseases, change reporting frequency, change or modify data source.
A small group of individuals (typically gatherings of four to eight people with similar background or experience) who meet together and are asked questions by a moderator about a given topic.
A method of data collection and a qualitative research tool in which a small group of individuals are brought together and allowed to interact in a discussion of their opinions about topics, issues, or questions.
A method of qualitative research used when information and insights will be better gained from the interaction of a group than from in-depth interviews with individuals.
A qualitative method to obtain in-depth information on concepts and perceptions about a certain topic through spontaneous group discussion of approximately 6–12 persons, guided by a facilitator.
Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.
The observation over a period of time of study/trial participants to measure outcomes under investigation.
Expected program outcomes are measured after the intervention has been implemented and are not compared to the results of some baseline assessment.
The investigators are aware of the outcome in every patient who participated in a study.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
A format for closed-response questions used to elicit attitudes of the respondents to a certain statement. The respondent choices are limited to four: strongly agree, agree, disagree and strongly disagree. This format, different from the Likert format, does not allow an undecided answer.
The process of making statements about events whose actual outcomes (typically) have not yet been observed.
The prediction or projection of the nature of future problems or existing conditions based upon the extrapolation or interpretation of existing scientific data or by the application of scientific methodology.
A graphical representation of the individual results of each study included in a meta-analysis together with the combined meta-analysis result. The plot also allows readers to see the heterogeneity among the results of the studies. The results of individual studies are shown as squares centered on each study’s point estimate. A horizontal line runs through each square to show each study’s confidence interval - usually, but not always, a 95% confidence interval. The overall estimate from the meta-analysis and its confidence interval are shown at the bottom, represented as a diamond. The centre of the diamond represents the pooled point estimate, and its horizontal tips represent the confidence interval.
Formative evaluation is a method of judging the worth of a program while the program activities are forming or happening. Formative evaluation focuses on the process. Example: collecting continuous feedback from participants in a program in order to revise the program as needed.
Formative evaluation refers to the program planners’ use of data from process evaluation that has been conducted early in the development of an intervention, so that adjustments to the program can be made if necessary.
Lists of drugs or collections of recipes, formulas, and prescriptions for the compounding of medicinal preparations. Formularies differ from pharmacopoeias in that they are less complete, lacking full descriptions of the drugs, their formulations, analytic composition, chemical properties, etc. In hospitals, formularies list all drugs commonly stocked in the hospital pharmacy.
Formularies [MeSH - publication type]: works that consist of lists of drugs or collections of recipes, formulas, and prescriptions for the compounding of medicinal preparations.
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
A phenomenon that is observed when a small subgroup of a larger population establishes itself as a separate and isolated entity. The subgroup's gene pool carries only a fraction of the genetic diversity of the parental population resulting in an increased frequency of certain diseases in the subgroup, especially those diseases known to be autosomal recessive.
Scientific fraud is deliberate deception and may take the form of fabricating data, inventing patients, or manipulating data to provide a desired answer.
Exploitation through misrepresentation of the facts or concealment of the purposes of the exploiter.
A number of observations in a class of events. Frequencies can be expressed as relative frequencies, absolute frequencies, or natural frequencies.
The way in which scores within a given sample are distributed.
A complete summary of the frequencies of the values or categories of a variable; often displayed in a two column table: the left column lists the individual values or categories, the right column indicates the number of observations in each category.
A graphic method for summarizing data and looking at them, in which each variable is plotted against the frequency with which it is found.
A table that gives the frequency with which a particular value appears in the data.
A graph of a frequency distribution with values of the variable on the x-axis and the number of observations on the y-axis; data points are plotted at the midpoints of the intervals and are connected with a straight line.
Statistical methods, such as significance tests and confidence intervals, which can be interpreted in terms of the frequency of certain outcomes occurring in hypothetical repeated realizations of the same experimental situation.
The set of subjects that is as close as possible to the ideal implied by the intention-to- treat principle. It is derived from the set of all randomized subjects by minimal and justified elimination of subjects.
The capacity to engage in activities of daily living and social role activities. (Increasingly, functional status is considered to represent the concept of “health” in its behavioral manifestations.
Providing health care organizations with the financial resources required to carry out a general range of health-related activities.
A graphical display of some measure of study precision plotted against effect size that can be used to investigate whether there is a link between study size and treatment effect. One possible cause of an observed association is reporting bias.
A graphical method to display possible publication bias. It shows the relation between the effect size of study and the size of the same study, which can be measured in different ways (standard error of the effect size, its inverse, sample size, or the number of effects observed in a study). If there is no publication bias, a typical symmetric funnel shape can be observed.
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A primary care physician/general practitioner (or another provider) who is responsible for overseeing and coordinating all the medical needs of a patient. The gatekeeper must authorize any referral of the patient to a specialist or hospital.
Gender is a dynamic concept, which looks at the interrelationship between men and women in the context of their society and roles in that society. Gender roles are defined as the social and cultural traits that different societies assign to males and females. Such gender roles are the patterns of behavior, rights and obligations defined by a society as appropriate for each sex. A gender perspective is a way of looking at situations and issues taking into account the respective roles and contributions of men and women in society.
Gender identity (otherwise known as core gender identity) is the gender(s), or lack thereof, a person self-identifies as. It is not necessarily based on biological fact, either real or perceived, nor is it always based on sexual orientation.
A person's concept of self as being male and masculine or female and feminine, or ambivalent, based in part on physical characteristics, parental responses, and psychological and social pressures. It is the internal experience of gender role.
The estimated total number of deaths in a population of a given sex, divided by the total number of that population after removing the effect of differences in the age distribution, expressed per 100,000 population, for a given year, in a given country, territory, or geographic area.
The number of live births per 1,000 women ages 15-44 or 15-49 years in a given year.
General government expenditure on health (GGHE) comprises the direct outlays earmarked for the enhancement of the health status of the population and/or the distribution of medical-care goods and services in the population by the following financing agents: central/federal, state/provincial/regional, and local/municipal authorities; extrabudgetary agencies, social security schemes; parastatals. All can be financed through domestic funds or through external resources.
Level of general government expenditure on health (GGHE) expressed as a percentage of total expenditure on health (THE).
Level of general government expenditure on health (GGHE) expressed as a percentage of total government expenditure.
The extent to which the findings of a clinical trial can be reliably extrapolated from the subjects who participated in the trial to a broader patient population and a broader range of clinical settings.
Generalizability is the degree to which the results of a study or systematic review can be extrapolated to other circumstances, in particular to routine health-care situations.
The procedure used to obtain the (random) sequence for making intervention assignments, such as use of a table of random numbers or a computerized random-number generator. Options such as simple randomization, blocked randomization, and stratified randomization are part of the generation of the allocation sequence.
Drugs which are identical in chemical composition to a brand name pharmaceutical preparation, but produced by competitors after the firm’s patent expires.
A pharmaceutical product, usually intended to be interchangeable with an innovator product, that is manufactured without a license from the innovator company and marketed after the expiry date of the patent or other exclusive rights.
Drugs whose drug name is not protected by a trademark. They may be manufactured by several companies.
Generic health-related quality of life (HRQL) measures contain items covering all relevant areas of HRQL. They are designed for administration to people with any kind of underlying health problem (or no problem at all). Generic HRQL measures allow comparisons across diseases or conditions.
Genetic epidemiology is the study of the role of genetic factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors.
Research into the cause, transmission, amelioration, elimination, or enhancement of inherited disorders and traits.
The geometric mean, in mathematics, is a type of mean or average, which indicates the central tendency or typical value of a set of numbers.
The mean or average of a set of data measured on a logarithmic scale.
Age of an embryo or fetus calculated by adding 2 weeks (14 days) to the number of completed weeks since fertilization. Note: for frozen/thawed embryo transfers, an estimated date of fertilization is computed by subtracting the embryo age at freezing from the transfer date of the FET cycle.
The duration of pregnancy (and thus the age of fetus), measured from the first day of the last normal menstrual period or LMP. While it is the most practical basis for dating pregnancy, the LMP in fact occurs two or more weeks before conception. The LMP based gestational age is sometimes adjusted later during pregnancy on the basis of ultrasound examination.
The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization.
A single variable, usually a scale of ordered categorical ratings, which integrates objective variables and the investigator's overall impression about the state or change in state of a subject.
Refers to a WHO and World Bank study published in the World Development Report 1993 that measured the total loss of health resulting from diseases and injuries. Updated in 1996 and again in 2000, the study generates the most comprehensive and consistent set of estimates of mortality and morbidity by age, sex and region. The original report showed that infectious disease accounts for 43% of the global burden.
Global health refers to the transnational impacts of globalization upon health determinants and health problems which are the beyond the control of individual nations.
Goal free evaluation is an assessment of all program effects, whether or not they are part of the intended objectives or goals.
The method, procedure, or measurement that is widely accepted as being the best available, against which new developments should be compared.
Standard for clinical studies which encompasses the design, conduct, monitoring, termination, audit, analyses, reporting and documentation of the studies and which ensures that the studies are scientifically and ethically sound and that the clinical properties of the pharmaceutical product under investigation are properly documented.
A standard for the design, conduct, performance, monitoring, auditing, recording, analyses, and reporting of clinical trials that provides assurance that the data and reported results are credible and accurate, and that the rights, integrity, and confidentiality of trial subjects are protected.
Programs and activities sponsored or administered by local, state, or national governments.
Government publications [MeSH - publication type]: works consisting of documents issued by local, regional, or national governments or by their agencies or subdivisions.
The ability to secure grants to support research projects.
Number of previous pregnancies (as distinguished from parity, the number of previous births).
The number of pregnancies, complete or incomplete, experienced by a female. It is different from parity, which is the number of offspring borne.
Grey literature is the kind of material that is not published in easily accessible journals or databases. It includes things like conference proceedings that include the abstracts of the research presented at conferences, unpublished theses, and so on.
Total number of pupils or of a given sex enrolled in primary education, regardless of age, expressed as a percentage of the corresponding population of the age group, which officially corresponds to primary schooling, at a specific period of time, usually a year, for a given country, territory, or geographic area. According to the 1997 International Standard Classification of Education (ISCED-97), adopted by UNESCO, primary education is defined as the level of education which the main function is to provide the basic elements of education at such establishments as elementary schools, and primary schools.
The average number of daughters that would be born alive to a woman (or group of women) during her lifetime if she passed through her childbearing years conforming to the age-specific fertility rates of a given year.
Any group of three or more full-time physicians organized in a legally recognized entity for the provision of health care services, sharing space, equipment, personnel and records for both patient care and business management, and who have a predetermined arrangement for the distribution of income.
The number of people added to (or subtracted from) a population in a year due to natural increase and net migration expressed as a percentage of the population at the beginning of the time period.
Guidance is information or counseling as to how or where a particular disease or situation can be handled. Guidance can be given orally, in written documents or through the media (television, internet, videos). In clinical practice the purpose of guidance is to help people make their own decisions based on their values. Within health care the purpose of guidance is to instruct the healthcare providers in the optimal use of resources.
Guidelines are systematically developed statements to assist practitioner and patient decisions about appropriate interventions for specific circumstances. Guidelines often include a set of recommendations or steps that can be followed when implementing an intervention. The content of guidelines are commonly based on available research evidence. Other terms used for guidelines: practice guidance, clinical guidelines, guides, practice recommendations.
Recommendations or suggestions for organizing or delivering services of various types. Guidelines are distinguished from regulations by their voluntary nature, but adherence is generally facilitated by professional expectations rather than formal requirements. Guidelines for public health activities, such as those for laboratory standards, are distinguished from clinical guidelines, which describe interventions that are indicated (or not indicated) in the diagnosis and management of specific diseases or conditions. Increasingly, the development of clinical guidelines is informed by scientific evidence of the benefit of the recommended procedures, thus giving rise to the field known as “evidence-based medicine”. The development of administrative guidelines is more often based on evidence from practice of systematically poor quality when certain structural elements of health systems are not appropriately or adequately maintained.
Guideline [MeSH - publication type]: works consisting of a set of statements, directions, or principles presenting current or future rules or policy. Guidelines may be developed by government agencies at any level, institutions, organizations such as professional societies or governing boards, or by the convening of expert panels. The text may be cursive or in outline form, but it is generally a comprehensive guide to problems and approaches in any discipline or activity. This concept relates to the general conduct and administration of health care activities rather than to specific decisions for a particular clinical condition. For that aspect, practice guideline is available. Table of contents:
A type of reference work, or other collection of instructions, that is intended to provide ready reference.
Handbooks [publication type]: works consisting of concise reference works in which facts and information pertaining to a certain subject or field are arranged for ready reference and consultation rather than for continuous reading and study.
Harm reduction, or harm minimization, refers to a range of public health policies designed to reduce the harmful consequences associated with recreational drug use and other high risk activities.
The application of methods designed to reduce the risk of harm associated with certain behaviors without reduction in frequency of those behaviors. The risk-associated behaviors include ongoing and active addictive behaviors.
Evidence-based healthcare resources often have great difficulty in providing good quality evidence on harms. Most RCTs are not designed to assess harms adequately: the sample size is too small, the trial too short, and often information on harms is not systematically collected. Often a lot of the harms data are in the form of uncontrolled case reports. Comparing data from these series is fraught with difficulties because of different numbers receiving the intervention, different baseline risks and differential reporting. We aim to search systematically for evidence on what are considered the most important harms of an intervention. The best evidence is from a systematic review of harms data that attempts to integrate data from different sources. However, because of these difficulties and following the maxim "first one must not do harm" we accept weaker evidence in the Harms than in the Benefits section. This can include information on whether the intervention has been either banned or withdrawn because of the risk of harms.
An effect which results in the improvement of subjects’ performances through being observed and/or social contact. It is an example of a placebo effect.
A situation that poses a level of threat to life, health, property, or environment.
A possible threat of source of exposure to injury, harm or loss, e.g. conflict, natural phenomena.
Hazard identification involves identifying the types of health effect that a particular exposure can cause.
The probability of an event occurring given that it hasn’t occurred up to the current point in time.
A measure of effect produced by a survival analysis. This represents the increased risk with which one group is likely to experience the outcome of interest. For example, if the hazard ratio for death for a treatment is 0.5, then we can say that treated patients are likely to die at half the rate of untreated patients.
A health care provider or health professional is an organization or person who delivers proper health care in a systematic way professionally to any individual in need of health care services.
Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. (World Health Organization definition).
The state of the organism when it functions optimally without evidence of disease.
In health economics, a health benefit is one which is recognized as providing a gain in terms of reduced costs or increased health.
Any type of services provided by professionals or paraprofessionals with an impact on health status.
Someone who uses, is affected by, or who is entitled to use a health related service.
Health care resources that are consumed. These reflect the inability to use the same resources for other worthwhile purposes (opportunity costs).
The actual costs of providing services related to the delivery of health care, including the costs of procedures, therapies, and medications. It is differentiated from health expenditures, which refers to the amount of money paid for the services, and from fees, which refers to the amount charged, regardless of cost.
Methods and techniques used in evaluating the quality of health care, its planning, and delivery.
Healthcare inequality (also called health disparities in some countries) refers to the disparities in the access to adequate healthcare between different gender, race, and socioeconomic groups.
Health disparities (also called healthcare inequality in some countries) refer to gaps in the quality of health and health care across racial, ethnic, sexual orientation and socioeconomic groups.
Norms, criteria, standards, and other direct qualitative and quantitative measures used in determining the quality of health care.
Planning for the equitable allocation, apportionment, or distribution of available health resources.
Economic sector concerned with the provision, distribution, and consumption of health care services and related products.
Statistical measures of utilization and other aspects of the provision of health care services including hospitalization and ambulatory care.
A formal structure for a defined population, whose finance, management, scope and content is defined by law and regulations. It provides for services to be delivered to people to contribute to their health…delivered in defined settings such as homes, educational institutions, workplaces, public places, communities, hospitals and clinics.
A facility that provides (ambulatory) medical and sanitary services to a specific group in a population.
The personal, social, cultural, economic and environmental factors that influence the health status of individuals or populations.
The wide variety of interacting proximate and distal influences on the health of individuals and populations, including but not limited to political contexts, policies, distribution of power and wealth, social and physical and social environments, health systems and services, as well as genetic, biological, and historico-cultural characteristics. The use of the term “determinants” rather than “determinant” is intentional. With the exception of Mendelian dominant disorders (and, even here, their severity might be modifiable by the presence of other factors), there is no single determinant of disease or illness.
Also called determinants of health.
Health economics is a branch of economics concerned with issues related to scarcity in the allocation of health and health care. In broad terms, health economists study the functioning of the health care system and the private and social causes of health-affecting behaviors such as smoking.
The study of how scarce resources are allocated among alternative uses for the care of sickness and the promotion, maintenance and improvement of health, including the study of how health care and health-related services, their costs and benefits, and health itself are distributed among individuals and groups in society.
One role of health economics is to provide a set of analytical techniques to assist decision making, usually in the health care sector, to promote efficiency and equity. Another role, however, is simply to provide a way of thinking about health and health care resource use; introducing a thought process that recognizes scarcity, the need to make choices and, thus, that more is not always better if other things can be done with the same resources. Ultimately, health economics is about maximizing social benefits obtained from constrained health producing resources.
The planned and managed process of investing in education to achieve improvement in health of a population.
Education that increases the awareness and favorably influences the attitudes and knowledge relating to the improvement of health on a personal or community basis.
Health ethics involves a process of systematic and continuous reflection on the norms and values which should guide decisions about health care at the personal, institutional, or societal level, and by which the outcomes of such decisions may be judged.
A population based measure of the proportion of expected life span estimated to be healthful and fulfilling, or free of illness, disease and disability according to social norms and perceptions and professional standards.
The amounts spent by individuals, groups, nations, or private or public organizations for total health care and/or its various components. These amounts may or may not be equivalent to the actual costs (health care costs) and may or may not be shared among the patient, insurers, and/or employers.
Institutions which provide medical or health-related services.
Health financing is the system of fund generation or credit, fund expenditures and flow of funds used to support the health services delivery system.
The attainment by all people of the world of a level of health that will permit them to lead a socially and economically productive life.
An increase in the measured health of an individual or population, including length and quality of life.
Health geography is the application of geographical information, perspectives, and methods to the study of health, disease, and health care.
A combination of procedures, methods and tools by which a policy, program or project may be judged as to its potential effects on the health of a population, and the distribution of those effects within the population.
The overall effects, direct or indirect, of a policy, strategy, program or project on the health of a population.
Health impacts refer to both positive and negative changes in community health that are attributable to a policy, program, or project.
A health indicator is a characteristic of an individual, population, or environment which is subject to measurement (directly or indirectly) and can be used to describe one or more aspects of the health of an individual or population (quality, quantity and time).
A measure that reflects, or indicates, the state of health of persons in a defined population, e.g., the infant mortality rate.
Health inequality is the generic term used to designate differences, variations, and disparities in the health achievements of individuals and groups. A straightforward example of health inequality is higher incidence of disease X in group A as compared with group B of population P. If disease X is randomly or equally distributed among all groups of population P, then there is no presence of health inequality in that population. In other words, health inequality is a descriptive term that need not imply moral judgment.
A health impact assessment (HIA) with the specific aim of assessing the impacts on the health and wellbeing of a proposal on people in the community who are experiencing health and other inequalities in relation to age, sex, ethnic background, and/or socioeconomic status, to identify whether there is a differential distribution of impacts. The current consensus is that all HIAs should consider inequalities and/or the distribution of potential health effects.
Health inequity refers to those inequalities in health that are deemed to be unfair or stemming from some form of injustice.
Health informatics, health care informatics or medical informatics is the intersection of information science, computer science, and health care. It deals with the resources, devices, and methods required to optimize the acquisition, storage, retrieval, and use of information in health and biomedicine. Health informatics tools include not only computers but also clinical guidelines, formal medical terminologies, and information and communication systems. It is applied to the areas of nursing, clinical care, dentistry, pharmacy, public health and (bio)medical research.
A combination of health statistics from various sources, used to derive information about health status, health care, provision and use of services, and impact on health.
The application of information processing involving both computer hardware and software that deals with the storage, retrieval, sharing, and use of health care information, data, and knowledge for communication and decision making.
Average number of years that a person can expect to live in "full health" by taking into account years lived in less than full health due to disease and/or injury.
Health literacy is an individual's ability to read, understand and use healthcare information to make decisions and follow instructions for treatment.
Degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.
WHO Statistical Information System: includes general managers, statisticians, lawyers, accountants, medical secretaries, gardeners, computer technicians, ambulance staff, cleaning staff, building and engineering staff, skilled administrative staff and general support staff.
The availability of health personnel. It includes the demand and recruitment of both professional and allied health personnel, their present and future supply and distribution, and their assignment and utilization.
All possible changes in health status that may occur for a defined population or that may be associated with exposure to an intervention. These include changes in the length and quality of life, major morbid events, and mortality.
Changes in health status (mortality and morbidity) which result from the provision of health (or other) services.
Men and women working in the provision of health services, whether as individual practitioners or employees of health institutions and programs, whether or not professionally trained, and whether or not subject to public regulation.
A broad term for all kinds of public or private schemes of health care coverage, including, for example, national health systems, sickness fund schemes, and private health insurance schemes.
Those actions designed to carry out recommendations pertaining to health plans or programs.
Planning for needed health and/or welfare services and facilities.
A formal statement or procedure within institutions (notably government) which defines priorities and the parameters for action in response to health needs, available resources and other political pressures.
Decisions, usually developed by government policymakers, for determining present and future objectives pertaining to the health care system.
Preferentially rated health-related activities or functions to be used in establishing health planning goals.
A type of data collection tool, intended for use in the entire population (including the healthy, the very sick, and patients with any sort of health problem) that attempts to measure all important aspects of health-related quality of life (HRQL).
The planned and managed process of encouraging and assisting improvement in the health of a population as distinct from the provision of health care services.
Activities, usually directed at individuals, to maximize the development of resilience to a threat or threats to health.
Encouraging consumer behaviors most likely to optimize health potentials (physical and psychosocial) through health information, preventive programs, and access to medical care.
Activities undertaken to reduce the likelihood of occurrence of situations or events that are threats to health and organized on a population level by a societal action (such as a law or regulation) rather than at an individual level.
Measurements of how people are feeling, or the value they place on their health state. Such measurements can be disease specific or generic.
Generally synonymous with “health status” but also encompassing reactions to coping with life circumstances.
The means available for the operation of health systems, including human resources, facilities, equipment and supplies, financial funds and knowledge.
Available manpower, facilities, revenue, equipment, and supplies to produce requisite health care and services.
The health sector is made up of the people, institutions and resources, arranged together in accordance with established policies, whose primary purpose is to promote, restore and maintain health. It includes government ministries and departments, hospitals and other health services, health insurance schemes, voluntary and private organizations in health, as well as the pharmaceutical industry and drug wholesale companies.
Any service which can contribute to improved health or the diagnosis, treatment and rehabilitation of sick people and not necessarily limited to medical or health-care services.
Services for the diagnosis and treatment of disease and the maintenance of health.
The organization and administration of health services dedicated to the delivery of health care.
Excessive or unnecessary utilization of health services by patients or physicians.
Health services required by a population or community as well as the health services that the population or community is able and willing to pay for.
A field on inquiry that examines the impact of the organization, financing and management of health care services on the delivery, quality, cost, access to and outcomes of such services.
The integration of epidemiologic, sociological, economic, and other analytic sciences in the study of health services. Health services research is usually concerned with relationships between need, demand, supply, use, and outcome of health services. The aim of the research is evaluation, particularly in terms of structure, process, output, and outcome.
The health condition of an individual or group over a specified interval of time (commonly assessed at a particular point in time).
Term for the state of health of an individual, group or population measured against defined standards/indicators.
The state of health of a person or population assessed with reference to morbidity, impairments, anthropological measurements, mortality, and indicators of functional status and quality of life.
All aspects of physical and mental health and their manifestations in daily living, including impairment, disability, and handicap. Sometimes other aspects related to vulnerabilities and resiliencies are also included under this definition.
The level of health of the individual, group, or population as subjectively assessed by the individual or by more objective measures.
Variation in rates of disease occurrence and disabilities between socioeconomic and /or geographically defined population groups.
The measurement of the health status for a given population using a variety of indices, including morbidity, mortality, and available health resources.
A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.
The people, institutions and resources, arranged together in accordance with established policies, to improve the health of the population they serve, while responding to people’s legitimate expectations and protecting them against the cost of ill-health through a variety of activities whose primary intent is to improve health.
Essentially, the health system is the health sector categorized (with linkages) according to core functions (financing, provision of inputs and service delivery/coverage), main actors (government and consumers/households) and outcomes (health, fairness in financing and responsiveness.
Health targets state, for a given population, the amount of change (using a health indicator) which could be reasonably expected within a defined period of time.
Any intervention that may be used to promote health, to prevent, diagnose or treat disease, or for rehabilitation or long-term care. This includes pharmaceuticals, devices, procedures and organizational systems used in health care.
The application of technology to the solution of medical problems.
Also called biomedical technology.
Comprehensive evaluation and assessment of existing and emerging medical technologies including pharmaceuticals, procedures, services, devices and equipment in regard to their medical, economic, social and ethical effects.
The systematic evaluation of properties, effects and/or impacts of healthcare technology. It may address the direct, intended consequences of technologies as well as their indirect, unintended consequences. Its main purpose is to inform technology-related policy-making in health care. HTA is conducted by interdisciplinary groups using explicit analytical frameworks drawing from a variety of methods.
Demographic and epidemiologic changes that have occurred in the last five decades in many developing countries and that are characterized by major growth in the number and proportion of middle-aged and elderly persons and in the frequency of the diseases that occur in these age groups. The health transition is the result of efforts to improve maternal and child health via primary care and outreach services and such efforts have been responsible for a decrease in the birth rate; reduced maternal mortality; improved preventive services; reduced infant mortality, and the increased life expectancy that defines the transition.
Is a measure of strength of preference that people have for particular health states. A year in full health is arbitrarily assigned a value of 1: a state that is considered equivalent to death is assigned a value of zero. Health states that lie somewhere between these two anchor points will have a utility value that lies somewhere between zero and one. States considered worse than death will have a negative value. The health utility is used to weight years of life in order to estimate quality adjusted life years.
In a clinical study, a person who does not have the disorder or disease being studied. Results from healthy controls are compared to results from the group being studied.
Used in a general sense to describe the variation in, or diversity of, participants, interventions, and measurement of outcomes across a set of studies, or the variation in internal validity of those studies. Used specifically, as statistical heterogeneity, to describe the degree of variation in the effect estimates from a set of studies. Also used to indicate the presence of variability among studies beyond the amount expected due solely to the play of chance.
Heterogeneity is used generically to refer to any type of significant variability between studies contributing to a meta-analysis that renders the data inappropriate for pooling. This may include heterogeneity in diagnostic procedure, intervention strategy, outcome measures, population, study samples, or study methods. The term heterogeneity can also refer to differences in study findings. Statistical tests can be applied to compare study findings to determine whether differences between the findings are statistically significant.
Used to describe a set of studies or participants with sizeable heterogeneity. The opposite of homogeneous.
Hierarchical regression examines the relation between independent variables or predictor variables (e.g., age, sex, disease severity) and a dependent variable (or outcome variable; e.g., death, exercise capacity). Hierarchical regression differs from standard regression in that one predictor is a subcategory of another predictor. The lower-level predictor is nested within the higher-level predictor. For instance, in a regression predicting likelihood of withdrawal of life support in intensive care units (ICUs) participating in an international study, city is nested within country and ICU is nested within city.
A system of classifying and organizing types of evidence, typically for questions of treatment and prevention. Clinicians should look for the evidence from the highest position in the hierarchy.
A group in the community with an elevated risk of disease.
Pregnancies occurring under the following conditions: too closely spaces, too frequent, mother too young or too old, or accompanied by such high-risk factors as high blood pressure or diabetes.
Pregnancy in which the mother and/or fetus are at greater than normal risk of morbidity or mortality. Causes include inadequate prenatal care, previous obstetrical history (abortion, spontaneous), pre-existing maternal disease, pregnancy-induced disease (gestational hypertension), and multiple pregnancy, as well as advanced maternal age above 35.
A method of plotting frequency distributions.
A graphic representation of the frequency distribution of a continuous variable. Rectangles are drawn in such a way that their bases lie on a linear scale representing different intervals, and their heights are proportional to the frequencies of the values within each of the intervals.
A research study in which the medical records of groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) are compared for a particular outcome. Also called a retrospective cohort study.
Historical article [MeSH - publication type]: An article or portion of an article giving an account of past events or circumstances significant in a field of study, a profession, a discovery, an invention, etc. The concept of history is very wide, ranging from the dawn of time to the present. This publication type is often checked in conjunction with biography.
Cohort studies can be conducted retrospectively (historically) in the sense that someone other than the investigator has followed patients, and the investigator obtains the data base and then examines the association between exposure and outcome.
A control person or group for whom data were collected earlier than for the group being studied. There is a large risk of bias in studies that use historical controls due to systematic differences between the comparison groups, due to changes over time in risks, prognosis, health care, etc.
An individual treated in the past and used in a comparison group when researchers analyze the results of a clinical study that had no control group. The use of a control, or comparison, group helps researchers determine the effects of a new treatment more accurately.
Medical and paramedical services delivered to patients at home.
Community health and nursing services providing coordinated multiple services to the patient at the patient's homes. These home-care services are provided by a visiting nurse, home health agencies, hospitals, or organized community groups using professional staff for care delivery. It differs from home nursing which is provided by non-professionals.
Also called home care services.
Used in a general sense to mean that the participants, interventions, and measurement of outcomes are similar across a set of studies. Used specifically to describe the effect estimates from a set of studies where they do not vary more than would be expected by chance.
Refers to the “equal treatment of equals”. This is embodied in health care objectives such as “equal access for equal need” and is reflected in efforts to use population-based formulas to allocate health resources to geographical regions.
Residential establishment equipped with inpatient facilities for 24-hour medical and nursing care, diagnosis, treatment and rehabilitation of the sick and injured, usually for both medical and surgical conditions, and staffed with at least one physician. The hospital may also provide outpatient services.
Institutions with an organized medical staff which provide medical care to patients.
A regularly maintained and staffed bed for the accommodation and full-time care of a succession of inpatients, situated in wards or areas of the hospital where continuous medical care is provided. It is a measure of hospital capacity.
The number of beds which a hospital has been designed and constructed to contain. It may also refer to the number of beds set up and staffed for use.
The number of hospital beds available per every 10,000 inhabitants in a population.
The number of hospital beds available per every 1,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area.
The expenses incurred by a hospital in providing care. The hospital costs attributed to a particular patient care episode include the direct costs plus an appropriate proportion of the overhead for administration, personnel, building maintenance, equipment, etc. Hospital costs are one of the factors which determine hospital charges (the price the hospital sets for its services).
The number of hospital discharges per every 1,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area. It represents an estimate of the degree of utilization of in-patient health care services. Hospital discharge is defined as the formal release of a hospitalized individual due to conclusion of the hospitalization stay, either by death, return home, or transfer to another institution. A hospital is defined as any medical facility with an organized medical and professional staff and beds available for continuous hospitalization of patients formally admitted to it for medical observation, care, diagnosis, or surgical and non-surgical treatment.
A vital statistic measuring or recording the rate of death from any cause in hospitalized populations.
A person or other living organism that can be infected by an infectious agent under natural conditions.
An intrinsic factor (age, race, sex, behaviors, etc.) which influences an individual's exposure, susceptibility, or response to a causative agent.
One or more persons occupying a housing unit.
The household is the basic residential unit in which economic production, consumption, inheritance, child rearing, and shelter are organized and carried out; the household may or may not be synonymous with family
Human skills and capabilities generated by investments in education and health.
This is a measure, developed by the United Nations Development Programme, which ranks national development based on measures of life expectancy at birth, educational attainment, and adjusted real per capita income. It is designed to give a more holistic view of a country's development status, compared to per capita income (the measure used by the World Bank to rank countries).
The use of humans as investigational subjects.
People who work in the various professions of health care.
Rights and freedoms to which all humans are entitled.
The rights of the individual to cultural, social, economic, and educational opportunities as provided by society, e.g., right to work, right to education, and right to social security.
An individual who is or becomes a participant in research, either as a recipient of the test article or as a control. A subject may be either a healthy human or a patient.
Human subject research includes experiments (formally known as interventional studies) and observational studies. Human subjects are commonly participants in research on basic biology, clinical medicine, psychology, and all other social sciences.
A disease that is constantly present at a high incidence and/or prevalence rate.
An unproved theory that can be tested through research. To properly test a hypothesis, it should be pre-specified and clearly articulated, and the study to test it should be designed appropriately.
A supposition, arrived at from observation or reflection, that leads to refutable predictions. Any conjecture cast in a form that will allow it to be tested and refuted.
A supposition or assumption advanced as a basis for reasoning or argument, or as a guide to experimental investigation.
A statistical procedure to determine whether to reject a null hypothesis on the basis of the observed data. Table of contents:
A measure used to quantify heterogeneity. It describes the percentage of the variability in effect estimates that is due to heterogeneity rather than sampling error (chance). A value greater than 50% may be considered to represent substantial heterogeneity.
An elementary form of innumeracy in which a person does not know, not even roughly, how great a relevant risk is. It differs from the illusion of certainty (for example, smoking cigarettes does not cause lung cancer) in that the person is aware that there are uncertainties, but does not know how great they are.
The belief that an event is absolutely certain although it may not be. For instance, people tend to believe that the results of modern technologies, such as HIV testing, DNA fingerprinting, ordinary fingerprinting techniques, medical tests, or even the mechanical vote-counting machines used in elections are certain, that is, error free. The illusion can have benefits, such as reassurance, but also costs, such as suicide after a false positive HIV test. With respect to morals, religion, and political values, the illusion of certainty may be a requirement for being accepted by a social group, fostering social control.
The total, direct and indirect, effects of a program, service or institution on health status and overall health and socio-economic development.
Impact evaluation assesses the changes that can be attributed to a particular intervention, such as a project, program or policy, both the intended ones, as well as ideally the unintended ones. In contrast to outcome monitoring, which examines whether targets have been achieved, impact evaluation is structured to answer the question: how would participants’ well-being have changed if the intervention had not been undertaken? This involves counterfactual analysis, that is, a comparison between what actually happened and what would have happened in the absence of the intervention.
Impact evaluation examines the initial effect of a program on proximal targets of change, such as policies, behaviors, or attitudes. Thus impact evaluation corresponds to assessment of the initial objectives of the program.
Impact evaluation monitors the acceptance of recommendations and the implementation of recommendations once accepted.
In a given year, the impact factor of a journal is the average number of citations to those papers that were published during the two preceding years. For example, the 2008 impact factor of a journal would be calculated as follows: A = the number of times articles published in 2006 and 2007 were cited by indexed journals during 2008 B = the total number of "citable items" published in 2006 and 2007. ("Citable items" are usually articles, reviews, proceedings, or notes; not editorials or Letters-to-the-Editor.) 2008 impact factor = A/B (Note that 2008 impact factors are actually published in 2009; they cannot be calculated until all of the 2008 publications have been received by the indexing agency.)
A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.
Also called journal impact factor.
A person, who is independent of the trial, who cannot be unfairly influenced by people involved with the trial, who attends the informed consent process if the subject or the subject's legally acceptable representative cannot read, and who reads the informed consent form and any other written information supplied to the subject.
The carrying out of a project or program.
The study of how a specific set of activities and designed strategies effect the integration of evidence-based information and interventions into health care and community health practices.
A quantification of the uncertainty in an estimate such as an effect size. Usually expressed as the 95% confidence interval around the estimate. Also refers more generally to other sources of uncertainty, such as measurement error.
In the laboratory (outside the body). The opposite of in vivo (in the body).
In vitro [MeSH - publication type]: studies using excised tissues.
In the body. The opposite of in vitro (outside the body or in the laboratory).
A designated group of persons assembled at a common time early in the development of a specific clinical disorder (for example, at the time of first exposure to the putative cause or the time of initial diagnosis) and who are followed thereafter.
The number of new cases of a disease diagnosed each year.
The number of new occurrences of something in a population over a particular period of time, e.g. the number of cases of a disease in a country over one year.
The number of instances of illness commencing or of persons falling ill, during a given period in a specified population. More generally, the number of new events, e.g., new cases of a disease in a defined population, within a specified period of time. The term incidence is sometimes used to denote incidence rate.
The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases, new or old, in the population at a given time.
The number of persons contracting a disease per 1,000 population at risk, for a given period of time.
A measure of the frequency with which an event, such as a new case of illness, occurs in a population over a period of time. The denominator is the population at risk; the numerator is the number of new cases occurring during a given time period.
Unanticipated information discovered in the course of testing or medical care. Used in discussions of information that may have social or psychological consequences, such as when it is learned that a child's biological father is someone other than the putative father, or that a person tested for one disease or disorder has, or is at risk for, something else.
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent.
A period of subclinical or inapparent pathologic changes following exposure, ending with the onset of symptoms of infectious disease.
The characteristics that define the population eligible for a study or that define the studies that will be eligible for inclusion in a systematic review.
Occurs when investigators study a diagnostic test that incorporates features of the target outcome. The result is a bias toward making the test appear more powerful in differentiating target positive from target negative than it actually is.
Refers to the process of estimating the additional cost per unit of outcome achieved when comparing one treatment modality to another (typically more expensive and more effective) form of treatment. Where the margin refers strictly to differences in scale within a treatment modality (such as increased throughput in an operating theatre), incremental change occurs when one compares different programs such as one view versus two view mammography. Incremental cost effectiveness refers to the difference in cost between the programs divided by the difference in outcome.
A description of two events, where knowing the outcome or value of one does not inform us about the outcome or value of the other. Formally, two events ‘A and B’ are independent if the probability that A and B occur together is equal to the probability of A occurring multiplied by the probability of B occurring.
When a variable is associated with an outcome after adjusting for multiple other potential prognostic factors (often after regression analysis), the association is an independent association.
An independent body (a review board or a committee, institutional, regional, national, or supranational), constituted of medical/scientific professionals and nonmedical/nonscientific members, whose responsibility it is to ensure the protection of the rights, safety, and well-being of human subjects involved in a trial and to provide public assurance of that protection, by, among other things, reviewing and approving/providing favorable opinion on the trial protocol, the suitability of the investigator(s), facilities, and the methods and material to be used in obtaining and documenting informed consent of the trial subjects.
An exposure, risk factor, or other characteristic that is hypothesized to influence the dependent variable. In a clinical trial, the outcome (over which the investigator has no direct control) is the dependent variable, and the treatment arm is the independent variable. In an adjusted analysis, patient characteristics are included as additional independent variables. (Also called explanatory variable.)
An exposure, risk factor, or other characteristic being observed or measured that is hypothesized to influence an event or manifestation (the dependent variable).
A face-to-face conversation to explore issues; conducted without using a structured questionnaire.
An index is a system used to make finding information easier.
Indexes [MeSH - publication type]: works providing an analytical subject approach to materials in a field of knowledge.
The date of an important event that marks the beginning of monitoring patients for the occurrence of the outcome of interest.
The test whose diagnostic accuracy is being measured against the reference or gold standard.
In medicine, a sign, symptom, or medical condition that leads to the recommendation of a treatment, test, or procedure.
Identified and measured variables which help to show changes directly and indirectly relevant to goals, objectives and targets.
Indicators in the context of evaluation are simply one-dimensional measures that help to measure, to express, or at least to reflect and to simplify the more complex formulation of the objectives.
The impact of alternative patient management strategies on the productivity of the patient and others involved in the patient’s care.
Data that have not been put into a frequency distribution or rank ordered.
In meta-analysis: the availability of raw data for each study participant in each included study, as opposed to aggregate data (summary data for the comparison groups in each study). Reviews using individual patient data require collaboration of the investigators who conducted the original studies, who must provide the necessary data.
A meta-analysis in which individual patient data from each primary study are used to create pooled estimates. Such an approach can facilitate more accurate intention-to-treat analyses and informed subgroup analyses.
The termination of a clinical pregnancy, by deliberate interference that takes place before 20 completed weeks of gestational age (18 weeks post fertilization) or, if gestational age is unknown, of an embryo/fetus of less than 400 grams.
Intentional removal of a fetus from the uterus by any of a number of techniques.
Differences in access to health services for equal health needs and/or absence of enhanced access for socially, demographically, or geographically defined population groups with greater health needs.
The presence of systematic differences in one or more aspects of health across socially, demographically, or geographically defined population groups.
Inequalities in the receipt of health services for equal health needs and/or failure to receive increased or augmented services for socially, demographically, or geographically defined population groups with greater health needs.
The term is typically applied to children between the ages of 1 month and 12 months; however, definitions vary between birth and 3 years of age.
A child between 1 and 23 months of age.
Death in the first year of life.
Postnatal deaths from birth to 365 days after birth in a given population. Postneonatal mortality represents deaths between 28 days and 365 days after birth (as defined by National Center for Health Statistics). Neonatal mortality represents deaths from birth to 27 days after birth.
Probability of dying between birth and exactly one year of age expressed per 1000 live births.
Infant mortality rate is the probability of a child born in a specific year or period dying before reaching the age of one, if subject to age-specific mortality rates of that period. Infant mortality rate is strictly speaking not a rate (i.e. the number of deaths divided by the number of population at risk during a certain period of time) but a probability of death derived from a life table and expressed as rate per 1,000 live births.
The quotient between the number of deaths in children under 1 year of age in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The reported neonatal mortality rate is defined as the quotient between the number of children born alive that died before the age of 28 days in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The reported postneonatal mortality rate is defined as the quotient between the number of children that were alive after 27 days of age and died before the age of 1 year in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The estimated infant mortality rate is the quotient between the number of deaths in children under 1 year of age in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as estimated by the United Nations' Population Division.
The number of deaths of infants under age 1 per 1,000 live births in a given year.
Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infection.
Programs of disease surveillance, generally within health care facilities, designed to investigate, prevent, and control the spread of infections and their causative microorganisms.
A generalization made about a population from the study of a subset or sample of that population.
Absence of conception after 12 months of regular, unprotected intercourse (commonly used medical definition of infertility).
Inability to conceive within two years of exposure to pregnancy is the epidemiological definition recommended by the World Health Organization.
Infertility (demographic studies): inability of a non-contracepting sexually active woman to have a livebirth. Demographers have shifted the endpoint from conceptions to live births because it is difficult to collect complete data about conceptions in population-based studies. In addition, demographic analyses of infertility are often based on secondary data from demographic surveys that contain complete birth histories, but no information about induced abortions, miscarriages and stillbirths. It is common in demographic studies to use a period of exposure of five years.
Inability to reproduce after a specified period of unprotected intercourse. Reproductive sterility is permanent infertility.
The circulation or wide dispersal of information.
In qualitative research, the point in the analysis at which new data fail to generate new themes and new information. This is considered an appropriate stopping point for data collection in most methods and an appropriate stopping point for analysis in some methods.
An ethical requirement for participation in a research study, indicating that a competent person, in possession of all the relevant information, freely agrees to participate.
A process in which a person is given important facts about a medical procedure or treatment, a clinical trial, or genetic testing before deciding whether or not to participate. It also includes informing the patient when there is new information that may affect his or her decision to continue. Informed consent includes information about the possible risks, benefits, and limits of the procedure, treatment, trial, or genetic testing.
The process of learning the key facts about a clinical trial before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the trial explain the details of the study.
A process by which a subject voluntarily confirms his or her willingness to participate in a particular trial, after having been informed of all aspects of the trial that are relevant to the subject's decision to participate. Informed consent is documented by means of a written, signed, and dated informed consent form.
A process in which the risks, benefits, and expectations of an intervention or research project are disclosed to a patient or participant in order for the participant to make an informed decision concerning acceptance or participation. Requires competence, voluntariness (autonomy and lack of coercion), disclosure, comprehension of risks, burdens, and benefits, and consent. Required by regulation and provided for in protocols by those requesting participation or agreement, consent should be viewed, not simply as a form and signature, but as a process engaging the candidate and allowing for “autonomous authorization”. Children may give assent—that is, agree to participate—though they may lack capacity or comprehension for true informed consent. Communities may be asked to give consent for community based research through elected leadership, existing community networks, or ad hoc advisory groups. The question of who speaks for the community is still a subject of discussion.
Voluntary authorization, by a patient or research subject, with full comprehension of the risks involved, for diagnostic or investigative procedures, and for medical and surgical treatment.
A document that describes the rights of the study participants, and includes details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the trial at any time.
Documents describing a medical treatment or research project, including proposed procedures, risks, and alternatives, that are to be signed by an individual, or the individual's proxy, to indicate his/her understanding of the document and a willingness to undergo the treatment or to participate in the research.
Also called consent forms.
Information relating to the target population such as drug knowledge/use, socio-economic and demographic data can all be included to assess initial situation. Data sources, social perceptions and public discussion related to the situation can also be added.
A patient who is formally admitted (or “hospitalized”) to an institution for treatment and/or care and stays for a minimum of one night in the hospital or other institution providing inpatient care.
Persons admitted to health facilities which provide board and room, for the purpose of observation, care, diagnosis or treatment.
In-patient treatment is treatment in which the patient spends the night in the treatment center.
A quantified amount of a resource put in a process.
The act by a regulatory authority(ies) of conducting an official review of documents, facilities, records, and any other resources that are deemed by the authority(ies) to be related to the clinical trial and that may be located at the site of the trial, at the sponsor's and/or contract research organization’s (CROs) facilities, or at other establishments deemed appropriate by the regulatory authority(ies).
Any public or private entity or agency or medical or dental facility where clinical trials are conducted.
Any public or private entity or agency (including Federal, State, and other agencies).
The moral and ethical obligations or responsibilities of institutions.
A committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical trial is ethical and that the rights of study participants are protected. All clinical trials in the U.S. must be approved by an IRB before they begin.
Every institution that conducts or supports biomedical or behavioral research involving human participants must, by federal regulation, have an IRB that initially approves and periodically reviews the research in order to protect the rights of human participants.
A group of scientists, doctors, clergy, and consumers that reviews and approves the action plan for every clinical trial. There is an Institutional Review Board at every health care facility that does clinical research. Institutional Review Boards are designed to protect the people who take part in a clinical trial. Institutional Review Boards check to see that the trial is well designed, legal, ethical, does not involve unnecessary risks, and includes safeguards for patients. Also called IRB.
An independent body constituted of medical, scientific, and nonscientific members, whose responsibility it is to ensure the protection of the rights, safety, and well-being of human subjects involved in a trial by, among other things, reviewing, approving, and providing continuing review of trials, of protocols and amendments, and of the methods and material to be used in obtaining and documenting informed consent of the trial subjects.
Any board, committee, or other group formally designated by an institution to review biomedical research involving humans as subjects, to approve the initiation of and conduct periodic review of such research.
Hospital or other institutional committees established to protect the welfare of research subjects. Federal regulations (the "Common Rule" (45 CFR 46)) mandate the use of these committees to monitor federally-funded biomedical and behavioral research involving human subjects.
Also called research ethics committee.
Instruments refer to all the tools that are used to collect information on the target group, the evaluation, etc. The most widely used instruments in evaluation are self-report questionnaires. Other instruments include tests, ratings, interviews and observation instruments.
The principle that asserts that the effect of a treatment policy can be best assessed by evaluating on the basis of the intention to treat a subject (i.e. the planned treatment regimen) rather than the actual treatment given. It has the consequence that subjects allocated to a treatment group should be followed up, assessed and analyzed as members of that group irrespective of their compliance to the planned course of treatment.
Analysis of clinical trial results that includes all data from participants in the groups to which they were randomized even if they never received the treatment.
A strategy for analyzing data from a randomized controlled trial. All participants are included in the arm to which they were allocated, whether or not they received (or completed) the intervention given to that arm. Intention-to-treat analysis prevents bias caused by the loss of participants, which may disrupt the baseline equivalence established by randomization and which may reflect non-adherence to the protocol. The term is often misused in trial publications when some participants were excluded.
Strategy for the analysis of randomized controlled trials that compares patients in the groups to which they were originally randomly assigned.
The situation in which a treatment contrast (e.g. difference between investigational product and control) is dependent on another factor (e.g. centre). A quantitative interaction refers to the case where the magnitude of the contrast differs at the different levels of the factor, whereas for a qualitative interaction the direction of the contrast differs for at least one level of the factor.
The situation in which the effect of one independent variable on the outcome is affected by the value of a second independent variable. In a trial, a test of interaction examines whether the treatment effect varies across sub-groups of participants.
Programs that use participatory teaching and learning methods (i.e. group discussions, group exercises).
Any analysis intended to compare treatment arms with respect to efficacy or safety at any time prior to the formal completion of a trial.
Analysis comparing intervention groups at any time before the formal completion of a trial, usually before recruitment is complete. Often used with stopping rules so that a trial can be stopped if participants are being put at risk unnecessarily. Timing and frequency of interim analyses should be specified in the protocol.
A report of intermediate results and their evaluation based on analyses performed during the course of a trial.
An individual (or group of individuals) from within the organization being evaluated who is (are) responsible for collecting, analyzing and interpreting data.
The extent to which the design and conduct of a study are likely to have prevented bias. Variation in quality can explain variation in the results of studies included in a systematic review. More rigorously designed (better quality) trials are more likely to yield results that are closer to the truth. (Also called methodological quality but better thought of as relating to bias prevention.)
The index and comparison groups are selected and compared in such a manner that the observed differences between them on the dependent variables under study may, apart from sampling error, be attributed only to the hypothesized effect under investigation.
The extent to which observers rating or measuring a particular phenomenon agree with each other.
Mathematical process by which mortality-rate findings are applied to the entire population that the study is representative of, so as to obtain total numbers of deaths or percentages of the population that died over the recall period investigated.
The distance between the scores representing the 25th and 75th percentile ranks in a distribution.
The central portion of a distribution, calculated as the difference between the third quartile and the first quartile; this range includes about one-half of the observations in the set, leaving one-quarter of the observations on each side.
The property of yielding equivalent results when used by different raters on different occasions.
The degree of stability exhibited when a measurement is repeated under identical conditions by different raters. Reliability refers to the degree to which the results obtained by a measurement procedure can be replicated. Lack of inter-rater reliability may arise from divergences between observers or instability of the attribute being measured.
A research design that collects observations at multiple time points before and after an intervention (interruption). The design attempts to detect whether the intervention has had an effect significantly greater than the underlying trend.
Action in which the health sector and other relevant sectors of the economy collaborate, or interact to pursue health goals.
In medicine, a treatment or action taken to prevent or treat disease, or improve health in other ways.
The process of intervening on people, groups, entities or objects in an experimental study. In controlled trials, the word is sometimes used to describe the regimens in all comparison groups, including placebo and no-treatment arms.
An activity or set of activities aimed at modifying a process, course of action or sequence of events, in order to change one or several of their characteristics such as performance or expected outcome.
The group receiving the study agent that is being tested in a clinical trial or clinical study.
A group of participants in a study receiving a particular health care intervention. Parallel group trials include at least two intervention groups.
The generic name of the precise intervention being studied.
Instruments of examination, observation‚ or evaluation that were specifically constructed for an intervention.
Epidemiologic investigations designed to test a hypothesized cause-effect relation by modifying the supposed causal factor(s) in the study population.
In qualitative research, this is one of 3 basic data collection methods. It involves an interviewer asking questions to engage participants in dialogue to allow interpretation of experiences and events in the participants’ own terms. The 2 most common interviews are semistructured, detailed interviews of individuals or discussion-based interviews of several people, called focus groups. In quantitative research, a method of collecting data in which an interviewer obtains information from a participant through conversation.
In evaluation research, the interview is an instrument used to assess data on the implementation process and outcome. Interviews can differ in their degree of standardization (structured, semi-structured or unstructured interviews), the type of contact (face-to-face, telephone or written), or the number of people interviewed at the same time (individual or group interviews).
Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.
Interview [MeSH - publication type]: work consisting of a conversation with an individual regarding his or her background and other personal and professional details, opinions on specific subjects posed by the interviewer, etc.
Systematic error due to interviewer's subconscious or conscious gathering of selective data.
This is a measure of reproducibility that compares variance between patients to the total variance, including both between- and within-patient variance.
Within (the walls or boundaries of) a community or institution (e.g. a university). Used to distinguish from ‘external’ (extramural) sources of support (such as funding).
The property of yielding equivalent results when used by the same rater on different occasions.
The degree of stability exhibited when a measurement is repeated under identical conditions by the same rater. Reliability refers to the degree to which the results obtained by a measurement procedure can be replicated. Lack of intra-rater reliability may arise from divergences between instruments of measurement, or instability of the attribute being measured.
Prefactory summary to a special issue or section of a journal devoted to a specific topic. This introductory text can be of varying length and substance.
The most common kind of weight used to combine individual studies in a summary estimate. It can be applied to many effect sizes (relative risk, odds ratio, risk difference, proportions—like sensitivity or specificity—, etc.) and in observational studies when adjusted effect sizes (odds ratio, relative risk) are provided.
In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered investigational in other diseases or conditions. Also called experimental.
A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. A drug may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called experimental drug.
A pharmaceutical form of an active ingredient or placebo being tested or used as a reference in a clinical trial, including a product with a marketing authorization when used or assembled (formulated or packaged) in a way different from the approved form, or when used for an unapproved indication, or when used to gain further information about an approved use.
Drugs which have received FDA approval for human testing but have yet to be approved for commercial marketing. This includes drugs used for treatment while they still are undergoing clinical trials (Treatment IND). The main heading includes drugs under investigation in foreign countries.
A new drug, antibiotic drug, or biological drug that is used in a clinical investigation. It also includes a biological product used in vitro for diagnostic purposes.
An application that must be submitted to a regulatory agency (the FDA in the United States) before a drug can be studied in humans. This application includes results of previous experiments; how, where, and by whom the new studies will be conducted; the chemical structure of the compound; how it is thought to work in the body; any toxic effects found in animal studies; and how the compound is manufactured.
A researcher in a clinical trial or clinical study.
A person responsible for the conduct of the clinical trial at a trial site. If a trial is conducted by a team of individuals at a trial site, the investigator is the responsible leader of the team and may be called the principal investigator.
An individual who actually conducts a clinical investigation, i.e., under whose immediate direction the test article is administered or dispensed to, or used involving, a subject, or, in the event of an investigation conducted by a team of individuals, is the responsible leader of that team.
Investigator triangulation requires more than one investigator to collect and analyze the raw data, such that the findings emerge through consensus among a team of investigators.
A compilation of the clinical and nonclinical data on the investigational product(s) that is relevant to the study of the investigational product(s) in human subjects. Table of contents:
In bioethics, a prima facie principle implying equity or fairness, especially regarding the fair distribution in the population of benefits and risks of research, health care, or other goods. Contrasted with retributive justice operating in the criminal justice system.
A measure of the extent to which observers achieve agreement beyond the level expected to occur by chance alone. Kappa can take values from 0 (poor agreement) to 1.0 (perfect agreement).
Person with the particular background, knowledge, or special skills required to contribute information relevant to topics under examination in an evaluation.
A string of words attached to an article to be used to index or code the article in a database.
A scatter plot of the risk in the experimental group against the risk in the control group. Ideally the size of the plotting symbols should be proportional to the size of the trials. Trials in which the experimental treatment had a higher risk than the control will be in the upper left of the plot, between the y axis and the line of equality. If experimental is no better than control then the point will fall on the line of equality, and if the control treatment has a higher risk than the experimental treatment then the point will be in the lower right of the plot, between the x axis and the line of equality.
Laboratory manuals [MeSH - publication type]: works containing concise background information and directions for activities, including conducting experiments or diagnostic tests in the laboratory.
The systematic error introduced when the search of potential studies to be included in a meta-analysis is focused, in general, in one language (mainly English). Given that studies published in English are more widely read, it is possible that significant results of studies carried out in non-English countries are more published in English journals than in journals written in other languages.
A period of subclinical or inapparent pathologic changes following exposure, ending with the onset of symptoms of chronic disease.
Lay knowledge refers to the understanding that members of the lay public bring to an issue or problem.
The length of time between the detection of a disease (usually based on new, experimental criteria) and its usual clinical presentation and diagnosis (based on traditional criteria).
The bias that occurs when two tests for a disease are compared, and one test (the new, experimental one) diagnoses the disease earlier, but there is no effect on the outcome of the disease-- it may appear that the test prolonged survival, when in fact it only resulted in earlier diagnosis when compared to traditional methods. It is an important factor when evaluating the effectiveness of a specific test.
Oral presentation intended to present information or teach people about a particular subject, for example by a university or college teacher.
Speech read or delivered before an audience or class, especially for instruction or to set forth some subject.
Lectures [MeSH - publication type]: works consisting of speeches read or delivered before an audience or class, especially for instruction or to set forth some subject. They are differentiated from addresses [publication type] which are less didactic and more informational, entertaining, inspirational, or polemic.
Notes taken at the delivery or reading of a speech before an audience or class, usually given to instruct.
Lecture notes [MeSH - publication type]: works consisting of notes taken at the delivery or reading of a speech before an audience or class, usually given to instruct.
An individual or juridical or other body authorized under applicable law to consent, on behalf of a prospective subject, to the subject's participation in the clinical trial.
Legislation (or "statutory law") is law which has been promulgated (or "enacted") by a legislature or other governing body, or the process of making it.
The enactment of laws and ordinances and their regulation by official organs of a nation, state, or other legislative organization. It refers also to health-related laws and regulations in general or for which there is no specific heading.
Legislation [MeSH - publication type]: works consisting of the text of proposed or enacted legislation that may be in the form of bills, laws, statutes, ordinances, or government regulations.
A form of selection bias, a statistical distortion of results which can lead to incorrect conclusions about the data. Length time bias can occur when the lengths of intervals are analyzed by selecting intervals that occupy randomly chosen points in time or space. This process favors longer intervals, thus skewing the data. For example, length time bias can affect data on screening tests for cancer. Faster-growing tumors generally have a shorter asymptomatic phase than slower-growing tumors, and so are less likely to be detected. However, faster-growing tumors are also often associated with a poorer prognosis. Slower-growing tumors are hence likely to be over-represented in screening tests. This can mean screening tests are erroneously associated with improved survival, even if they have no actual effect on prognosis.
Letter [MeSH - publication type]: work consisting of written or printed communication between individuals or between persons and representatives of corporate bodies. the correspondence may be personal or professional. in medical and other scientific publications the letter is usually from one or more authors to the editor of the journal or book publishing the item being commented upon or discussed. letter is often accompanied by comment.
A ranking system used to describe the strength of the results measured in a clinical trial or research study. The design of the study (such as a case report for an individual patient or a randomized double-blinded controlled clinical trial) and the endpoints measured (such as survival or quality of life) affect the strength of the evidence.
Levels of evidence refer to a hierarchy of study designs that have been grouped according to their susceptibility to bias. The hierarchy indicates which studies should be given most weight in an evaluation where the same question has been examined using different types of study.
Life expectancy is the expected (in the statistical sense) number of years of life remaining at a given age.
The number of years of life that can be expected on average in a given population.
A figure representing the number of years, based on known statistics, to which any person of a given age may reasonably expect to live.
Average number of years that a newborn is expected to live if current mortality rates continue to apply. WHO computes life expectancy at birth from a period life table.
The average number of years that a newborn could expect to live, if he or she were to pass through life exposed to the sex- and age-specific death rates prevailing at the time of his or her birth, for a specific year, in a given country, territory, or geographic area.
Abilities for adaptive and positive behavior that enable individuals to deal effectively with the demands and challenges of everyday life.
Interventions that implement the concept of life skills. Life skills refers to a large group of psychosocial and interpersonal skills which can help people make informed decisions, communicate effectively, and develop coping and self-management skills that may help them lead a healthy and productive life. Life skills commonly include components that focus on social skills, personal skills and knowledge and also resistance skills. Life skills based interventions are often classified as part of the broader category of social influence based interventions.
The maximum age that human beings could reach under optimum conditions.
Typical way of life or manner of living characteristic of an individual or group.
In actuarial science, a life table (also called a mortality table or actuarial table) is a table which shows, for each age, what the probability is that a person of that age will die before their next birthday.
A tabular display of life expectancy and the probability of dying at each age (or age group) for a given population, according to the age-specific death rates prevailing at that time. The life table gives an organized, complete picture of a population's mortality.
A set of tabulations that describe the probability of dying, the death rate and the number of survivors for each age or age group. Accordingly, life expectancy at birth is an output of a life table.
Summarizing techniques used to describe the pattern of mortality and survival in populations. These methods can be applied to the study not only of death, but also of any defined endpoint such as the onset of disease or the occurrence of disease complications.
Functions constructed from a statistical model and a set of observed data which give the probability of that data for various values of the unknown model parameters. Those parameter values that maximize the probability are the maximum likelihood estimates of the parameters.
Ratio of the probability of a false negative result if the disease is present to the probability of a true negative result if the disease is absent.
Ratio of the probability of a true positive result if the disease is present to a false positive result if the disease is absent.
In evidence-based medicine, likelihood ratios are used for assessing the value of performing a diagnostic test. They use the sensitivity and specificity of the test to determine whether a test result usefully changes the probability that a condition (such as a disease state) exists.
A format for closed-response questions used to elicit attitudes of the respondents to a certain statement. The respondent chooses from among five categories: strongly agree, agree, undecided, disagree, strongly disagree.
Psychometric scale commonly used in questionnaires, and is the most widely used scale in survey research, such that the term is often used interchangeably with rating scale even though the two are not synonymous. When responding to a Likert questionnaire item, respondents specify their level of agreement to a statement.
In analytical chemistry, the detection limit, lower limit of detection, or LOD (limit of detection), is the lowest quantity of a substance that can be distinguished from the absence of that substance (a blank value) within a stated confidence limit (generally 1%).
Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
The term used for a regression analysis when the dependent or target variable is a continuous variable, and the relationship between the dependent and independent variables is thought to be linear.
A scale that increases in equal steps. In a linear scale on a RevMan forest plot, the distance between 0 and 5 is the same as the distance between 5 and 10, or between 10 and 15. A linear scale may be used when the range of numbers being represented is not large, or to represent differences.
Linkage and exchange strategies refer to initiatives that seek to promote research utilization in decision contexts, and encourage research that generates purposeful and useful evidence.
The proportion of the adult population aged 15 years and over which is literate, expressed as a percentage of the corresponding population, total or for a given sex, in a given country, territory, or geographic area, at a specific point in time, usually mid-year. For statistical purposes, a person is literate who can with understanding both read and write a short simple statement on his/her everyday life.
A literature review is a body of text that aims to review the critical points of current knowledge and or methodological approaches on a particular topic.
A summary and explanation of key studies relevant to a proposed project.
Published materials which provide an examination of recent or current literature. Review articles can cover a wide range of subject matter at various levels of completeness and comprehensiveness based on analyses of literature that may include research findings. The review may reflect the state of the art. It also includes reviews as a literary form.
Live birth in the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD 10) is defined as the complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of the pregnancy, which, after such separation, breathes or shows any other evidence of life such as heartbeat, umbilical cord pulsation, or definite movement of voluntary muscles, whether the umbilical cord has been cut or the placenta is attached.
The event that a fetus is born alive with heartbeats or respiration regardless of gestational age. Such liveborn is called a newborn infant (infant, newborn).
A strategy for changing clinician behavior. Inclusion of participating clinicians in discussions to create agreement with a suggested approach to change provider practice.
A strategy for changing clinician behavior. These persons are clinician peers who are recognized by their colleagues as model caregivers or who are viewed as having particular content expertise.
A scale in which the logarithm of a value is used instead of the value. In a logarithmic scale on a RevMan forest plot, the distance between 1 and 10 is the same as the distance between 10 and 100, or between 100 and 1000. A logarithmic scale may be used when the range of numbers being represented is large, or to represent ratios.
A logic model is a graphic representation of a program that describes the program’s essential components and expected accomplishments and conveys the logical relationship between these components and their outcomes.
The logic of evidence based practice identifies a cyclic relation between evaluation, evidence, practice, and further evaluation. It is based on the premise that evaluations determine whether anticipated intervention effects occur in practice, and identify unanticipated effects.
Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.
A form of regression analysis that models an individual's odds of disease or some other outcome as a function of a risk factor or intervention. It is widely used for dichotomous outcomes, in particular to carry out adjusted analysis.
The (natural) log of the odds ratio. It is used in statistical calculations and in graphical displays of odds ratios in systematic reviews.
Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.
An observational study design in which measurements are made over a period of time.
Studies in which variables relating to an individual or group of individuals are assessed over a period of time.
An observational study design in which the investigators follow subjects for future events.
Long-term care encompasses a broad range of help with daily activities that chronically disabled individuals need for a prolonged period of time.
Care over an extended period, usually for a chronic condition or disability, requiring periodic, intermittent, or continuous care.
Changes that occur as a result of many interventions. Long-term outcomes are likely to be changes in behavior, conditions (e.g. risk factors), and status (e.g. poverty rates).
The circumstance that occurs when researchers lose contact with some participants and thus cannot complete planned data collection efforts. A common cause of missing data, especially in long-term studies.
A sampling methodology using small sample sizes when conducting surveys in small geographical or population-based areas or lots.
Low birth weight is defined as a weight of less than 2,500 g (up to and including 2,499 g), irrespective of gestational age.
An infant having a birth weight of 2,500 gm. (5.5 lb.) or less but infant, very low birth weight is available for infants having a birth weight of 1,500 grams (3.3 lb.) or less.
The percentage of live births that weigh less than 2,500 g out of the total of live births during the same time period.
Percentage of liveborn infants that weigh less than 2,500 g, for a given time period.
The number of newborn children weighing less than 2,500 grams, as weighted at the time of birth or within the first hours of life, before significant postnatal weight loss has occurred, expressed per 100 live births, for a given year, in a given country, territory, or geographic area.
Magnitude refers to the size of the estimate of effect, and the statistical significance and/or importance(clinical or social) of a quantitative finding. Magnitude and statistical significance are numerical calculations, but judgments about the importance of a measured effect are relative to the topic and the decision context.
Failure of a professional person, a physician or lawyer, to render proper services through reprehensible ignorance or negligence or through criminal intent, especially when injury or loss follows.
The term managed care is used to describe a variety of techniques intended to reduce the cost of providing health benefits and improve the quality of care ("managed care techniques") for organizations that use those techniques or provide them as services to other organizations ("managed care organization or MCO"), or to describe systems of financing and delivering health care to enrollees organized around managed care techniques and concepts ("managed care delivery systems").
Health insurance plans intended to reduce unnecessary health care costs through a variety of mechanisms, including: economic incentives for physicians and patients to select less costly forms of care; programs for reviewing the medical necessity of specific services; increased beneficiary cost sharing; controls on inpatient admissions and lengths of stay; the establishment of cost-sharing incentives for outpatient surgery; selective contracting with health care providers; and the intensive management of high-cost health care cases. The programs may be provided in a variety of settings, such as health maintenance organizations and preferred provider organizations.
In publishing and academic contexts, a "manuscript" is the text submitted to the publisher or printer in preparation for publication, usually as a typescript prepared on a typewriter, or today, a printout from a PC, prepared in manuscript format.
Compositions written by hand, as one written before the invention or adoption of printing. A manuscript may also refer to a handwritten copy of an ancient author. A manuscript may be handwritten or typewritten as distinguished from a printed copy, especially the copy of a writer's work from which printed copies are made.
Manuscripts [MeSH - publication type]: works prepared by hand including handwritten or typescript drafts of pre-publication papers or works not otherwise reproduced in multiple copies.
Refers to the consequences of changes in the scale of service provision. The marginal cost/benefit is the change in cost/benefit arising from (strictly a one unit) increase or decrease in service provision. It does not mean small or insignificant and its meaning is best illustrated by contrasting it with the average. The marginal savings associated with a one day reduction in the length of a hospital stay for example are typically much lower than the average cost per hospital bed day because of the existence of fixed costs.
The additional cost associated with producing one more unit of output. As pointed out earlier, in considering the optimal level of service provision, it is this cost concept that is crucial in economics.
Number of live births to married women per 1,000 married women ages 15-44 or 15-49 in a given year.
A discrete random process with the property that the next state depends only on the current state.
A stochastic process such that the conditional probability distribution for a state at any future instant, given the present state, is unaffected by any additional knowledge of the past history of the system.
Markov models are tools used in decision analyses. Markov models are the basis of software programs that model what might happen to a cohort of patients during a series of cycles (e.g., periods of 1 year). The model allows for the possibility that patients might move from one health state to another. For instance, one patient may have a mild stroke in one 3-month cycle, continue with minimal functional limitation for a number of cycles, have a gastrointestinal bleeding episode in a subsequent cycle, and finally experience a major stroke. Ideally, data from randomized trials will determine the probability of moving from one state to another during any cycle under competing management options.
Marriage is a social union or legal contract between individuals that creates kinship.
The social institution involving legal and/or religious sanction whereby men and women are joined together for the purpose of founding a family unit.
Mass media denotes a section of the media specifically designed to reach a large audience. The term was coined in the 1920s with the advent of nationwide radio networks, mass-circulation newspapers and magazines. However, some forms of mass media such as books and manuscripts had already been in use for centuries.
Instruments or technological means of communication that reach large numbers of people with a common message: press, radio, television, etc.
Mass media reach all or a large part of the general population (broad coverage). They may be used to enhance public awareness on drugs, provide information on drugs or how to confront drug addiction. Examples are TV and cinema, advertising, press and radio (Internet, posters, leaflets, stickers, t-shirts, might be part of such a campaign).
Organized periodic procedures performed on large groups of people for the purpose of detecting disease.
A type of analysis in which subjects in a study group and a comparison group are made comparable with respect to extraneous factors by individually pairing study subjects with the comparison group subjects (e.g., age-matched controls).
A sampling method to ensure that the two groups to be compared have similar characteristics. In an intervention study, pairs of similar “matched” subjects are formed and then one member of the pair is randomly assigned to one group and the other member to the other group. In a case-control study: choosing one or more controls with particular matching attributes for each case. Researchers match cases and controls according to particular variables that are thought to be important, such as age and sex.
Facilities which administer the delivery of health care services to mothers and children.
Maternal death is the death of a woman while pregnant or within 42 days after termination of pregnancy, irrespective of the duration and site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. To facilitate the identification of maternal deaths in circumstances in which cause-of-death attribution is inadequate, ICD 10 introduced an additional category, pregnancy-related death, which is defined as the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the cause of death.
Also called maternal mortality.
Organized services to provide health care to expectant and nursing mothers.
Maternal deaths resulting from complications of pregnancy and childbirth in a given population.
Number of women dying of pregnancy-related causes out of 100,000 live births in a given year.
The maternal mortality ratio (MMR) is the annual number of female deaths from any cause related to or aggravated by pregnancy or its management (excluding accidental or incidental causes) during pregnancy and childbirth or within 42 days of termination of pregnancy, irrespective of the duration and site of the pregnancy, per 100,000 live births, for a specified year. Late maternal deaths are excluded from this calculation.
The number of women who die as a result of pregnancy and childbirth complications per 100,000 live births in a given year.
Number of maternal deaths per 100,000 live births during a specified time period, usually 1 year.
The quotient between the number of maternal deaths in a given year and the number of live births in that same year, expressed by 100,000 live births, for a given country, territory, or geographic area, as reported from the national health authority. Maternal death is defined as the death of a woman while pregnant or within the 42 days after termination of that pregnancy, regardless of the length and site of the pregnancy, due to any cause related to or aggravated by the pregnancy itself or its care but not due to accidental or incidental causes.
The highest dose of a drug or treatment that does not cause unacceptable side effects. The maximum tolerated dose is determined in clinical trials by testing increasing doses on different groups of people until the highest dose with acceptable side effects is found. Also called MTD.
The highest dose of a biologically active agent given during a chronic study that will not reduce longevity from effects other than carcinogenicity.
In mathematics and statistics, the arithmetic mean (or simply the mean) of a list of numbers is the sum of all of the list divided by the number of items in the list.
The mathematical average age of all the members of a population.
In meta-analysis: a method used to combine measures on continuous scales (such as weight), where the mean, standard deviation and sample size in each group are known. The weight given to the difference in means from each study (e.g. how much influence each study has on the overall results of the meta-analysis) is determined by the precision of its estimate of effect and, in the statistical software in RevMan and the Cochrane Database of Systematic Reviews, is equal to the inverse of the variance. This method assumes that all of the trials have measured the outcome on the same scale.
A quantified relationship between exposure and disease; includes relative risk, rate ratio, odds ratio.
A central value that best represents a distribution of data. Measures of central location include the mean, median, and mode. Also called the measure of central tendency.
A measure of the spread of a distribution out from its central value. Measures of dispersion used in epidemiology include the interquartile range, variance, and the standard deviation.
Measurement bias occurs when the methods of measurement are consistently dissimilar in different groups of patients.
Also called information bias.
Measurement validity refers to the degree to which a measurement actually measures what it purports to.
The median of a distribution is a midpoint at which one half of the observations fall below and one half fall above the value.
The age that divides a population into two numerically equal groups; that is, half the people are younger than this age and half are older.
Length of time that one-half of the study population survives.
A medical algorithm is any computation, formula, statistical survey, nomogram, or look-up table, useful in healthcare. Medical algorithms include decision tree approaches to healthcare treatment (i.e., if symptoms A, B, and C are evident, then use treatment X) and also less clear-cut tools aimed at reducing or defining uncertainty. Medical algorithms are part of a broader field which is usually fit under the aims of medical informatics and medical decision making. Medical decisions occur in several areas of medical activity including medical test selection, diagnosis, therapy and prognosis, and automatic control of medical equipment.
A detailed review and evaluation of selected clinical records by qualified professional personnel for evaluating quality of medical care.
Medical classification, or medical coding, is the process of transforming descriptions of medical diagnoses and procedures into universal medical code numbers.
Medical consensus is a public statement on a particular aspect of medical knowledge available at the time it was written, and that is generally agreed upon as the evidence-based, state-of-the-art (or state-of-science) knowledge by a representative group of experts in that area.
Economic aspects of the field of medicine, the medical profession, and health care. It includes the economic and financial impact of disease in general on the patient, the physician, society, or government.
Medical error is an inaccurate or incomplete diagnosis and/or treatment of a disease; injury; syndrome; behavior; infection or other ailment.
Errors or mistakes committed by health professionals which result in harm to the patient. They include errors in diagnosis (diagnostic errors), errors in the administration of drugs and other medications (medication errors), errors in the performance of surgical procedures, in the use of other types of therapy, in the use of equipment, and in the interpretation of laboratory findings. Medical errors are differentiated from malpractice in that the former are regarded as honest mistakes or accidents while the latter is the result of negligence, reprehensible ignorance, or criminal intent.
Medical ethics is primarily a field of applied ethics, the study of moral values and judgments as they apply to medicine.
The principles of professional conduct concerning the rights and duties of the physician, relations with patients and fellow practitioners, as well as actions of the physician in patient care and interpersonal relations with patient families.
A medical guideline (also called a clinical guideline, clinical protocol or clinical practice guideline) is a document with the aim of guiding decisions and criteria regarding diagnosis, management, and treatment in specific areas of healthcare.
The field of information science concerned with the analysis and dissemination of medical data through the application of computers to various aspects of health care and medicine.
A medical journal is a scientific journal devoted to the field of medicine.
Medical law is the branch of law which concerns the prerogatives and responsibilities of medical professionals and the rights of the patient.
Medical literature refers to articles in journals and texts in books devoted to the field of medicine.
Medical malpractice is professional negligence by act or omission by a health care provider in which care provided deviates from accepted standards of practice in the medical community and causes injury or death to the patient.
A medical practice or practice of medicine is the practice of medicine, as performed by a medical practitioner—a physician (medical doctor). Typically, practicing medicine involves giving a diagnosis and prescribing a treatment for medical condition.
A medical record, health record, or medical chart is a systematic documentation of a patient's individual medical history and care.
Recording of pertinent information concerning patient's illness or illnesses.
Medical statistics deals with applications of statistics to medicine and the health sciences, including epidemiology, public health, forensic medicine, and clinical research.
Reproduction brought about through ovulation induction, controlled ovarian stimulation, ovulation triggering, ART procedures, and intrauterine, intracervical, and intravaginal insemination with semen of husband/partner or donor.
A legal drug that is used to prevent, treat, or relieve symptoms of a disease or abnormal condition.
Voluntary cooperation of the patient in taking drugs or medicine as prescribed. This includes timing, dosage, and frequency.
Also called medication compliance.
Error in prescribing, dispensing, or administering medication with the result that the patient fails to receive the correct drug or the indicated proper drug dosage.
Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions. This term may also refer to a legal drug used for the same purpose.
The art and science of studying, performing research on, preventing, diagnosing, and treating disease, as well as the maintenance of health.
Meeting abstracts [MeSH - publication type]: for individual abstracts of presentations at meetings, congresses, conferences, symposia, colloquia, seminars, workshops, round tables, and other professional gatherings.
In qualitative research, this involves sharing draft study findings with the participants to inquire whether their viewpoints were faithfully interpreted and to ascertain whether the account makes sense to participants with different perspectives.
In epidemiology, Mendelian randomization is a method of using non-experimental studies to examine the causal effect of a modifiable exposure on disease by making use of measured variation in genes of known function.
The use of the genetic variation of known functions or phenotypes to correlate the causal effects of those functions or phenotypes with a disease outcome.
The use of statistical techniques in a systematic review to integrate the results of included studies. Sometimes misused as a synonym for systematic reviews, where the review includes a meta-analysis.
A statistical technique that summarizes the results of several studies in a single weighted estimate, in which more weight is given to results of studies with more events and sometimes to studies of higher quality.
A quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine.
Meta-analysis [MeSH - publication type]: works consisting of studies using a quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc. It is often an overview of clinical trials. It is usually called a meta-analysis by the author or sponsoring body and should be differentiated from reviews of literature.
In meta-analysis: a technique used to explore the relationship between study characteristics (e.g. concealment of allocation, baseline risk, timing of the intervention) and study results (the magnitude of effect observed in each study) in a systematic review.
A collection of statistical procedures (weighted/unweighted linear, logistic regression) to assess heterogeneity, in which the effect size of study is regressed on one or several covariates, with a value defined for each study.
A procedure for combining qualitative research on a specific topic in which researchers compare and analyze the texts of individual studies and develop new interpretations.
Methodological rigor refers to the robustness and credibility of the methods that are used in a study, and whether the study methods are appropriate to the study question.
The precise design of a study, including the methods used.
The halfway point or midpoint in a set of observations. For most types of data, it is calculated as the sum of the smallest observation and the largest observation, divided by two. For age data, one is added to the numerator. The midrange is usually calculated as an intermediate step in determining other measures.
In statistics, the mid-range or mid-extreme of a set of statistical data values is the arithmetic mean of the maximum and minimum values in a data set.
A midwife is a person who, having been regularly admitted to a midwifery educational program that is duly recognized in the country in which it is located, has successfully completed the prescribed course of studies in midwifery and has acquired the requisite qualifications to be registered and/or legally licensed to practice midwifery. The educational program may be an apprenticeship, a formal university program, or a combination.
WHO Statistical Information System: includes professional midwives, auxiliary midwives and enrolled midwives. Traditional birth attendants are counted as community health workers.
A health care profession in which providers offer care to childbearing women during their pregnancy, labor and birth, and during the postpartum period. They also care for the newborn through to six weeks of age, including assisting the mother with breastfeeding.
The practice of assisting women in childbirth.
The Millennium Development Goals (MDGs) are eight international development goals that all 192 United Nations member states and at least 23 international organizations have agreed to achieve by the year 2015. They include reducing extreme poverty, reducing child mortality rates, fighting disease epidemics such as AIDS, and developing a global partnership for development.
The smallest difference in a patient-important outcome that patients perceive as beneficial and that would mandate, in the absence of troublesome adverse effects and excessive cost, a change in the patient’s health care management.
A method of allocation used to provide comparison groups that are closely similar for several variables. The next participant is assessed with regard to several characteristics, and assigned to the treatment group that has so far had fewer such people assigned to it. It can be done with a component of randomization, where the chance of allocation to the group with fewer similar participants is less than one. Minimization is best performed centrally with the aid of a computer program to ensure concealment of allocation.
The term minor is used to refer to a person who is under the age in which one legally assumes adulthood and is legally granted rights afforded to adults in society. Depending on the jurisdiction and application, this age may vary, but is usually marked at either 12, 16, 18, 20, or 21. Specifically, the status of minor is defined by the age of majority.
A person who has not attained the age at which full civil rights are accorded.
The concept covering the physical and mental conditions of members of minority groups.
The spontaneous loss of a clinical pregnancy that occurs before 20 completed weeks of gestational age (18 weeks post fertilization) or, if gestational age is unknown, the loss of an embryo/fetus of less than 400 grams.
The spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving, generally defined in humans at prior to 20 weeks of gestation.
Expulsion of the product of fertilization before completing the term of gestation and without deliberate interference.
Also called spontaneous abortion.
A clinical abortion where the embryo(s) or fetus(es) is/are non-viable and is/are not expelled spontaneously from the uterus.
The retention in the uterus of a dead fetus two months or more after its death.
A study that combines data collection approaches, sometimes both qualitative and quantitative, into the study methodology and is commonly used in the study of service delivery and organization. Some mixed-methods studies combine study designs (e.g., investigators may embed qualitative or quantitative process evaluations alongside quantitative evaluative designs to increase understanding of factors influencing a phenomenon). Some mixed-methods studies include a single overarching research design but use mixed-methods for data collection (e.g., surveys, interviews, observation, and analysis of documentary material).
The most frequent measurement in a distribution.
A measure of central location, the most frequently occurring value in a set of observations.
Molecular epidemiology is a branch of medical science that focuses on the contribution of potential genetic and environmental risk factors, identified at the molecular level, to the etiology, distribution and prevention of disease within families and across populations.
The application of molecular biology to the answering of epidemiological questions. The examination of patterns of changes in DNA to implicate particular carcinogens and the use of molecular markers to predict which individuals are at highest risk for a disease are common examples.
The continuous oversight of an activity to assist in its supervision and to see that it proceeds according to plan.
The act of overseeing the progress of a clinical trial, and of ensuring that it is conducted, recorded, and reported in accordance with the protocol, standard operating procedures (SOPs), GCP, and the applicable regulatory requirement(s).
A written report from the monitor to the sponsor after each site visit and/or other trial-related communication according to the sponsor's SOPs.
A monograph is a work of writing upon a single subject, usually also by a single author.
Monograph [MeSH - publication type]: work that is any publication that is not a serial or integrating resource. in cataloging usage, it is usually on a single subject or related subjects and is complete in itself, whether constructed of chapters, sections, or parts. While any article encountered in indexing journals can be, strictly speaking, a monograph, as a publication type, a monograph will refer to a cataloging item.
Monte Carlo methods (or Monte Carlo experiments) are a class of computational algorithms that rely on repeated random sampling to compute their results.
In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo.
The possibility of consumers or providers exploiting a benefit system unduly to the detriment or disadvantage of other consumers, providers or the financing community as a whole, without having to bear the financial consequences or their behavior in part or in full.
Duties that are based in ethics, rather than in law.
Morbidity (from Latin morbidus: sick, unhealthy) refers to a diseased state, disability, or poor health due to any cause. The term may be used to refer to the existence of any form of disease, or to the degree that the health condition affects the patient.
The frequency of disease, illness, injuries, and disabilities in a population.
The proportion of patients with a particular disease during a given year per given unit of population.
In epidemiology and actuarial science, the term morbidity rate can refer to either the incidence rate, or the prevalence of a disease or medical condition.
Morbidity rate refers to the number of individuals in poor health during a given time period (the prevalence rate) or the number who currently have that disease (the incidence rate), scaled to the size of the population.
Illness or disability rate, usually expressed per 1000 population.
All deaths reported in a given population.
Mortality rate is a measure of the number of deaths (in general, or due to a specific cause) in some population, scaled to the size of that population, per unit time. Mortality rate is typically expressed in units of deaths per 1000 individuals per year; thus, a mortality rate of 9.5 in a population of 100,000 would mean 950 deaths per year in that entire population.
Death rate per defined population, usually expressed per 1000.
A measure of the benefit of a treatment in terms of lives saved. The mortality reduction can be represented in many ways, including relative risk reduction, absolute risk reduction, and increased life expectancy.
A trial with more than two arms.
A clinical trial that is carried out at more than one medical institution.
A clinical trial conducted according to a single protocol but at more than one site, and, therefore, carried out by more than one investigator.
A trial conducted at several geographical sites. Trials are sometimes conducted among several collaborating institutions, rather than at a single institution - particularly when very large numbers of participants are needed.
Controlled studies which are planned and carried out by several cooperating institutions to assess certain variables and outcomes in specific patient populations, for example, a multicenter study of congenital anomalies in children.
Multicenter study [MeSH - publication type]: work consisting of a controlled study executed by several cooperating institutions.
A treatment planning approach in which a number of doctors who are experts in different specialties (disciplines) review and discuss the medical condition and treatment options of a patient.
In statistics, hierarchical linear modeling (HLM), also known as multi-level analysis, is a more advanced form of simple linear regression and multiple linear regression.
The statistical manipulation of hierarchically and non-hierarchically nested data. It includes clustered data, such as a sample of subjects within a group of schools. Prevalent in the social, behavioral sciences, and biomedical sciences, both linear and nonlinear regression models are applied.
The simultaneous use of multiple laboratory procedures for the detection of various diseases. These are usually performed on groups of people.
The performance of multiple analyses on the same data. Multiple statistical comparisons increase the probability of making a Type I error, i.e. attributing a difference to an intervention when chance is a reasonable explanation.
A type of regression that provides a mathematical model that explains or predicts the dependent or target variable by simultaneously considering all of the independent or predictor variables.
A statistical model in which the combined effect of several factors is the product of the effects produced by each in the absence of the others. For example, if one factor multiplies risk by a% and a second factor by b%, the combined effect of the two factors is a multiplication by (a x b)%.
A multiple birth occurs when more than one fetus is carried to term in a single pregnancy.
Multiple gestation/birth: a pregnancy/delivery with more than one fetus/neonate.
The offspring in multiple pregnancies (pregnancy, multiple): twins; triplets; quadruplets; quintuplets; etc.
The condition of bearing two or more fetuses simultaneously.
The proliferation of possible comparisons in a trial. Common sources of multiplicity are multiple outcome measures, outcomes assessed at several time points after the intervention, and subgroup analyses. Also arises when there are multiple intervention groups.
A multistage sample is an extension of a cluster sample, where the initial clusters are broken into further smaller clusters. Once a final selection of clusters to sample is made, a proportion of the subjects within each cluster is sampled. (e.g. if the sampling frame was an entire country then the country would be broken down into regions, then these regions would be broken down into cities and towns and then these would be randomly sampled).
Measuring the impact of more than one variable at a time while analyzing a set of data, e.g. looking at the impact of age, sex, and occupation on a particular outcome. Performed using regression analysis.
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables. Table of contents:
A randomized trial in an individual to determine the optimum treatment for that individual. The individual is given repeated administrations of experimental and control interventions (or of two or more experimental treatments), with the order of the treatments being randomized.
The act, process, or an instance of narrating, i.e., telling a story. In the context of medicine or ethics, narration includes relating the particular and the personal in the life story of an individual.
Verbal answers that take the form of a story or explanation, or which describe a series of events.
A review article (e.g., a typical book chapter) that is not conducted using methods to minimize bias (in contrast to a systematic review).
Narrative review is sometimes used to describe a non-systematic review.
Systematic review of heterogeneous studies, where it is more appropriate to describe the range of available evidence than to combine the findings into an overall result. A narrative systematic review can be conducted on both quantitative and qualitative research.
Births as a component of population change.
Components of a national health care system which administer specific services, e.g., national health insurance.
As distinct from prognosis, natural history refers to the possible consequences and outcomes of a disease or condition and the frequency with which they can be expected to occur when the disease condition is untreated.
A former branch of knowledge embracing the study, description, and classification of natural objects (as animals, plants, and minerals) and thus including the modern sciences of zoology, botany, and mineralogy insofar as they existed at that time. In the 17th, 18th, and 19th centuries it was much used for the generalized pursuit of certain areas of science.
The temporal course of disease from onset (inception) to resolution.
A study that follows a group of people over time who have, or are at risk of developing, a specific medical condition or disease. A natural history study collects health information in order to understand how the medical condition or disease develops and how to treat it.
Study of the natural development of something (such as an organism or a disease) over a period of time.
A causal factor whose presence is required for the occurrence of the effect (of disease).
A systematic procedure for determining the nature and extent of health needs in a population, the causes and contributing factors to those needs and the human, organizational and community resources which are available to respond to these.
Needs assessment (or needs analysis) is the systematic appraisal of a perceived phenomenon as well as the appropriateness of the proposed intervention.
Systematic identification of a population's needs or the assessment of individuals to determine the proper level of services needed.
A negative correlation between two variables implies that as one variable gets bigger the value of the other variable becomes smaller.
As clinical studies accumulate, it is more common for effects to shrink than to increase. Negative effects are smaller or less dramatic than effects from previous studies.
The ratio of the probability that an individual with the target condition has a negative test result to the probability that an individual without the target condition has a negative test result. This is the same as the ratio (1-sensitivity/specificity).
In screening/diagnostic tests: a measure of the usefulness of a screening/diagnostic test. It is the proportion of those with a negative test result who do not have the disease, and can be interpreted as the probability that a negative test result is correct. It is calculated as follows: NPV = Number with a negative test who do not have disease/Number with a negative test.
A term often used to refer to a study with results that either do not indicate a beneficial effect of treatment or that have not reached statistical significance. The term can generate confusion because it can refer to either statistical significance or the direction of effect. Studies often have multiple outcomes, the criteria for classifying studies as ‘negative’ are not always clear and, in the case of studies of risk or undesirable effects, ‘negative’ studies are ones that do not show a harmful effect.
Continuous care and monitoring of newborn infants with life-threatening conditions, in any setting.
A neonatal intensive care unit, usually shortened NICU and also called a newborn intensive care unit, intensive care nursery (ICN), and special care baby unit (SCBU), or a humidicrib, is a unit of a hospital specializing in the care of ill or premature newborn infants.
Hospital units providing continuing surveillance and care to acutely ill newborn infants.
Death of a liveborn infant within the first 28 days.
Number of deaths during the first 28 completed days of life per 1,000 live births in a given year or other period. Neonatal deaths (deaths among live births during the first 28 completed days of life) may be subdivided into early neonatal deaths, occurring during the first 7 days of life, and late neonatal deaths, occurring after the 7th day but before the 28th completed day of life.
The number of deaths to infants under 28 days of age in a given year per 1,000 live births in that year.
The neonatal period commences at birth and ends 28 completed days after birth.
The identification of selected parameters in newborn infants by various tests, examinations, or other procedures. Screening may be performed by clinical or laboratory measures. A screening test is designed to sort out healthy neonates from those not well, but the screening test is not intended as a diagnostic device, rather instead as epidemiologic.
Enrolment of the official age group for primary level education expressed as a percentage of the corresponding population.
The average number of daughters that would be born to a woman (or a group of women) if she passed through her lifetime conforming to the age-specific fertility and mortality rates of a given year. This rate is similar to the gross reproduction rate but takes into account that some women will die before completing their childbearing years. An NRR of one means that each generation of mothers is having exactly enough daughters to replace itself in the population. See also total fertility rate and replacement-level fertility.
The application of nonlinear statistics to pattern-recognition problems. Neural networks can be used to develop clinical prediction rules. The technique identifies those predictors most strongly associated with the outcome of interest that belong in a clinical prediction rule and those that can be omitted from the rule without loss of predictive power.
An application submitted by the manufacturer of a drug to the FDA - after clinical trials have been completed - for a license to market the drug for a specified indication.
News [MeSH - publication type]: works consisting of an announcement or statement of recent or current events of new data and matters of interest in the field of medicine or science. In some publications, such as "Nature" or "Science," the news reports are substantively written and herald medical and scientific data of vital or controversial importance.
Data in which the categories cannot be ordered one above another. Examples of categorical nominal variables are sex and marital status.
Classification into unordered qualitative categories; e.g., race, religion, and country of birth as measurements of individual attributes are purely nominal scales, as there is no inherent order to their categories.
A variable that can be classified into a category (e.g., male or female sex); often called categorical variable. A categorical variable may be nominal or ordinal. Categorical variables can be defined according to attributes without any associated order (e.g., medical admission, elective surgery, or emergency surgery); these are called nominal variables. A categorical variable can also be defined according to attributes that are ordered (e.g., height such as high, medium, or low); these are called ordinal variables.
Graphic scale facilitating calculation of a probability. The most-used nomogram in the evidence-based medicine world is one developed by Fagan to move from a pretest probability, through a likelihood ratio, to a posttest probability.
Graphical representation of a statistical model containing scales for calculating the prognostic weight of a value for each individual variable. Nomograms are instruments that can be used to predict outcomes using specific clinical parameters. They use algorithms that incorporate several variables to calculate the predicted probability that a patient will achieve a particular clinical endpoint.
Patients are nonadherent if they are not exposed to the full course of a study intervention (e.g., most commonly, they do not take the prescribed dose or duration of a drug or they do not participate fully in the study program).
Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group. If human subjects are involved, they know what treatments they are receiving.
Biomedical studies not performed on human subjects.
A clinical study that includes some, but not all, of the eligible patients identified by the researchers during the study registration period. This type of study does not usually have a control group.
A trial with the primary objective of showing that the response to the investigational product is not clinically inferior to a comparative agent (active or placebo control).
A trial designed to determine whether the effect of a new treatment is not worse than a standard treatment by more than a pre-specified amount. A one-sided version of an equivalence trial.
Programs that use didactic methods (i.e. lecturers, presentation of films).
An ethical principle implying that where research involves experimentation on human subjects, the subjects should suffer no harm.
Literally, not causing harm. A prima facie principle in bioethics, sometimes subsumed under the principle of beneficence. An obligation traditionally at the heart of medical ethics—the “first do no harm” component of the Hippocratic Oath—non-maleficence can be seen as distinct from the obligation to produce good.
Information linked to the person by a code (not including personal identification) known to the investigator.
A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data.
A non probability sample is one in which individuals are selected for a survey on the basis of some shared characteristic. For example, all the students in the same classroom, or all the patients attending a diabetes clinic. These examples, also known as convenience samples, introduce a bias into the measurement of the outcome of interest. For example, patients who attend a diabetes clinic may either already know or suspect that they suffer from the disease. Thus, the prevalence of diabetes in this sample is likely to be very high, and not representative of the prevalence of diabetes in the community.
A clinical trial in which the participants are not assigned by chance to different treatment groups. Participants may choose which group they want to be in, or they may be assigned to the groups by the researchers.
Any quantitative study estimating the effectiveness of an intervention (harm or benefit) that does not use randomization to allocate units to comparison groups (including studies where ‘allocation’ occurs in the course of usual treatment decisions or peoples’ choices, i.e. studies usually called ‘observational’). To avoid ambiguity, the term should be substantiated using a description of the type of question being addressed. For example, a 'non-randomized intervention study' is typically a comparative study of an experimental intervention against some control intervention (or no intervention) that is not a randomized controlled trial. There are many possible types of non-randomized intervention study, including cohort studies, case-control studies, controlled before-and-after studies, interrupted-time-series studies and controlled trials that do not use appropriate randomization strategies (sometimes called quasi-randomized studies).
A non-marital and non-cohabiting partner.
A review or meta-analysis that either did not perform a comprehensive search of the literature and contains only a selection of studies on a clinical question, or did not state its methods for searching and appraising the studies it contains.
Human experimentation that is not intended to benefit the subjects on whom it is performed. Phase I drug studies (clinical trials, phase I) and research involving healthy volunteers are examples of nontherapeutic human experimentation.
The highest dosage administered that does not produce toxic effects. The NOAEL will depend on how closely dosages are spaced (lowest-observed-adverse-effect level and no-observed-effect level) and the number of animals examined. The ultimate objective is usually to determine not the "safe" dosage in laboratory animals but the "safe" dosage for humans. Therefore, the extrapolation most often required of toxicologists is from high-dosage studies in laboratory animals to low doses in humans.
A bell-shaped curve that results when a normal distribution is graphed.
A statistical distribution with known properties commonly used as the basis of models to analyze continuous data. Key assumptions in such analyses are that the data are symmetrically distributed about a mean value, and the shape of the distribution can be described using the mean and standard deviation.
The symmetrical clustering of values around a central location. The properties of a normal distribution include the following: (1) It is a continuous, symmetrical distribution; both tails extend to infinity; (2) the arithmetic mean, mode, and median are identical; and, (3) its shape is completely determined by the mean and standard deviation.
Continuous frequency distribution of infinite range. Its properties are as follows: 1, continuous, symmetrical distribution with both tails extending to infinity; 2, arithmetic mean, mode, and median identical; and 3, shape completely determined by the mean and standard deviation.
Also called Gaussian distribution.
A bell-shaped curve of the frequency distribution of the data.
In Clinical Evidence, not significant means that the observed difference, or a larger difference, could have arisen by chance with a probability of more than 1/20 (i.e. 5%), assuming that there is no underlying difference. This is not the same as saying there is no effect, just that this experiment does not provide convincing evidence of an effect. This could be because the trial was not powered to detect an effect that does exist, because there was no effect, or because of the play of chance. If there is a potentially clinically important difference that is not statistically significant then do not say there was a non-significant trend. Alternative phrases to describe this type of uncertainty include, "Fewer people died after taking treatment x but the difference was not significant" or "The difference was not significant but the confidence intervals covered the possibility of a large beneficial effect" or even, "The difference did not quite reach significance."
The statistical hypothesis that one variable (e.g. which treatment a study participant was allocated to receive) has no association with another variable or set of variables (e.g. whether or not a study participant died), or that two or more population distributions do not differ from one another. In simplest terms, the null hypothesis states that the factor of interest (e.g. treatment) has no impact on outcome (e.g. risk of death).
The first step in testing for statistical significance in which it is assumed that the exposure is not related to disease.
A nonsignificant result; no statistically significant difference between groups.
A woman who has never been pregnant.
A woman who has never given birth to a child.
An epidemiological measure that indicates how many patients need to be exposed to a risk-factor over a specific period to cause harm in one patient that would not otherwise have been harmed. It is defined as the inverse of the attributable risk. Intuitively, the lower the number needed to harm, the worse the risk-factor.
A number needed to treat to benefit associated with a harmful effect. It is an estimate of how many people need to receive a treatment before one more person would experience a harmful outcome or one fewer person would experience a beneficial outcome.
The number of patients who would need to be screened to prevent one adverse event.
The number needed to treat (NNT) is an epidemiological measure used in assessing the effectiveness of a health-care intervention, typically a treatment with medication. The NNT is the number of patients who need to be treated in order to prevent one additional bad outcome (i.e. the number of patients that need to be treated for one to benefit compared with a control in a clinical trial). It is defined as the inverse of the absolute risk reduction.
The number of patients who need to be treated over a specific period of time to achieve one additional good outcome. When discussing NNT, it is important to specify the intervention, its duration, and the desirable outcome. It is the inverse of the absolute risk reduction (ARR), expressed as a percentage (100/ARR).
Absolute measures are useful at describing the effort required to obtain a benefit, but are limited because they are influenced by both the treatment and also by the baseline risk of the individual. If a meta-analysis includes individuals with a range of baseline risks, then no single NNT will be applicable to the people in that meta-analysis, but a single relative measure (odds ratio or relative risk) may be applicable if there is no heterogeneity. In Clinical Evidence, an NNT is provided for meta-analysis, based on a combination of the summary odds ratio (OR) and the mean baseline risk observed in average of the control groups.
Total number of community health workers in the country.
A measure of the efficacy of a treatment or habit in terms of increase or decrease in life expectancy.
Total number of environment and public health workers in the country.
The number of deaths in children under 1 year of age in a given year, for a given country, territory, or geographic area, expressed as number of deaths, as reported from the national health authority.
The number of maternal deaths in a given year and the number of live births in that same year for a given country, territory, or geographic area, as reported from the national health authority. Maternal death is defined as the death of a woman while pregnant or within the 42 days after termination of that pregnancy, regardless of the length and site of the pregnancy, due to any cause related to or aggravated by the pregnancy itself or its care, but not due to accidental or incidental causes.
Total number of nursing and midwifery personnel in the country.
Total number of other health service providers in the country (excepting physicians, nursing and midwifery personnel, dentistry personnel and community health workers).
The number of outpatient health care facilities, affiliated to all health institutions, in operation during a given year, for a given country, territory, or geographic area. Outpatient health care is defined as any professional encounter or contact, as an act of health service, between a non-hospitalized individual and a health worker responsible for the evaluation, diagnosis, treatment, or referral of that person in that encounter. Outpatient health care facility is defined as any type of physical area primarily designated to deliver outpatient health care services. Institutional affiliation includes any outpatient health care facility managed by the Ministry of Health or by a governmental equivalent, by Social Security systems, including those for the Army and Police Forces, and by private, for-profit or non-profit, voluntary-driven or not, organizations.
Total number of medical doctors (physicians) in the country.
Data expressed in numbers.
The frequency, characteristics, and dissolution of marriages in a population.
A nurse is a healthcare professional who, in collaboration with other members of a health care team, is responsible for: treatment, safety, and recovery of acutely or chronically ill individuals; health promotion and maintenance within families, communities and populations; and, treatment of life-threatening emergencies in a wide range of health care settings. Nurses perform a wide range of clinical and non-clinical functions necessary to the delivery of health care, and may also be involved in medical and nursing research.
WHO Statistical Information System: includes professional nurses, auxiliary nurses, enrolled nurses and other nurses, such as dental nurses and primary care nurses.
Professionals qualified by education at an accredited school of nursing and licensed by state law to practice nursing. They provide services to patients requiring assistance in recovering or maintaining their physical or mental health.
Research concerned with establishing costs of nursing care, examining the relationships between nursing services and quality patient care, and viewing problems of nursing service delivery within the broader context of policy analysis and delivery of health services.
A detailed review and evaluation of selected clinical records by qualified professional personnel for evaluating quality of nursing care.
Care given to patients by nursing service personnel.
Investigations into the problems of integrating research findings into nursing curricula, developing problem solving skills, finding approaches to clinical teaching, determining the level of practice by graduates from different basic preparations, etc.
A branch of applied ethics that concerns itself with activities in the field of nursing. Nursing ethics shares many principles with medical ethics, such as beneficence, non-maleficence and respect for autonomy. It can be distinguished by its emphasis on relationships, maintaining dignity and collaborative care. The principles of proper professional conduct concerning the rights and duties of nurses themselves, their patients, and their fellow practitioners, as well as their actions in the care of patients and in relations with their families.
Research carried out by nurses that uses interviews, data collection, observation, surveys, etc., to evaluate nursing, health, clinical, and nursing education programs and curricula, and which also demonstrates the value of such evaluation.
Research carried out by nurses concerning techniques and methods to implement projects and to document information, including methods of interviewing patients, collecting data, and forming inferences. The concept includes exploration of methodological issues such as human subjectivity and human experience.
The term used to describe the evidence used to support nursing practice.
Research carried out by nurses, generally in clinical settings, in the areas of clinical practice, evaluation, nursing education, nursing administration, and methodology. Table of contents:
An improvement that can be measured by the health care provider.
A measurable response.
The general questions the trial was designed to answer. May be associated with one or more hypotheses that, when tested, will help answer the question.
Objectives are specific and measurable statements regarding the desired outcome of a prevention intervention. For evaluation purposes, the formulation of objectives must specify the variables to be changed and establish measurable success criteria. A plausible, testable assumption must link program activities to objectives, and objectives to intended outcomes. If the objectives are vague, it will not be possible to implement an intervention or assess the effectiveness of the intervention.
Objective measures are made in a process involving a minimum amount of human interpretation, for example measurement of height.
Objectivity is, along with reliability and validity, an important indicator for the quality of an instrument. It refers to the fact that the results yielded by the instrument must be independent of the person measuring the data - different people using the same instrument should come to the same results.
Used interchangeably with duty. That which is required, although tempered by competing duties. Obligations are correlated with rights. In epidemiology and public health, professional role obligations derive from basic ethical principles and are articulated in codes of professional conduct.
Closely monitoring a patient's condition but withholding treatment until symptoms appear or change. Also called watchful waiting, active surveillance, and expectant management.
The act of regarding attentively and studying facts and occurrences, gathering data through analyzing, measuring, and drawing conclusions, with the purpose of applying the observed information to theoretical assumptions. Observation as a scientific method in the acquisition of knowledge began in classical antiquity; in modern science and medicine its greatest application is facilitated by modern technology. Observation is one of the components of the research process.
A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).
A study in which the investigators do not seek to intervene, and simply observe the course of events. Changes or differences in one characteristic (e.g. whether or not people received the intervention of interest) are studied in relation to changes or differences in other characteristic(s) (e.g. whether or not they died), without action by the investigator. There is a greater risk of selection bias than in experimental studies.
Epidemiological study in situations where nature is allowed to take its course. Changes or differences in one characteristic are studied in relation to changes or differences in others, without the intervention of the investigator.
Occurs when an observer’s observations differ systematically according to participant characteristics (e.g., making systematically different observations in treatment and control groups).
The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).
Also called observer variation.
The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).
Delivery of the fetus and placenta under the care of an obstetrician or a health worker. Obstetric deliveries may involve physical, psychological, medical, or surgical interventions.
The repetitive uterine contraction during childbirth which is associated with the progressive dilation of the uterine cervix (cervix uteri). Successful labor results in the expulsion of the fetus and placenta. Obstetric labor can be spontaneous or induced (labor, induced).
The percentage of a hospital’s beds filled at a specific time (or in a specific period).
The promotion and maintenance of physical and mental health in the work environment.
A way of expressing the chance of an event, calculated by dividing the number of individuals in a sample who experienced the event by the number for whom it did not occur. For example, if in a sample of 100, 20 people died and 80 people survived the odds of death are 20/80 = ¼, 0.25 or 1:4.
The ratio of the odds of an event in one group to the odds of an event in another group. In studies of treatment effect, the odds in the treatment group are usually divided by the odds in the control group. An odds ratio of one indicates no difference between comparison groups. For undesirable outcomes an OR that is less than one indicates that the intervention was effective in reducing the risk of that outcome. When the risk is small, odds ratios are very similar to risk ratios. (Also called OR.)
An odds of an event is the number of events divided by the number of non-events. In epidemiology an event might be a disease studied in the exposed group versus the control group, e.g. lung cancer. An odds ratio is obtained by dividing the odds in the exposed group by the control group.
The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.
The odds reduction expresses, for odds, what relative risk reduction expresses for risks. Just as the relative risk reduction is 1 – relative risk, the odds reduction is 1 – relative odds (the relative odds and odds ratio being synonymous). Thus, if a treatment results in an odds ratio of 0.6 for a particular outcome, the treatment reduces the odds for that outcome by 0.4.
Describes the legal use of a prescription drug to treat a disease or condition for which the drug has not been approved by the U.S. Food and Drug Administration.
A drug prescribed for conditions other than those approved by the FDA.
The practice of prescribing or using a drug outside the scope of the drug's official approved label as designated by a regulatory agency concerning the treatment of a particular disease or condition.
Refers to the provision of evidence in a readily available form, providing accurate information and facilitating timeliness.
A statistical test where a difference between two groups, if true, is expected to be in one direction. For example, the difference between passive smokers and non-smokers in the occurrence of lung cancer is expected to be in one direction. It is not expected that smoking will protect from lung cancer, and so there is no need to test for it. A one-tailed test will need a smaller sample size than a two-tailed test.
A clinical trial in which the investigator and participant are aware which intervention is being used for which participant (i.e. not blinded). Random allocation may or may not be used in such trials. Sometimes called an ‘open label’ design.
A clinical trial in which the investigator decides which intervention is to be used (non-random allocation). This is sometimes called an open label design (but some trials which are said to be ‘open label’, are randomized).
A clinical trial that uses an open sequential design.
A question asked without providing a pre-defined set of responses to select from.
A type of study in which both the health providers and the patients are aware of the drug or treatment being given.
A clinical trial in which doctors and participants know which drug or vaccine is being administered.
A sequential trial where the decision to stop the trial rests on the size of effect in those studies, and there is no finite maximum number of participants in the study.
These are technical, intermediate aims in order to achieve the changes in the target group previously defined as specific objective. Operational objectives are the outputs or products of the intervention, for instance training sessions held, manuals published and distributed, teachers trained, schools involved, peers recruited, but also the demands for repetition of the intervention and the degree of acceptance.
Operations research, also known as operational research, is an interdisciplinary branch of applied mathematics and formal science that uses advanced analytical methods such as mathematical modeling, statistical analysis, and mathematical optimization to arrive at optimal or near-optimal solutions to complex decision-making problems. It is often concerned with determining the maximum (of profit, performance, or yield) or minimum (of loss, risk, or cost) of some real-world objective.
A group of techniques developed to apply scientific methods and tools to solve the problems of decision making in complex organizations and systems. Operations research searches for optimal solutions in situations of conflicting goals and makes use of mathematical models from which solutions for actual problems may be derived.
Opportunities are health benefits that are part of neither the original intentions nor proposals but that provide a chance to improve health and wellbeing by adjusting the design or adding new project components.
The value of (health or other) benefits forgone in alternative uses when a resource is used.
The value of a resource in its most favored alternative use. Because of scarcity, choices among competing claims on the limited resources must be made. As the example of allocative efficiency shows, the opportunity cost of additional investment in preventing childhood accidents could be the potential health gains forgone by children with asthma. It follows that an economic evaluation is a method of comparing the benefits of alternative allocations of resources.
Categorical data in which the variables can be ordered one above another. An example of ordinal categorical data is the number of children a woman has.
Data that are classified into more than two categories which have a natural order; for example, non-smokers, ex-smokers, light smokers and heavy smokers. Ordinal data are often reduced to two categories to simplify analysis and presentation, which may result in a considerable loss of information.
Classification into ordered qualitative categories; e.g., social class (I, II, III, etc.), where the values have a distinct order, but their categories are qualitative in that there is no natural (numerical) distance between their positive values.
Descriptions and evaluations of specific health care organizations.
An FDA category that refers to medications used to treat diseases and conditions that occur rarely. There is little financial incentive for the pharmaceutical industry to develop medications for these diseases or conditions. Orphan drug status, however, gives a manufacturer specific financial incentives to develop and provide such medications.
Drugs or biologicals which are unlikely to be manufactured by private industry unless special incentives are provided by others.
WHO Statistical Information System: includes a large number of occupations such as dieticians and nutritionists, medical assistants, occupational therapists, operators of medical and dentistry equipment, optometrists and opticians, physiotherapists, podiatrists, prosthetic/orthetic engineers, psychologists, respiratory therapists, speech pathologists, medical trainees and interns.
Outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected in a particular time and place.
Sudden increase in the incidence of a disease. The concept includes epidemics and pandemics.
Also called disease outbreak.
A change to a situation resulting from an action.
A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.
A component of a participant's clinical and functional status after an intervention has been applied, that is used to assess the effectiveness of an intervention.
Evaluation procedures that focus on both the outcome or status (outcomes assessment) of the patient at the end of an episode of care - presence of symptoms, level of activity, and mortality; and the process (assessment, process) - what is done for the patient diagnostically and therapeutically.
Research aimed at assessing the quality and effectiveness of health care as measured by the attainment of a specified end result or outcome. Measures include parameters such as improved health, lowered morbidity or mortality, and improvement of abnormal states (such as elevated blood pressure).
Systematic process of collecting, analyzing and interpreting data to assess and evaluate what outcomes an intervention has achieved. In other words, outcome evaluation measures how clients and their circumstances change and whether the intervention experience has been a factor in causing this change.
Outcome evaluation refers to the consequent effect of a program on the health outcomes in populations, corresponding to the program goal or target.
Outcome evaluation monitors indicators and health outcomes after the proposal has been implemented.
Outcome indicators relate the results of a project in the target group to its specific objectives (and the underlying working hypothesis).
The target variable of interest. The variable that is hypothesized to depend on or be caused by another variable, the independent variable.
Those aspects of health that result from the interventions provided by the health system, the facilities and personnel that recommend them and the actions of those who are the targets of the interventions.
Evaluates the impact of health care on the health outcomes of patients and populations.
A list of the main features of a given topic, often used as a rough draft or summary of the content of a document.
Outlines [MeSH - publication type]: works consisting of brief statements of the principal elements of a subject, usually arranged by heads and subheads.
A patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.
Persons who receive ambulatory care at an outpatient department or clinic without room and board being provided.
The number of outpatient health care visits per every 1,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area.
The result of a process.
The immediate result of implementing surveillance and response activities.
Community-based activities with the aim of getting in touch with persons who are not effectively reached by existing services. One key element is active contact-making with high-risk groups in a setting where they are comfortable, and keeping in close contact with them, instead of waiting for these people to approach services. Activities range from prevention to healthcare and advice for untreated drug users.
Overall [MeSH - publication type]: a single citation covering several articles of various degrees of specificity or a single citation covering papers or abstracts presented at a meeting. A subject overall refers to a series of articles on a single subject; a congress overall refers to papers presented at a formal local, regional, national, or international gathering; a society overall refers to papers presented at an annual, semi-annual, monthly, weekly, or other meeting of a society, academy, institute, hospital, etc.
The main purpose of the intervention- the solution or modification of the stated problem. Its definition should include a brief description of the expected change, preferably a quantifiable measure of outcomes, with regard to population and when it is expected to be achieved.
A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen. Also called nonprescription drug and OTC.
Medicines that can be sold legally without a drug prescription.
A type of review in which primary research relevant to a question is examined and summarized, and an effort is made to identify all available literature (published or unpublished) that pertains to that question. Table of contents:
The probability (ranging from zero to one) that the results observed in a study (or results more extreme) could have occurred by chance if in reality the null hypothesis was true. In a meta-analysis, the P-value for the overall effect assesses the overall statistical significance of the difference between the intervention groups, whilst the P-value for the heterogeneity statistic assesses the statistical significance of differences between the effects observed in each study.
A study in which participants or groups of participants are matched (e.g. based on prognostic factors). One member of each pair is then allocated to the experimental (intervention) group and the other to the control group.
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance a continent, or even worldwide.
An epidemic occurring over a very wide area (several countries or continents) and usually affecting a large proportion of the population.
A trial that compares two groups of people concurrently, one of which receives the intervention of interest and one of which is a control group. Some parallel trials have more than two comparison groups and some compare different interventions without including a non-intervention control group. (Also called independent group design.)
A quantity defining a theoretical model. Unlike variables, parameters do not relate to actual measurements or attributes of patients.
Statistical tests that can be applied when the data fall in a normal distribution, that is, when they are spread evenly around the mean, and the frequency distribution curve is bell-shaped or Gaussian.
Parental consent laws (also known as parental involvement or parental notification laws) in some countries require that one or more parents consent to or be notified before their minor child can legally engage in certain activities.
Reporting to parents or guardians about care to be provided to a minor.
The number of children previously born alive to a woman; for example, 'two-parity women' are women who have had two children and 'zero-parity women' have had no live births.
Number of births for a given woman, counting a multiple birth pregnancy as one. In some demographic studies, stillbirths do not count toward parity.
The number of offspring a female has borne. It is contrasted with gravidity, which refers to the number of pregnancies, regardless of outcome.
Occurs when only a selected sample of patients who underwent the index test is verified by the reference standard, and that sample is dependent on the results of the test. For example, patients with suspected coronary artery disease whose exercise test results are positive may be more likely to undergo coronary angiography (the reference standard) than those whose exercise test results are negative.
An individual who is studied in a trial, often but not necessarily a patient.
Research, with the collaboration of those affected by the issue being studied (includes individuals and organizations), for the purpose of taking action or effecting change.
A voluntary contract between two or more doctors who may or may not share responsibility for the care of patients, with proportional sharing of profits and losses.
The proportion of persons infected, after exposure to a causative agent, who then develop clinical disease.
A person in contact with the health system seeking attention for a health condition.
Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.
The seeking and acceptance by patients of health service.
Also called healthcare patient acceptance.
A person who helps a patient work with others who have an effect on the patient's health, including doctors, insurance companies, employers, case managers, and lawyers. A patient advocate helps resolve issues about health care, medical bills, and job discrimination related to a patient's medical condition.
Promotion and protection of the rights of patients, frequently through a legal process.
The services rendered by members of the health profession and non-professionals under their supervision for the benefit of the patient.
Generating, planning, organizing, and administering medical and nursing care and services for patients.
Design of patient care wherein institutional resources and personnel are organized around patients rather than around specialized departments.
Patient education handout [MeSH - publication type]: works consisting of a handout or self-contained informative material used to explain a procedure or a condition or the contents of a specific article in a biomedical journal and written in non-technical language for the patient or consumer.
The probability of the occurrence of the endpoint or outcome of interest in the patient group of which the individual under consideration is representative.
Laws requiring patients under managed care programs to receive services from the physician or other provider of their choice. Any willing provider laws take many different forms, but they typically prohibit managed-care organizations from having a closed panel of physicians, hospitals, or other providers.
Outcomes that patients value directly. This is in contrast to surrogate, substitute, or physiologic outcomes that clinicians may consider important. One way of thinking about a patient-important outcome is that, were it to be the only thing that changed, patients would be willing to undergo a treatment with associated risk, cost, or inconvenience. This would be true of treatments that ameliorated symptoms or prevented morbidity or mortality. It would not be true of treatments that lowered blood pressure, improved cardiac output, improved bone density, or the like, without improving the quality or increasing the length of life.
A strategy for changing clinician behavior. Any intervention aimed at changing the performance of health care professionals through interactions with, or information provided by or to, patients.
Patient participation, also called shared decision making, is patient involvement in the decision-making process in matters pertaining to health.
Patient involvement in the decision-making process in matters pertaining to health.
The relative value that patients place on various health states. Preferences are determined by values, beliefs, and attitudes that patients bring to bear in considering what they will gain or lose as a result of a management decision. Explicit enumeration and balancing of benefits and risks that is central to evidence-based clinical practice brings the underlying value judgments involved in making management decisions into bold relief.
Individual's expression of desirability or value of one course of action, outcome, or selection in contrast to others.
A patient-reported outcome or PRO is a questionnaire used in a clinical trial or a clinical setting, where the responses are collected directly from the patient.
Fundamental claims of patients, as expressed in statutes, declarations, or generally accepted moral principles. The term is used for discussions of patient rights as a group of many rights, as in a hospital's posting of a list of patient rights.
Healthcare discipline that emphasizes the reporting, analysis, and prevention of medical error that often lead to adverse healthcare events.
The degree to which the individual regards the health care service or product or the manner in which it is delivered by the provider as useful, effective, or beneficial.
Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.
Review of a clinical trial by experts chosen by the study sponsor. These experts review the trials for scientific merit, participant safety, and ethical considerations.
A refereeing process for checking the quality and importance of reports of research. An article submitted for publication in a peer-reviewed journal is reviewed by other experts in the area.
An organized procedure carried out by a select committee of professionals in evaluating the performance of other professionals in meeting the standards of their specialty. Review by peers is used by editors in the evaluation of articles and other papers submitted for publication. Peer review is used also in the evaluation of grant applications. It is applied also in evaluating the quality of health care provided to patients.
A journal in which the articles are vetted by independent referees for quality and interest, and is therefore more highly regarded.
Per capita general government expenditure on health (GGHE) expressed in PPP international dollar.
Per capita general government expenditure on health (GGHE) expressed at average exchange rate for that year in US dollar. Current prices.
Per capita total expenditure on health (THE) expressed in PPP international dollar.
Per capita total expenditure on health (THE) expressed at average exchange rate for that year in US$. Current prices.
An analysis of the subset of participants from a randomized controlled trial who complied with the protocol sufficiently to ensure that their data would be likely to exhibit the effect of treatment. This subset may be defined after considering exposure to treatment, availability of measurements and absence of major protocol violations. The per protocol analysis strategy may be subject to bias as the reasons for non-compliance may be related to treatment.
The set of data generated by the subset of subjects who complied with the protocol sufficiently to ensure that these data would be likely to exhibit the effects of treatment, according to the underlying scientific model. Compliance covers such considerations as exposure to treatment, availability of measurements and absence of major protocol violations.
A percentile (or centile) is the value of a variable below which a certain percent of observations fall.
The set of numbers from 0 to 100 that divide a distribution into 100 parts of equal area, or divide a set of ranked data into 100 class intervals with each interval containing 1/100 of the observations. A particular percentile, say the 5th percentile, is a cut point with 5 percent of the observations below it and the remaining 95% of the observations above it.
Systematic differences between intervention groups in care provided apart from the intervention being evaluated. For example, if participants know they are in the control group, they may be more likely to use other forms of care. If care providers are aware of the group a particular participant is in, they might act differently. Blinding of study participants (both the recipients and providers of care) is used to protect against performance bias.
Concerns how interventions are performed without regard to whether they should be performed. An example would be the acceptable range of results reported for reference cholesterol samples sent to clinical laboratories.
The care of a fetus or newborn given before, during, and after delivery from the 28th week of gestation through the 7th day after delivery.
Fetal or neonatal death occurring during late pregnancy (at 20 completed weeks of gestational age and later), during childbirth and up to 7 completed days after birth.
Fetal deaths beginning at 22 completed weeks (154 days) plus deaths of live births within the first seven days after birth. Live births eligible to be considered as perinatal deaths must be at least 500 g, or 22 completed weeks of gestation, or 25 cm in body length to be included in many national perinatal statistics. For international perinatal mortality statistics, live births must have been either 1,000 g or 28 completed weeks gestation or 35 cm in body length.
Deaths occurring from the 28th week of gestation to the 7th day after birth.
The number of fetal deaths after 28 weeks of pregnancy (late fetal deaths) plus the number of deaths to infants under 7 days of age per 1,000 live births.
The ICD-10 defines “perinatal” as the time period starting at 22 completed weeks (154 days) gestation and lasting through seven days after birth
The branch of medicine dealing with the fetus and infant during the perinatal period. The perinatal period begins with the twenty-eighth week of gestation and ends twenty-eight days after birth.
Observation of a population at a specific period of time. Such an analysis in effect takes a 'snapshot' of a population in a relatively short time period — for example, one year. Most rates are derived from period data and therefore are period rates.
In a cross-over trial: a difference in the measured outcomes from one treatment period to another. This could be caused, for instance, by all patients in a trial naturally healing over time.
In epidemiology, period prevalence is the proportion of the population with a given disease or condition over a specific period of time.
An approach to generating an allocation sequence in which the number of assignments to intervention groups satisfies a specified allocation ratio (such as 1:1 or 2:1) after every "block" of specified size. For example, a block of size 12 would contain 6 A and 6 B with a ratio of 1:1 or 8 A and 4 B with a ratio of 2:1. Generating the allocation sequence involves randomly selecting from all the permutations of assignments that meet the specified ratio.
Cumulative time spent by each individual at risk in the population. Used in the formal expression of mortality rates, and necessary when comparing mortality rates in periods that are different in length for each individual in the population (e.g. before versus after arrival to a camp).
A measure of the incidence rate of an event, e.g., a disease or death, in a population at risk over an observed period to time, that directly incorporates time into the denominator.
The average number of years that each participant is followed up for, multiplied by the number of participants.
Personal narratives [MeSH - publication type]; works consisting of accounts of personal experience in relation to a particular field or of participation in related activities or autobiographical accounts.
The state or condition of being a human individual accorded moral and/or legal rights. Criteria to be used to determine this status are subject to debate, and range from the requirement of simply being a human organism to such requirements as that the individual be self-aware and capable of rational thought and moral agency.
A way of combining odds ratios that has become widely used in meta-analysis. It is especially used to analyze trials with time to event outcomes. The calculations are straightforward and understandable, but this method produces biased results in some circumstances. It is a fixed-effect model.
A statistical method to combine individual studies, derived from the Mantel-Haenszel's procedure, in which the observed outcomes in the index group are compared with the expected ones, and weighting by its variance.18 It should only be used when the sample size of the arms of a study are balanced and the effect size is close to the null value.
The study of the use and effects of drugs in large groups of people.
The science concerned with the benefit and risk of drugs used in populations and the analysis of the outcomes of drug therapies. Pharmacoepidemiologic data come from both clinical trials and epidemiological studies with emphasis on methods for the detection and evaluation of drug-related adverse effects, assessment of risk vs benefit ratios in drug therapy, patterns of drug utilization, the cost-effectiveness of specific drugs, methodology of postmarketing surveillance, and the relation between pharmacoepidemiology and the formulation and interpretation of regulatory guidelines.
The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine.
Dynamic and kinetic mechanisms of exogenous chemical and drug absorption; biological transport; tissue distribution; biotransformation; elimination; and toxicology as a function of dosage, and rate of metabolism. it includes toxicokinetics, the pharmacokinetic mechanism of the toxic effects of a substance. ADME and ADMET are short-hand abbreviations for absorption, distribution, metabolism, elimination and toxicology.
A book containing directions for the identification of samples and the preparation of compound medicines, and published by the authority of a government or a medical or pharmaceutical society.
Authoritative treatises on drugs and preparations, their description, formulation, analytic composition, physical constants, main chemical properties used in identification, standards for strength, purity, and dosage, chemical tests for determining identity and purity, etc. They are usually published under governmental jurisdiction (e.g., USP, the United States Pharmacopoeia; BP, British Pharmacopoeia; P. Helv., the Swiss Pharmacopoeia). They differ from formularies in that they are far more complete: formularies tend to be mere listings of formulas and prescriptions.
Pharmacopoeias [MeSH - publication type]: authoritative works containing lists of drugs and preparations, their description, formulation, analytic composition, main chemical properties, standards for strength, purity, and dosage, chemical tests for determining identity, etc. They have the status of a standard.
First trials of a new active ingredient or new formulation in humans, often carried out in healthy volunteers.
Studies performed to evaluate the safety of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques in healthy subjects and to determine the safe dosage range (if appropriate). These tests also are used to determine pharmacologic and pharmacokinetic properties (toxicity, metabolism, absorption, elimination, and preferred route of administration). They involve a small number of persons and usually last about 1 year. This concept includes phase I studies conducted both in the U.S. and in other countries.
Clinical trial, phase I [MeSH - publication type]: work that is the report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on a small number of healthy persons and conducted over the period of about a year in either the United States or a foreign country.
Trials performed in a limited number of subjects and often of a comparative (e.g. placebo-controlled) design, to demonstrate therapeutic activity and to assess the short-term safety of the active ingredient in patients suffering from a disease or condition for which the active ingredient is intended.
Studies that are usually controlled to assess the effectiveness and dosage (if appropriate) of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques. These studies are performed on several hundred volunteers, including a limited number of patients with the target disease or disorder, and last about two years. This concept includes phase II studies conducted in both the U.S. and in other countries.
Clinical trial, phase II [MeSH - publication type]: work that is a report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques based on several hundred volunteers, including a limited number of patients, and conducted over a period of about two years in either the United States or a foreign country.
Trials including larger (and possibly varied) patient groups, with the purpose of determining the short-and long-term safety/efficacy balance of formulation(s) of the active ingredient, and of assessing its overall and relative therapeutic value.
Comparative studies to verify the effectiveness of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques determined in phase II studies. During these trials, patients are monitored closely by physicians to identify any adverse reactions from long-term use. These studies are performed on groups of patients large enough to identify clinically significant responses and usually last about three years. This concept includes phase III studies conducted in both the U.S. and in other countries.
Clinical trial, phase III [MeSH - publication type]: work that is a report of a pre-planned, usually controlled, clinical study of the safety and efficacy of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques after phase II trials. A large enough group of patients is studied and closely monitored by physicians for adverse response to long-term exposure, over a period of about three years in either the United States or a foreign country.
Studies performed after marketing of the pharmaceutical product to discover rare and remote side-effects.
Planned post-marketing studies of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale. These studies are often conducted to obtain additional data about the safety and efficacy of a product. This concept includes phase IV studies conducted in both the U.S. and in other countries.
Clinical trial, phase IV [MeSH - publication type]: work that is a report of a planned post-marketing study of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale after clinical trials, phases I, II, and III. These studies, conducted in the United States or a foreign country, often garner additional data about the safety and efficacy of a product.
A person who has completed studies in medicine at the university level. To be legally licensed for the independent practice of medicine, (s)he must, in most cases, undergo additional postgraduate training in a hospital.
Individuals licensed to practice medicine.
The number of physicians available per every 10,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area.
A graphical method of representing the frequency distribution of a set of categorical data in the shape of a pie.
A circular chart in which the size of each "slice is proportional to the frequency of each category of a variable.
The initial study examining a new method or treatment.
A preliminary study to test the feasibility of the protocol, before implementing the study proper. It may also be called “pre-test”.
A smaller version or trial run of a larger study that is conducted in preparation for that study; can involve pre-testing or ‘trying out’ a research tool such as a data-collecting form.
Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.
A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness.
An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
An inactive substance or procedure administered to a participant, usually to compare its effects with those of a real drug or other intervention, but sometimes for the psychological benefit to the participant through a belief that s/he is receiving treatment. Placebos are used in clinical trials to blind people to their treatment allocation. Placebos should be indistinguishable from the active intervention to ensure adequate blinding.
Any dummy medication or treatment. Although placebos originally were medicinal preparations having no specific pharmacological activity against a targeted condition, the concept has been extended to include treatments or procedures, especially those administered to control groups in clinical trials in order to provide baseline measurements for the experimental protocol.
A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.
Refers to a clinical study in which the control patients receive a placebo.
A physical or emotional change, occurring after a substance is taken or administered, that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the participant and, often, the expectations of the person giving the substance.
The phenomenon where, in an intervention study, subjects receiving, without knowing, an inert drug, show an improvement or perception of improvement in their condition, probably due to their expectations.
An effect usually, but not necessarily, beneficial that is attributable to an expectation that the regimen will have an effect, i.e., the effect is due to the power of suggestion.
An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial. Also called sham therapy.
The wrongful appropriation, close imitation, or purloining and publication, of another author's language, thoughts, ideas, or expressions, and the representation of them as one's own original work.
Passing off as one's own the work of another without credit.
Statistical analyses specified in the trial protocol; that is, planned in advance of data collection. In contrast to unplanned analyses. (Also called a priori analyses, pre-specified analyses.)
The results (e.g. mean, weighted mean difference, odds ratio, risk ratio or risk difference) obtained in a sample (a study or a meta-analysis) which are used as the best estimate of what is true for the relevant population from which the sample is taken.
Most likely value for the parameter of interest (e.g. crude mortality rate) obtained through a sample survey. A point estimate should always be accompanied by a confidence interval.
In epidemiology, point prevalence is a measure of the proportion of people in a population who have a disease or condition at a particular time, such as a particular date.
The amount of a particular disease present in a population at a single point in time.
A statistical distribution with known properties used as the basis of analyzing the number of occurrences of relatively rare events occurring over time.
A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a continuum of time or space.
A set of statements or commitments to pursue courses of action aimed at achieving defined goals of public or private institutions.
A policy is a course or principle of action adopted or proposed by an organization or individual.
A policy represents the way in which government or an organization seeks to achieve the objectives it has set.
A person with power to influence or determine policies and practices at an international, national, regional or local level. Policy-makers have the responsibility and commitment for making the appropriate use of the best available evidence for policy-making and decision-taking. The policy-maker is someone who sets the plan pursued by a government or organization, a person whose actions and opinions strongly influence the course of events.
The decision process by which individuals, groups or institutions establish policies pertaining to plans, programs or procedures.
This is a relevant question (gap) concerning policies and/or strategic issues or directions in a specific context (governments, organizations, etc.) that has to be addressed by a policy-maker (decision-maker) and affects the ‘real’ world by guiding the decisions that are made. These policy questions may be formally written or not. Most organizations identify their gaps (policy questions) and define policies to solve them.
A type of health provider that provides ambulatory health care for more than one specialty of services.
Estimate based on combining data from 2 or more samples.
The estimation of a summary (or pooled) effect size after the statistical aggregation of the individual studies.
An entire set of persons, animals, objects or events which the researcher intends to study.
All the inhabitants of a country, territory, or geographic area, total or for a given sex and/or age group, at a specific point of time. In demographic terms it is the total number of inhabitants of a given sex and/or age group that actually live within the border limits of the country, territory, or geographic area at a specific point of time, usually mid-year. The mid-year population refers to the actual population at July 1st.
The total number of individuals inhabiting a particular region or area.
A survey where the sample is representative of the population being studied.
Qualities and characterization of various types of populations within a social or geographic group, with emphasis on demography, health status, and socioeconomic factors.
A broad concept that addresses the relationship between fertility, mortality, and migration, but is most commonly used to refer to efforts to slow population growth through action to lower fertility. It should not be confused with family planning.
Human population control is the practice of artificially altering the rate of growth of a human population.
Includes mechanisms or programs which control the numbers of individuals in a population of humans or animals.
Population per unit of land area; for example, people per square mile or people per square kilometer of arable land.
Number of individuals in a population relative to space.
The patterns of settlement and dispersal of a population.
The branch of life sciences that studies short- and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes.
The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.
The study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow.
The discipline studying genetic composition of populations and effects of factors such as genetic selection, population size, mutation, migration, and genetic drift on the frequencies of various genotypes and phenotypes using a variety of genetic techniques.
Individuals classified according to their sex, racial origin, religion, common place of living, financial or social status, or some other cultural or behavioral attribute.
Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement. In biology, the term population growth is likely to refer to any known organism, but this article deals mostly with the application of the term to human populations in demography.
Increase, over a specific period of time, in the number of individuals living in a country or region.
The health outcomes of a group of individuals, including the distribution of such outcomes within the group.
Population health is not merely the sum of the health of individuals; it also entails consideration of the nature of the distribution of health throughout the population.
De facto population in a country, area or region as of 1 July of the year indicated. Figures are presented in thousands.
The percentage of de facto population living in areas classified as urban according to the criteria used by each area or country as of 1 July of the year indicated.
Age that divides the population in two parts of equal size, that is, there are as many persons with ages above the median as there are with ages below the median.
Computation of future changes in population numbers, given certain assumptions about future trends in the rates of fertility, mortality, and migration. Demographers often issue low, medium, and high projections of the same population, based on different assumptions of how these rates will change in the future.
The percentage of de facto population aged 60 years and older in a country, area or region as of 1 July of the year indicated.
The percentage of total population of a country, territory, or geographic area, 60 years of age and over, total or for a given sex and at a specific point of time, usually mid-year.
Also called proportion of population 60 years and older.
The percentage of de facto population aged 0-14 years in a country, area or region as of 1 July of the year indicated.
The percentage of total population of a country, territory, or geographic area, under 15 years of age, total or a given sex and at a specific point of time, usually mid-year.
Also called proportion of population less than 15 years old.
Approach to selection of clusters or households to be sampled, whereby more populous sections of the study area are allocated proportionately more clusters or households.
A population pyramid, also called age-sex pyramid and age structure diagram, is a graphical illustration that shows the distribution of various age groups in a human population (typically that of a country or region of the world), which normally forms the shape of a pyramid.
Graph of the sex and age-group distribution of the population. Used in mortality studies to observe possible alterations in the demographics of the population as a result of high mortality or population loss in a particular age group or sex.
Describes the situation in which a population may be composed of multiple sub-groups of different ethnicity; case and control group differences in the mix can confound the comparison and lead to spurious genetic associations.
A study of a group of individuals taken from the general population who share a common characteristic, such as age, sex, or health condition. This group may be studied for different reasons, such as their response to a drug or risk of getting a disease.
Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.
A position weight matrix (PWM), also called position-specific weight matrix (PSWM) or position-specific scoring matrix (PSSM), is a commonly used representation of motifs (patterns) in biological sequences.
Tabular numerical representations of sequence motifs displaying their variability as likelihood values for each possible residue at each position in a sequence. Position-specific scoring matrices (PSSMs) are calculated from position frequency matrices.
A positive correlation between two variables implies that as one variable gets bigger the value of the other variable also becomes bigger.
The ratio of the probability that an individual with the target condition has a positive test result to the probability that an individual without the target condition has a positive test result. This is the same as the ratio (sensitivity/1-specificity).
The positive predictive value, or precision rate, or post-test probability of disease, is the proportion of patients with positive test results who are correctly diagnosed. It is the most important measure of a diagnostic method as it reflects the probability that a positive test reflects the underlying condition being tested for. Its value does however depend on the prevalence of the disease, which may vary.
In screening/diagnostic tests: a measure of the usefulness of a screening/diagnostic test. It is the proportion of those with a positive test result who have the disease, and can be interpreted as the probability that a positive test result is correct. It is calculated as follows: PPV = Number with a positive test who have disease/Number with a positive test.
Ability of the case definition to identify real cases or the proportion of true cases of the disease that meet the case definition.
Ability of the surveillance system to detect real alerts, i.e. confirmed alerts (after verification)/all alerts detected.
A study with results indicating a beneficial effect of the intervention being studied. The term can generate confusion because it can refer to both statistical significance and the direction of effect; studies often have multiple outcomes; the criteria for classifying studies as negative or positive are not always clear; and, in the case of studies of risk or undesirable effects, ‘positive’ studies are ones that show a harmful effect.
The outcome of Bayesian statistical analysis. A probability distribution describing how likely different values of an outcome (e.g. treatment effect) are. It takes into account the belief before the study (the prior distribution) and the observed data from the study.
The probability of an event after a diagnostic result, that is, the updated prior probability. It can be calculated from the prior probability using Bayes's rule.
The prevention of infection or disease following exposure to a pathogen. This is most frequently addressed by administering a vaccine or anti-viral medication following exposure to a virus.
Surveillance of drugs, devices, appliances, etc., for efficacy or adverse effects, after they have been released for general sale.
The care provided a woman following the birth of a child.
The annual number of deaths of infants ages 28 days to 1 year per 1,000 live births in a given year.
A ratio expressing the number of deaths among children from 28 days up to but not including 1 year of age during a given time period divided by the number of lives births reported during the same time period. The postneonatal mortality rate is usually expressed per 1,000 live births.
In females, the period that is shortly after giving birth (parturition).
Also called postpartum period, puerperium.
A live birth or stillbirth that takes place after 42 completed weeks of gestational age.
The odds that the patient has the target disorder after the test is carried out (pre-test odds x likelihood ratio).
The proportion of patients with that particular test result who have the target disorder (post test odds/[1 + post-test odds]).
In statistics: the probability of rejecting the null hypothesis when a specific alternative hypothesis is true. The power of a hypothesis test is one minus the probability of Type II error. In clinical trials, power is the probability that a trial will detect, as statistically significant, an intervention effect of a specified size. If a clinical trial had a power of 0.80 (or 80%), and assuming that the pre-specified treatment effect truly existed, then if the trial was repeated 100 times, it would find a statistically significant treatment effect in 80 of them. Ideally we want a test to have high power, close to maximum of one (or 100%). For a given size of effect, studies with more participants have greater power. Studies with a given number of participants have more power to detect large effects than small effect. (Also called statistical power.)
Research that is grounded in, informed by, and intended to improve practice with the goal of improving the health of patients.
Directions or principles presenting current or future rules of policy for assisting health care practitioners in patient care decisions regarding diagnosis, therapy, or related clinical circumstances. The guidelines may be developed by government agencies at any level, institutions, professional societies, governing boards, or by the convening of expert panels. The guidelines form a basis for the evaluation of all aspects of health care and delivery.
Practice guideline [MeSH - publication type]: work consisting of a set of directions or principles to assist the health care practitioner with patient care decisions about appropriate diagnostic, therapeutic, or other clinical procedures for specific clinical circumstances. Practice guidelines may be developed by government agencies at any level, institutions, organizations such as professional societies or governing boards, or by the convening of expert panels. They can provide a foundation for assessing and evaluating the quality and effectiveness of health care in terms of measuring improved health, reduction of variation in services or procedures performed, and reduction of variation in outcomes of health care delivered.
A trial that aims to test a treatment policy in a 'real life' situation, when many people may not receive all of the treatment, and may use other treatments as well. This is as opposed to an explanatory trial, which is done under ideal conditions and is trying to determine whether a therapy has the ability to make a difference at all (i.e. testing its efficacy).
The precautionary principle states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking the action.
Expresses the conditions for decisions to implement prevention: scientific uncertainty, an acceptable balance of benefits and harms, and responsibility.
In statistics: a measure of the likelihood of random errors in the results of a study, meta-analysis or measurement. The greater the precision, the less random error. Confidence intervals around the estimate of effect from each study are one way of expressing precision, with a narrower confidence interval meaning more precision.
In trial searching: the proportion of relevant articles identified by a search strategy expressed as a percentage of all articles (relevant and irrelevant) identified by that strategy. Highly sensitive strategies tend to have low levels of precision. It is calculated as follows: Precision = Number of relevant articles/Number of articles identified. Also called positive predictive value.
Refers to the testing of experimental drugs in the test tube or in animals - the testing that occurs before trials in humans may be carried out.
Preclinical testing of drugs in experimental animals or in vitro for their biological and toxic effects and potential clinical applications.
Preclinical research is research in basic science, which precedes the clinical trials, and is almost purely based on theory and animal experiments.
Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.
A situation or condition that may increase a person's risk of developing a certain disease or disorder.
The frequency with which a positive diagnostic test actually signifies disease.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
Also called predictive value of tests.
The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth.
Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.
A teenaged or underaged girl (usually within the ages of 13–19) becoming pregnant.
Pregnancy in human adolescent females under the age of 19.
Also called adolescent pregnancy, teenage pregnancy.
Results of conception and ensuing pregnancy, including live birth; stillbirth; spontaneous abortion; induced abortion. The outcome may follow natural or artificial insemination or any of the various assisted reproductive techniques, such as embryo transfer or fertilization in vitro.
The ratio of the number of conceptions (conception) including live birth; stillbirth; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.
The death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the cause of death.
The three approximately equal periods of a normal human pregnancy. Each trimester is about three months or 13 to 14 weeks in duration depending on the designation of the first day of gestation.
The term used when the couple is able to conceive, but unable to produce a live birth.
A preconceived judgment made without adequate evidence and not easily alterable by presentation of contrary evidence.
Onset of obstetric labor before term (term birth) but usually after the fetus has become viable. In humans, it occurs sometime during the 29th through 38th week of pregnancy. Tocolysis inhibits premature labor and can prevent the birth of premature infants (infant, premature).
Also called premature obstetric labor, preterm labor
Rupture before onset of labor.
Spontaneous tearing of the membranes surrounding the fetus any time before the onset of obstetric labor. Preterm PROM is membrane rupture before 37 weeks of gestation.
Activities and measures taken in advance to ensure effective response to the impact of hazards, including the issuance of timely and effective early warnings and the temporary evacuation of people and property from threatened locations.
Pre-disaster activities, including an overall strategy, policies, and institutional and management structures, that are geared to helping at-risk communities safeguard their lives and assets by being alert to hazards and taking appropriate action in the face of an imminent threat or the actual onset of a disaster.
In this case, to the simple pre-post design a comparison/control group is added that undergoes the same evaluation procedures as before but does not receive the intervention. With this design one can demonstrate that the effects are most likely due to the intervention, but some critics could still say that there were pre-selection or context effects that made the intervention group more likely to show results than the comparison/control group: e.g. having less risk factors.
The pre- and post-test design (also called naturalistic design) is a simple way to plan an outcome evaluation without the benefits of a control group. In this design, the only people measured are those who receive the intervention. They are tested on their knowledge, attitudes or intentions, for example, before and after the intervention. The differences between the two measurements are then checked for statistical significance. The advantage of this design is its simplicity and the fact that it is not very time consuming. The major drawback is that without a control group, it is difficult to know whether the results are really due to the intervention, or to some other confounding factors.
A child between the ages of 2 and 5.
A live birth or stillbirth that takes place after at least 20 but before 37 completed weeks of gestational age.
Delivery before 37 completed weeks of gestation (less than 259 days).
Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother's last menstrual period, or 245 days after fertilization).
Also called premature birth, preterm delivery.
Rupture before onset of labor and leading to a preterm delivery.
A preliminary study to test the feasibility and appropriateness of a questionnaire, before implementing the study proper.
The odds of the target condition being present before the results of a diagnostic test are available.
The odds that the patient has the target disorder before the test is carried out (pre-test probability/[1 – pre-test probability]).
An experimental research design in which measurements of the groups are made both before and after an intervention.
The probability of the target condition being present before the results of a diagnostic test are available.
The proportion of people with the target disorder in the population at risk at a specific time (point prevalence) or time interval (period prevalence). Prevalence may depend on how a disorder is diagnosed.
In epidemiology, the prevalence of a disease in a statistical population is defined as the total number of cases of the disease in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population. It is used as an estimate of how common a condition is within a population over a certain period of time.
The overall occurrence of a particular condition in a specific population at a specific point of time.
The proportion of a population having a particular condition or characteristic: e.g. the percentage of people in a city with a particular disease, or who smoke.
Prevalence is the proportion of people in a population who have some attribute or condition at a given point in time or during a specified time period.
The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time.
The number of children who, from birth until the end of the forth month of life, are fed exclusively breast milk, expressed as a percentage of the corresponding mid-year population, for a given year, in a given country, territory, or geographic area.
The number of prevalent cases of moderate and severe nutritional deficiency in children under 5 year of age detected in a given year, expressed as a percentage of the corresponding mid-year population, for a given country, territory, or geographic area. Under-5 moderate and severe nutritional deficiency is defined as any weight-for-age (W/A) ratio less than minus two standard deviations (-2SD) from the reference median.
The number women aged 15 to 49 years who use any type of contraceptive method, at a specific point in time, expressed as a percentage of the corresponding mid-year population, for a given year, in a given country, territory, or geographic area. Contraceptive methods include female and male sterilization, injectable and oral contraceptives, intrauterine devices, diaphragms, spermicides, condoms, rhythm method and withdrawal.
The number of people having a particular disease at a given point in time per 1,000 population at risk.
The proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time.
A type of cross-sectional study that measures the prevalence of a characteristic.
In medicine, action taken to decrease the chance of getting a disease or condition.
An intervention or interventions that interrupts the web of causality leading to one or more aspects of ill health.
Refers to trials to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.
Services designed for health promotion and prevention of disease.
Prevention intervention describes an activity that will be carried out in order to prevent substance use behavior. Prevention interventions can be realized in different settings and with different methods and contents. The duration can vary between one-off activities and long-term projects running for several months or more.
Preventive medicine or preventive care refers to measures taken to prevent diseases (or injuries) rather than curing them or treating their symptoms.
A medical specialty primarily concerned with prevention of disease (primary prevention) and the promotion and preservation of health in the individual.
A term used to describe bioethical principles as neither rules of thumb nor absolute prescriptions but rather as binding in all cases unless an obligation found in one principle conflicts with another. In such situations, balancing of competing principles is undertaken using the technique of specification.
Medical care provided by the clinician of first contact for the patient. Typically, the primary care physician is a general practitioner, family practitioner, primary care internist, or primary care pediatrician. Primary care may also be administered by health professionals other than physicians, notably specially trained nurses (nurse practitioners) and paramedics. Usually, a general practitioner, family practitioner, nurse practitioner, or paramedic provides only primary care services, but an individual with specialty qualifications may provide primary care, alone or in combination with referral services. Thus, it is the nature of the contact (first vs. referred) that determines the care designation rather than the qualifications of the practitioner.
The first level contact with people taking action to improve health in a community.
Essential health care based on practical, scientifically sound and socially acceptable methods and technology made universally accessible to individuals and families in the community through their full participation and at a cost that the community and the country can afford to maintain at every stage of their development in the spirit of self-determination.
Primary care is that aspect of a health services system that assures person focused care over time to a defined population, accessibility to facilitate receipt of care when it is first needed, comprehensiveness of care in the sense that only rare or unusual manifestations of ill health are referred elsewhere, and coordination of care such that all facets of care (wherever received) are integrated.
Care which provides integrated, accessible health care services by clinicians who are accountable for addressing a large majority of personal health care needs, developing a sustained partnership with patients, and practicing in the context of family and community.
Also called primary health care.
Research that is grounded in, informed by, and intended to improve primary care practice with the goal of improving the health of patients.
Research directed at understanding and improving the primary care function as defined by the Institute of Medicine ("the provision of integrated, accessible healthcare services by clinicians that are accountable for addressing a large majority of personal healthcare needs, developing a sustained partnership with patients, and practicing within the context of family and community"). Primary care research includes theoretical and methodological research, health care research (investigations of the components of the primary care function itself), clinical research, and health systems research (including educational research, translational research, and health policy research).
Medical care facility that offers first contact health care only. Patients requiring specialized medical care are referred elsewhere. Some primary care centers provide a mixture of primary and referred care. Thus, it is the nature of the service provided (first contact) rather than the setting per se that distinguishes primary from more advanced levels of care.
The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group). What the primary endpoint will be is decided before the study begins.
Primary infertility means that the couple has never conceived, despite regular unprotected intercourse for a period of 12 months (medical definition).
Percentage of women who have been married for the past five years, who have ever had sexual intercourse, who have not used contraception during the past five years, and who have not had any births (demographic definition).
The primary responsibility of one nurse for the planning, evaluation, and care of a patient throughout the course of illness, convalescence, and recovery.
The outcome of greatest importance.
Interruption of the chain of causality at a point or points before a physiological or psychological abnormality is identifiable.
Specific practices for the prevention of disease or mental disorders in susceptible individuals or populations. These include health promotion, including mental health; protective procedures, such as communicable disease control; and monitoring and regulation of environmental pollutants. Primary prevention is to be distinguished from secondary prevention and tertiary prevention.
Individual studies such as randomized controlled trials, cohort studies, case-control studies, cross-sectional studies, etc.
Any investigation study (or trial) that is designed to investigate a hypothesized cause-effect relation by modifying the supposed causal factor(s) in the study population. A trial is an umbrella term for a variety of designs, including uncontrolled trials, controlled trials and randomized controlled trials.
‘Original research’ in which data are first collected. The term ‘primary research’ is sometimes used to distinguish it from secondary research (reanalysis of previously collected data), meta-analysis and other ways of combining studies (such as economic analysis and decision analysis). However, because systematic reviews can provide answers not possible from individual studies they can also be considered to be primary research.
Also called primary level research.
Primary sources are reports of original studies or the raw data.
‘Original research’ in which data are collected. The term primary study is sometimes used to distinguish it from a secondary study (re-analysis of previously collected data), meta-analysis, and other ways of combining studies (such as economic analysis and decision analysis). (Also called original study.)
A woman pregnant for the first time.
Intervention at the most distal point in the chain of causality. It is certain that there is a web of interactions that determine the state of health, from those that are most distal to those that are most proximal. The most distal are likely to be the political context in which the determinants are operative, followed by aspects of policy (health, social, environmental), followed by the context of social as well as medical contacts in communities, followed by individual social and behavioral characteristics (such as social isolation and health behaviors), followed by physiological states such as are related to perceived stressors. When interventions are designed to prevent the occurrence of a risk state, they are known as primary prevention. In a web of determinants, several interventions might be considered “primary”. Primordial prevention occurs when there is a focus on a more antecedent primary preventive strategy. The most effective prevention focuses on the weakest part of the web and not necessarily on the most proximal.
Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.
Four prima facie principles remain at the centre of education and debate in bioethics: beneficence, nonmaleficence, respect for persons, and justice. They provide the source of rules for ethical decisions (for example, truth telling, privacy, informed consent, etc). Rules are not deduced from principles (that is, principlism) but rather arise from specification. Users of casuistry may also refer to principles when selecting maxims.
Principlism is a system of ethics based on the four moral principles of beneficence, nonmaleficence, respect for persons, and justice.
An approach to ethics that focuses on theories of the importance of general principles such as respect for autonomy, beneficence/nonmaleficence, and justice.
Also called principle-based ethics.
The probability of an event before new evidence. Bayes's rule specifies how prior probabilities are updated in the light of new evidence.
Diseases/conditions that have been identified to be of important/major public health concern.
Rationing is an unavoidable consequence of scarcity. If there are not sufficient resources to meet all “needs” then some needs must be left unmet and priority should be given to services that best meet one's objectives. Priority setting refers to the process of deciding which needs should be met and which needs cannot be met, at least not immediately.
What a person claims as protected from scrutiny by others unless the person chooses to reveal it. Respect for privacy means that a person should not normally be expected to reveal personal information, conditions, or behavior unless he/she chooses to reveal it. Violation of privacy requires ethical justification, for example, in cases where it is argued such violations protect others from greater harm.
The state of being free from intrusion or disturbance in one's private life or affairs.
Practice of a health profession by an individual, offering services on a person-to-person basis, as opposed to group or partnership practice.
A probabilistic cause is one that increases or decreases the chance (likelihood) that the effect will occur.cur.
The chance or likelihood of an event happening. Probability may vary in value from 0 (no chance) to 1 (certain). Researchers have to set the level of probability/certainty they are willing to accept for their findings.
The study of chance processes or the relative frequency characterizing a chance process.
The function that gives the probabilities that a variable equals each of a sequence of possible values. Examples include the binomial distribution, normal distribution and Poisson distribution.
All individuals have a known chance of selection. They may all have an equal chance of being selected, or, if a stratified sampling method is used, the rate at which individuals from several subsets are sampled can be varied so as to produce greater representation of some classes than of others. A probability sample is created by assigning an identity (label, number) to all individuals in the “universe” population, e.g., by arranging them in alphabetical order and numbering in sequence, or simply assigning a number to each, or by grouping according to area of residence and numbering the groups. The next step is to select individuals (or groups) for study by a procedure such as use of a table of random numbers (or comparable procedure) to ensure that the chance of selection is known.
The branch of mathematics concerned with analysis of random phenomena.
The branch of mathematics dealing with the purely logical properties of probability. Its theorems underlie most statistical methods.
An evaluation procedure that focuses on how care is delivered, based on the premise that there are standards of performance for activities undertaken in delivering patient care, in which the specific actions taken, events occurring, and human interactions are compared with accepted standards.
Process evaluation assesses the implementation of the intervention and its effects on the various participants. It questions how the intervention took place, whether it was performed in conformity with its design, and whether the designated target group was reached. The process evaluation will help to explain outcome data and to discuss improvement of the intervention in the future.
Process evaluation sets out to evaluate how successful the process of carrying out the health impact assessment was in practice. It is important as a source of learning, for quality improvement, and as a mechanism of quality assurance.
Process indicators relate the outputs of a project (its deliverables, structures created, opportunities given, materials published) to its operational objectives.
Aspects of the behavior or performance of the health care system or health facility and the nature of participation on the part of people its serves. These consist of two parts: behaviors of the professionals and participation of the people who relate to the system or facility. Behaviors of professionals include the spectrum of clinical care involving problem (or needs) recognition, the diagnostic process, the recommendation of treatment or management; and appropriate follow up. Participation of people who relate to the system includes utilization; understanding of recommendations, satisfaction with services rendered, and participation in decisions concerning strategies for management.
Management control systems for structuring health care delivery strategies around case types, as in DRGs, or specific clinical services.
Professional ethics concerns the moral issues that arise because of the specialist knowledge that professionals attain, and how the use of this knowledge should be governed when providing a service to the public.
The principles of proper conduct concerning the rights and duties of the professional, relations with patients or consumers and fellow practitioners, as well as actions of the professional and interpersonal relations with patient or consumer families.
Documents prepared by members of a public health discipline or representative professional society containing core values, duties (obligations), and virtues of the profession, sometimes in the form of general principles. Distinguished from guidelines for good scientific practices and from rules of professional etiquette, ethics guidelines are consensus documents, providing a foundation for discussion of issues arising in practice such as minimizing risks and protecting the welfare of research participants, maintaining public trust, protecting confidentiality and privacy, and obligations to communities.
MeSH Violation of laws, regulations, or professional standards.
The number of certified nurses available per every 10,000 inhabitants in a population, at a given year, for a given country, territory, or geographic area. Certified nurses not includes auxiliary and unlicensed personnel.
The possible consequences and outcomes of a disease and the frequency with which they can be expected to occur.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
Patient or study participant characteristics that confer increased or decreased risk of a positive or adverse outcome.
A study that enrolls patients at a point in time and follows them forward to determine the frequency and timing of subsequent events.
A baseline variable that is prognostic in the absence of intervention Unrestricted, simple randomization can lead to chance baseline imbalance in prognostic variables, which can affect the results and weaken the trial's credibility. Stratification and minimization protect against such imbalances.
A program is a series of related activities that give effect to policy.
The process of formulating, improving, and expanding educational, managerial, or service-oriented work plans (excluding computer program development).
A systematic method for collecting, analyzing, and using information to answer basic questions about projects, policies and programs.
Studies designed to assess the efficacy of programs. They may include the evaluation of cost-effectiveness, the extent to which objectives are met, or impact.
A project is a component of a program, and is a discrete activity often undertaken at a specific location.
A term used to describe pregnancies that exceed the upper limit of a normal gestational period. In humans, a prolonged pregnancy is defined as one that extends beyond 42 weeks (294 days) after the first day of the last menstrual period (menstruation), or birth with gestational age of 41 weeks or more.
In the design of experiments, a propensity score is the probability of a unit (e.g., person, classroom, school) being assigned to a particular condition in a study given a set of known covariates.
Conditional probability of exposure to a treatment given observed covariates.
The ratio of one value to another expressed as a fraction of one. For example, the proportion of women among patients with cardiovascular disease.
A type of ratio in which the numerator is included in the denominator. The ratio of a part to the whole, expressed as a "decimal fraction (e.g., 0.2), as a fraction (1/5), or, loosely, as a percentage (20%).
The number of deliveries assisted by trained personnel in a specific year, regardless of their site of ocurrence, expressed as a percentage of the total number of births in that same year, in a given country, territory, or geographic area. Trained staff includes medical obstetricians, physicians with training in delivery care, university midwives and nurses with training in delivery care and graduated midwives; it does not include traditional midwives trained or not.
The percentage of the population living below the international poverty line in a given country, territory, or geographic area, for a given sex and/or age group, at a specific period in time, usually a year. International poverty line is defined at less than US$1.08 a day at 1993 international prices, equivalent to US$1 in 1985 international prices, adjusted to local currency using purchasing power parities.
The percentage of the population living below the national poverty line in a given country, territory, or geographic area, at a specific period in time, usually a year. The operational definition for a national poverty line varies from country to country and represents the amount of income required by each household to meet the basic needs of all its members.
The number of pregnant women who have received at least one health care visit during pregnancy provided by a trained health worker, expressed as a percentage of the live birth population, at a given year, for a given country, territory, or geographic area. Health care visit during pregnancy is defined as those health care services for the control and monitoring of the pregnancy and ambulatory care for associated morbidity; it does not include neither direct vaccination activities nor the health care services rendered immediately prior to delivery. Trained staff includes medical obstetricians, physicians with training in delivery care, university midwives and nurses with training in delivery care and graduated midwives; it does not include traditional midwives trained or not.
The percentage of total population of a country, territory, or geographic area living in places defined as urban, at a specific point of time, usually mid-year. The term urban refers essentially to cities, towns, and other densely populated areas. The demarcation of urban areas is usually defined by countries as part of census procedures, and is usually based on the size of localities, and/or the classification of areas as administrative centers or in accordance to special criteria such as population density or type of economic activity of residents. There is no international agreed definition of urban areas, and national operational definitions may vary from country to country.
In survival analysis: a statistical model that asserts that the effect of the study factors (e.g. the intervention of interest) on the hazard rate (the risk of occurrence of an event, such as death, at a point in time) in the study population is multiplicative and does not change over time. (Also called Cox model.)
Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.
Fraction of all deaths due to a specific cause.
The proportion of deaths in a specified population over a period of time attributable to different causes. Each cause is expressed as a percentage of all deaths, and the sum of the causes must add to 100%. These proportions are not mortality rates, since the denominator is all deaths, not the population in which the deaths occurred.
A document written for the purpose of obtaining funding for a research project.
In medicine, a study or clinical trial in which participants are identified and then followed forward in time.
A research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome.
In evaluations of the effects of healthcare interventions, a study in which people are identified according to current risk status or exposure, and followed forwards through time to observe outcome. Randomized controlled trials are always prospective studies. Cohort studies are commonly either prospective or retrospective, whereas case-control studies are usually retrospective. In Epidemiology, 'prospective study’ is sometimes misused as a synonym for cohort study.
A study in which events or cases are observed or studied as they occur, or in which human subjects are identified and followed forward in time.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Ongoing collection of epidemiological data, with real-time analysis. Mortality surveillance systems usually rely on home visitors who record deaths in households on a weekly basis.
The plan or set of steps to be followed in a study. A protocol for a systematic review should describe the rationale for the review, the objectives, and the methods that will be used to locate, select, and critically appraise studies, and to collect and analyze data from the included studies.
Protocol is a set of directions or rules regarding a sequence of activities in a specified situation or setting. The directions are formulated in advance and are recorded in some way. The purpose of a protocol is to give a general structure for the activities and by doing so to help collaboration between persons, organizations and societies.
In terms of health technology assessment (HTA), a protocol is a detailed plan that, by providing a list of steps or procedures, guides the development of a full HTA report. A protocol usually contains an introduction, the objectives of the report, the methodology to be followed (e.g. inclusion criteria for clinical trials, methodology of data extraction and analysis), the role of each person involved in the process, a detailed search strategy and the time frame for all stages of the developing full HTA process. The objective of a protocol is to inform all stakeholders and other HTA agencies about the undertaken HTA report and avoid unnecessary doubling of the work. A protocol also enables a reviewer to verify whether the whole process has been carried out properly and, if yes, it enables others to update the search on the topic in question by using the search strategy determined in the protocol.
A written description of a change(s) to or formal clarification of a protocol.
A failure to adhere to the pre-specified trial protocol, or a participant for whom this occurred. Examples are participants found to have been included in the trial by mistake (they were ineligible) and those for whom the intervention or other procedure differed from that outlined in the protocol.
Extent that health care providers carry out the host of diagnostic tests, monitoring equipment, interventional requirements, and other technical specifications that define optimal patient management.
Psychosocial interventions include structured counseling, motivational enhancement, case management, care-coordination, psychotherapy and relapse prevention.
A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (fertility), development of secondary sex characteristics, and other changes seen in adolescent development.
The science and art of promoting health, preventing disease, and prolonging life through the organized efforts of society.
Public health is the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals.
Public health refers to all organized measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole.
Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.
Management of public health organizations or agencies.
Refers to public finance and provision of health care services.
A public health emergency (the condition that requires the governor to declare a state of public health emergency) is defined as "an occurrence or imminent threat of an illness or health condition, caused by bio terrorism, epidemic or pandemic disease, or (a) novel and highly fatal infectious agent or biological toxin, that poses a substantial risk of a significant number of human facilities or incidents or permanent or long-term disability. The declaration of a state of public health emergency permits the governor to suspend state regulations, change the functions of state agencies.
The systematic application of information and computer sciences to public health practice, research, and learning.
A public health intervention can be defined by the fact that it is applied to many, most, or all members in a community, with the aim of delivering a net benefit to the community or population as well as benefits to individuals. Public health interventions include policies of governments and non-government organizations; laws and regulations; organizational development; community development; education of individuals and communities; engineering and technical developments; service development and delivery; and communication, including social marketing.
Public health law focuses on legal issues in public health practice and on the public health effects of legal practice. Public health law typically has three major areas of practice: police power, disease and injury prevention, and the law of populations.
The field of nursing focusing on the health of the community through educational and preventive programs, as well as providing treatment and diagnostic services.
The activities and endeavors of the public health services in a community on any level.
The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community.
Public policy can be generally defined as the course of action or inaction taken by governmental entities (the decisions of government) with regard to a particular issue or set of issues.
A course or method of action selected, usually by a government, from among alternatives to guide and determine present and future decisions.
Occurs when the publication of research depends on the direction of the study results and whether they are statistically significant.
Publication bias is the bias that can result in a systematic review because studies with statistically significant results are more likely to be published than those that show no effect (particularly for intervention studies). Publication bias can be minimized if an attempt is made to include in a systematic review all relevant published and unpublished studies. This process can be facilitated by international registers of trials.
Bias produced when the published studies do not represent adequately all the studies carried out on a specific topic. Many facts can origin this bias, although the best known is the trend to publish statistically significant (p < 0.05) or clinically relevant (high magnitude albeit non-significant) results. Other variables influencing publication bias are sample size (more in small studies), type of design (less in well conducted randomized controlled trials), funding, conflict of interest, prejudice against an observed association (for example, cocaine consumption and non-adverse effect on fetus), sponsorship.
The influence of study results on the chances of publication and the tendency of investigators, reviewers, and editors to submit or accept manuscripts for publication based on the direction or strength of the study findings. Publication bias has an impact on the interpretation of clinical trials and meta-analyses. Bias can be minimized by insistence by editors on high-quality research, thorough literature reviews, acknowledgement of conflicts of interest, modification of peer review practices, etc.
Published erratum [MeSH - publication type]: work consisting of an acknowledgment of an error, issued by a publisher, editor, or author. It customarily cites the source where the error occurred, giving complete bibliographic data for retrieval. In the case of books and monographs, author, title, imprint, paging, and other helpful references will be given; in the case of journal articles, the author, title, paging, and journal reference will be shown. An erratum notice is variously cited as Errata or Corrigenda.
In qualitative research, a type of nonprobability sampling in which theory or personal judgment guide the selection of study participants who will be most representative of the population. Depending on the topic, examples include (1) maximum variation sampling, to document range or diversity; (2) extreme or deviant case sampling, in which one selects cases that are opposite in some way; (3) typical or representative case sampling, to describe and illustrate what is typical and common in terms of the phenomenon of interest; (4) critical sampling, to make a point dramatically; and (5) criterion sampling, in which all cases that meet some predetermined criteria of importance are studied. Table of contents:
A χ2 test to assess heterogeneity across the studies included in a meta-analysis, in which the effect size of study is compared with the pooled estimate. From the point of view of validity, power, and computational ease, this test of heterogeneity is the best choice.
The part of meta-analysis concerning with the appraisal of the methods used in each individual study.
A research approach that emphasizes the non-numerical data and interpretive analysis.
Qualitative research focuses on social and interpreted, rather than quantifiable, phenomena and aims to discover, interpret, and describe rather than to test and evaluate. Qualitative research makes inductive, descriptive inferences to theory concerning social experiences or settings, whereas quantitative research makes causal or correlational inferences to populations. Qualitative research is not a single method but a family of analytic approaches that rely on the description and interpretation of qualitative data. Specific methods include, for example, grounded theory, ethnography, phenomenology, case study, critical theory, and historiography.
Research that derives data from observation, interviews, or verbal interactions and focuses on the meanings and interpretations of the participants.
A vague notion of the methodological strength of a study, usually indicating the extent of bias prevention.
The number of years of expected life corrected for the quality of life that patients are expected to experience in those years.
A unit of measure for survival that accounts for the effects of suboptimal health status and the resulting limitations in quality of life. For example, if a patient lives for 10 years and his or her quality of life is decreased by 50% because of chronic lung disease, survival would be equivalent to 5 quality-adjusted life-years.
A measure that combines mortality and quality of life gains (outcome of a treatment measured as the number of years of life saved, adjusted for quality).
A summary measure of health gain that combines (changes in) life expectancy and quality of life. It uses health utilities to weight improvements in life expectancy according to the quality of life experienced. Thus, a given state of health (say living with chronic pain) may be assigned a utility of (say) 0.75. Living for 20 years in this state of health would then be considered equivalent to 15 QALYs (20×0.75) and an intervention that prevented people from entering this state would lead to a health gain of five QALYs.
A measurement index derived from a modification of standard life-table procedures and designed to take account of the quality as well as the duration of survival. This index can be used in assessing the outcome of health care procedures or services.
A system to ensure that the study is performed and the data are generated, recorded and reported in compliance with the protocol, good clinical practice and national regulations.
All those planned and systematic actions that are established to ensure that the trial is performed and the data are generated, documented (recorded), and reported in compliance with GCP and the applicable regulatory requirement(s).
System of procedures, checks, audits and corrective actions to ensure that all testing, sampling, analysis, monitoring and other technical and reporting activities are of the highest achievable quality.
Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps.
The operational techniques and activities undertaken within the quality assurance system to verify that the requirements for quality of the trial related activities have been fulfilled.
The supervision and control of all operations involved in a process usually involving sampling and inspection, in order to detect and correct systematic or excessively random variations in quality.
A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required.
An approach to defining, measuring, improving, and controlling practices to maintain or improve the appropriateness of health care services.
The global appraisal of a study according to a validated and pretested protocol. Nevertheless, given that different scales yield divergent results, analyses based on a summary score of quality should be interpreted with caution. It is easier in clinical trials than in observational studies. Reviewers should be blind for the information that could influence the evaluation (authors, institutions, journal, direction of the association, etc).
The extent to which health care meets technical and humanistic standards of optimal care.
The levels of excellence which characterize the health service or health care provided based on accepted standards of quality.
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and political science.
A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.
Refers to trials that explore ways to improve comfort and quality of life for individuals with a chronic illness.
The degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge.
A value assigned to represent the validity of a study either for a specific criterion, such as concealment of allocation, or overall. Quality scores can use letters (A, B, C) or numbers.
Quality standards are generally accepted principles or sets of rules for the best/most appropriate way to implement an interventions. Frequently they refer to structural (formal) aspects of quality assurance, such as environment and staff composition. However, they may also refer to process aspects such as adequacy of content, process of the intervention or evaluation processes.
A research approach that emphasizes the collection of numerical data or data than can be quantified, and statistical analysis.
The investigation of phenomena that lend themselves to test well-specified hypotheses through precise measurement and quantification of predetermined variables that yield numbers suitable for statistical analysis.
Methods of allocating people to a trial that are not random, but were intended to produce similar groups when used to allocate participants. Quasi-random methods include: allocation by the person's date of birth, by the day of the week or month of the year, by a person's medical record number, or just allocating every alternate person. In practice, these methods of allocation are relatively easy to manipulate, introducing selection bias.
A trial using a method of allocating participants to different forms of care that is not truly random; for example, allocation by date of birth, day of the week, medical record number, month of the year, or the order in which participants are included in the study (e.g. alternation).
A means of collecting data from people where they provide written responses to a set of questions, either in their own words (open-ended questions), or by selecting from among pre-defined answers (closed response questions).
Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument. Table of contents:
A mortality rate limited to a specified racial group. Both numerator and denominator are limited to the specified group.
Governed by chance.
A method that uses the play of chance to assign participants to comparison groups in a trial, e.g. by using a random numbers table or a computer-generated random sequence. Random allocation implies that each individual or unit being entered into a trial has the same chance of receiving each of the possible interventions. It also implies that the probability that an individual will receive a particular intervention is independent of the probability that any other individual will receive the same intervention.
A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.
The arbitrary process through which eligible study participants are assigned to either a control group or the group of people who will receive the intervention.
In meta-analysis: a statistical model in which both within-study sampling error (variance) and between-studies variation are included in the assessment of the uncertainty (confidence interval) of the results of a meta-analysis. When there is heterogeneity among the results of the included studies beyond chance, random-effects models will give wider confidence intervals than fixed-effect models.
A method of combining individual effect sizes in which heterogeneity is incorporated into the pooled estimate by including a between study component of variance. It assumes that the sample of studies included in the analysis is drawn from a population of studies. The random effects model does not assume homogeneity of the effects across the studies being pooled—that is, each sample of studies has a true effect size. There is no agreement on whether this model is more suitable than the fixed effects model to combine individual studies.
Error due to the play of chance. Confidence intervals and P-values allow for the existence of random error, but not systematic errors (bias).
A method of randomization that ensures that, at any point in a trial, roughly equal numbers of participants have been allocated to all the comparison groups. Permuted blocks should be used in trials using stratified randomization. (Also called block randomization.)
A group of people selected for a study that is representative of the population of interest. This means that everyone in the population has an equal chance of being approached to participate in the survey, and the process is meant to ensure that a sample is as representative of the population as possible. It has less bias than a convenience sample: that is, a group that the researchers have more convenient access to. Randomized trials are rarely carried out on random samples.
A sample derived by selecting individuals such that each individual has the same probability of selection.
The process of randomly allocating participants into one of the arms of a controlled trial. There are two components to randomization: the generation of a random sequence, and its implementation, ideally in a way so that those entering participants into a study are not aware of the sequence (concealment of allocation).
A method based on chance by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant.
When referring to an experiment or clinical trial, the process by which animal or human subjects are assigned by chance to separate groups that compare different treatments or other interventions. Randomization gives each participant an equal chance of being assigned to any of the groups.
The process of assigning trial subjects to treatment or control groups using an element of chance to determine the assignments in order to reduce bias.
A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.
A study in which participants are randomly (i.e., by chance) assigned to one of two or more treatment arms of a clinical trial. Occasionally placebos are utilized.
An experiment in which two or more interventions, possibly including a control intervention or no intervention, are compared by being randomly allocated to participants. In most trials one intervention is assigned to each individual but sometimes assignment is to defined groups of individuals (for example, in a household) or interventions are assigned within individuals (for example, in different orders or to different parts of the body).
Clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.
Randomized controlled trial [MeSH - publication type]: work consisting of a clinical trial that involves at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.
In a group of scores, the range is the difference between the maximum and minimum scores.
In statistics, the difference between the largest and smallest values in a distribution. In common use, the span of values from smallest to largest.
The speed or frequency of occurrence of an event, usually expressed with respect to time. For instance, a mortality rate might be the number of deaths per year, per 100,000 people.
An expression of the frequency with which an event occurs in a defined population.
A rate ratio in epidemiology is calculated to compare the ratio of events occurring at any given point in time. Rate Ratio = Incidence Rate 1/Incidence Rate 2
A comparison of two groups in terms of incidence rates, person-time rates, or mortality rates.
A numerical expression of the relationship between one set of frequencies and another. An example is the ratio of males to females in a sample.
The value obtained by dividing one quantity by another.
Reasoning refers to the process of drawing inferences or conclusions from premises, facts, or other evidence.
A bias arising from mistakes in recollecting events, both because of failures of memory, and looking at things 'with hindsight' and possibly changed views. People's reports of what is happening to them currently, therefore, can be more accurate than their recall of what happened two years ago and how they felt about it at the time. This bias is a threat to the validity of retrospective studies.
Bias due to imperfect recall by questionnaire respondents of events in their households. Usually results in an under-estimation of mortality.
Period of interest in the measurement of a mortality rate, i.e. the interval of time to which the mortality rate in a given population refers.
The commitment in writing, as authentic evidence, of something having legal importance. The concept includes certificates of birth, death, etc., as well as hospital, medical, and other institutional records.
The process of getting participants into a randomized trial.
The period during which a trial is attempting to identify and enroll participants. Recruitment activities can include advertising and other ways of soliciting interest from possible participants.
Indicates the current stage of a trial, whether it is planned, ongoing, or completed.
The spontaneous termination of three or more pregnancies before the 20th week of gestation.
Habitual abortion, recurrent miscarriage or recurrent pregnancy loss (RPL) is the occurrence of repeated (three or more consecutive) pregnancies that end in miscarriage of the fetus, usually before 20 weeks of gestation.
Three or more consecutive spontaneous abortions.
A technique for determining the optimal way of using a set of predictor variables to estimate the likelihood of an individual experiencing a particular outcome. The technique repeatedly divides the population (e.g., old vs. young; among young and old, the men and the women; and so on) according to their status on variables that discriminate between those who will have the outcome of interest and those who will not.
A short note detailing the source of information or a quoted passage.
The population that the results of a study can be generalized to.
A standardized object or substance which is used as a measurement base for similar objects or substances.
A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.
In health-related fields, a reference range (or reference values or interval) is a set of values of some measurement that a physician or other health professional can use to interpret a set of results for a particular patient. It is determined by collecting data from vast numbers of laboratory tests.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
The practice of sending a patient to another program or practitioner for services or advice which the referring source is not prepared to provide.
Occurs when characteristics of patients differ between one setting (e.g., primary care) and another setting that includes only referred patients (e.g., secondary or tertiary care).
Medical care provided to a patient when referred by one health professional to another with more specialized qualifications or interests. There are two levels of referred care: secondary and tertiary. Secondary care is usually provided by a broadly skilled specialist such as a general surgeon, general internist, or obstetrician.
In qualitative research using field observation, whichever of the three approaches used, the observer will always have some effect on what is being observed, small or large. This interaction of the observer with what is observed is called reflexivity. Whether it plays a positive or negative role in accessing social truths, the researcher must acknowledge and investigate reflexivity and account for it in data interpretation.
An awareness of the researcher's contribution to the construction of meanings throughout the research process, and an acknowledgment of the impossibility of remaining ‘outside of’ one's subject matter while conducting research.
A treatment plan that specifies the dosage, the schedule, and the duration of treatment.
Planning for health resources at a regional or multi-state level.
The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.
A statistical modeling technique used to estimate or predict the influence of one or more independent variables on a dependent variable, e.g. the effect of age, sex, and educational level on the prevalence of a disease. Logistic regression and meta-regression are types of regression analysis.
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see linear models) the relationship is constrained to be a straight line and least-squares analysis is used to determine the best fit. in logistic regression (see logistic models) the dependent variable is qualitative rather than continuously variable and likelihood functions are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
The term used to signify the amount by which a change in one variable must be multiplied to give the corresponding average change in the other variable. It represents the degree to which the regression line slopes upwards or downwards.
An equation to describe the correlation between two variables, meaning that when one of them changes by a certain amount the other changes on the average by a certain amount.
A line drawn on a scatter diagram, to illustrate the degree and direction of the correlation between two variables.
A phenomenon where, upon re-measurement, previous extreme (very high or low) scores tend to move towards (regress to) the average score.
Bodies having the power to regulate. In the ICH GCP guidance, the expression "Regulatory Authorities" includes the authorities that review submitted clinical data and those that conduct inspections. These bodies are sometimes referred to as competent authorities.
The proportional increase in rates of good outcomes between experimental and control participants. It is calculated by dividing the rate of good outcome in the experimental group (experimental event rate, or EER) minus the rate of good outcome in the control group by the rate of good outcome in the control group.
The diagnostic odds ratio is a single value that provides one way of representing the power of the diagnostic test. It is applicable when we have a single cut point for a test and classify tests results as positive and negative. The diagnostic odds ratio is calculated as the product of the true positive and true negative divided by the product of the false positives and false negatives. The relative diagnostic odds ratio is the ratio of one diagnostic odds ratio to another.
The absolute difference (risk difference) in rates of harmful outcomes between experimental groups (experimental event rate, or EER) and control groups (control event rate, or CER), calculated as the rate of harmful outcome in the control group minus the rate of harmful outcome in the experimental group (CER – EER). Typically used to describe a beneficial exposure or intervention (e.g., if 20% of patients in the control group have an adverse event, as do 10% among treated patients, the ARR or risk difference would be 10% expressed as a percentage or 0.10 expressed as a proportion).
Relative poverty defines poverty in terms of its relation to the standards that exist elsewhere in society.
A measure of relative poverty defines "poverty" as being below some relative poverty threshold.
The ratio of the incidence of the outcome in the exposed group to the incidence of the outcome in the unexposed group.
A comparison of the risk of some health-related event such as disease or death in two groups.
The proportional increase in rates of harmful outcomes between experimental and control participants. It is calculated by dividing the rate of harmful outcome in the experimental group (experimental event rate, or EER) minus the rate of harmful outcome in the control group (control event rate, or CER) by the rate of harmful outcome in the control group ([EER – CER]/CER). Typically used with a harmful exposure.
The proportional reduction in risk in one treatment group compared to another. It is one minus the risk ratio. If the risk ratio is 0.25, then the relative risk reduction is 1-0.25=0.75, or 75%.
In epidemiology, the relative survival rate (RSR) is defined as the ratio of observed survival in a population to the expected survival rate.
Resource-based relative value scale (RBRVS) is a schema used to determine how much money medical providers should be paid.
Coded listings of physician or other professional services using units that indicate the relative value of the various services they perform. They take into account time, skill, and overhead cost required for each service, but generally do not consider the relative cost-effectiveness. Appropriate conversion factors can be used to translate the abstract units of the relative value scales into dollar fees for each service based on work expended, practice costs, and training costs.
Relevance refers to whether the research is appropriate to the identified review question and whether the study findings are transferable (generalizable) to the population or setting whom the question concerns.
The degree to which results obtained by a measurement procedure can be replicated. Lack of reliability can arise from divergences between observers or measurement instruments, measurement error, or instability in the attribute being measured.
The extent to which an observation that is repeated in the same stable population yields the same result (i.e. test–retest reliability). Also, the ability of a single observation to distinguish consistently among individuals in a population.
Reliability is the degree to which observations or measures can be replicated, when repeated under the same conditions.
A strategy for changing clinician behavior. Manual or computerized reminders to prompt behavior change.
Systems used to prompt or aid the memory. The systems can be computerized reminders, color coding, telephone calls, or devices such as letters and postcards.
Do the same thing to other people in order to achieve the same outcomes that occurred in a study. Also, repeating the circumstances of a study to test whether the results and outcomes are similar in another sample or population.
To implement a program in a setting other than the one for which it originally was designed and implemented, with attention to the faithful transfer of its core elements to the new setting.
A bias caused by only a subset of all the relevant data being available. The publication of research can depend on the nature and direction of the study results. Studies in which an intervention is not found to be effective are sometimes not published. Because of this, systematic reviews that fail to include unpublished studies may overestimate the true effect of an intervention. In addition, a published report might present a biased set of results (e.g. only outcomes or sub-groups where a statistically significant difference was found. (Also called publication bias.)
Bias due to (often intentional) under- or over-reporting of information, such as number of deaths or household size.
A sample that accurately reflects the characteristics of the population from which it is drawn. It is a precise miniaturized representation of the proportion of elements of the population.
A sample whose characteristics correspond to those of the original population or reference population.
Ability of the system to accurately describe the occurrence of a health-related event by place and person over time in a given population.
Refers to the ability of a test or experiment to be accurately reproduced, or replicated, by someone else working independently.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
The biological process by which new "offspring" individual organisms are produced from their "parents".
The total process by which organisms produce offspring.
Human behavior or decision related to reproduction.
Substances used either in the prevention or facilitation of pregnancy.
Within the framework of WHO's definition of health as a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity, reproductive health, or sexual health/hygiene, addresses the reproductive processes, functions and system at all stages of life. Reproductive health, therefore, implies that people are able to have a responsible, satisfying and safer sex life and that they have the capability to reproduce and the freedom to decide if, when and how often to do so. Implicit in this are the right of men and women to be informed of and to have access to safe, effective, affordable and acceptable methods of fertility regulation of their choice; and the right of access to appropriate health care services that will enable women to go safely through pregnancy and childbirth and provide couples with the best chance of having a healthy infant.
Health care services related to human reproduction and diseases of the reproductive system. Services are provided to both sexes and usually by physicians in the medical or the surgical specialities such as reproductive medicine; andrology; gynecology; obstetrics; and perinatology.
An important aggregate factor in epidemiological studies of women's health. The concept usually includes the number and timing of pregnancies and their outcomes, the incidence of breast feeding, and may include age of menarche and menopause, regularity of menstruation, fertility, gynecological or obstetric problems, or contraceptive usage.
A branch of medicine that deals with prevention, diagnosis and management of reproductive problems; goals include improving or maintaining reproductive health and allowing people to have children at a time of their choosing. It is founded on knowledge of reproductive anatomy, physiology, and endocrinology, and incorporates relevant aspects of molecular biology, biochemistry and pathology.
A medical-surgical specialty concerned with the morphology, physiology, biochemistry, and pathology of reproduction in man and other animals, and on the biological, medical, and veterinary problems of fertility and lactation. It includes ovulation induction, diagnosis of infertility and recurrent pregnancy loss, and assisted reproductive technologies such as embryo transfer, in vitro fertilization, and intrafallopian transfer of zygotes.
Reproductive rights rest on the recognition of the basic right of all couples and individuals to decide freely and responsibly the number, spacing and timing of their children and to have the information and means to do so, and the right to attain the highest standard of sexual and reproductive health. They also include the right of all to make decisions concerning reproduction free of discrimination, coercion and violence.
The search for knowledge or any systematic investigation to establish facts.
Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws.
A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly.
Research ethics involves the application of fundamental ethical principles to a variety of topics involving scientific research. These include the design and implementation of research involving human experimentation, animal experimentation, various aspects of academic scandal, including scientific misconduct (such as fraud, fabrication of data and plagiarism), whistleblowing; regulation of research, etc.
The moral obligations governing the conduct of research. Used for discussions of research ethics as a general topic.
The evaluation by experts of the quality and pertinence of research or research proposals of other experts in the same field. Peer review is used by editors in deciding which submissions warrant publication, by granting agencies to determine which proposals should be funded, and by academic institutions in tenure decisions.
Those individuals engaged in research.
A document describing in detail how a research study is to be conducted in practice, including the methodology, a plan for analysing the results, and a budget.
A research question is the methodological point of departure of scholarly research in both the natural sciences and humanities.
The main question a research project aims to answer.
Persons who are enrolled in research studies or who are otherwise the subjects of research.
Financial support of research activities.
The sequence of events through which a proven scientific discovery moves in a bidirectional fashion between basic scientists, clinical researchers, practitioners, and consumers of health care services.
Also called knowledge translation.
Interaction between research personnel and research subjects.
Unknown, unmeasured, or suboptimally measured prognostic factors that remain unbalanced between groups after full covariable adjustment by statistical techniques. The remaining imbalance will lead to a biased assessment of the effect of any putatively causal exposure.
Resource allocation is used to assign the available resources in an economic way.
Societal or individual decisions about the equitable distribution of available resources.
Resource costs of a health intervention or program include: capital costs (new and existing buildings or equipment); staffing costs (physicians, nurses, physiotherapists, etc); consumable costs (drugs, dressings, etc); non-patient related costs (administration and overhead costs); costs incurred in non-health care sectors (social services, etc); and costs incurred by patients and their families (transportation, parking, child care, etc). Each of these components must be identified, measured and valued. The range of costs (and benefits) included in a particular economic evaluation depends upon the perspective taken, which could be that of the individual patient or provider, hospital, health authority, health insurer or society.
Considered by some the “cardinal principle of modern research ethics”. In addition to respect for autonomy and freedom from coercion, it includes consideration of the human condition, cultural sensitivity by researchers, and protecting persons, not only from physical harm, but also from demeaning or disrespectful actions or situations.
A prima facie principle in bioethics underlying the obligation for informed consent in research and decisions regarding study design and interventions. From the Kantian tradition: persons should be treated as ends in themselves and not as means to an end. Implies two distinct moral requirements: acknowledge autonomy and protect those with diminished autonomy.
Any procedure used with random assignment to achieve balance between study groups in size or baseline characteristics. Blocking is used to ensure that comparison groups will be of approximately the same size. With stratification, randomization with restriction is carried out separately within each of two or more subsets of participants (for example, defining disease severity or study centers) to ensure that the patient characteristics are closely balanced within each intervention group.
Retracted publication [MeSH - publication type]: work consisting of a designation of an article or book as retracted in whole or in part by an author or authors or an authorized representative. It identifies a citation previously published and now retracted through a formal issuance from the author, publisher, or other authorized agent, and is distinguished from retraction of publication, which identifies the citation retracting the original published item.
Authors' withdrawal or disavowal of their participation in performing research or writing the results of their study.
Retraction of publication [MeSH - publication type]: work consisting of a statement issued by one or more authors of an article or a book, withdrawing or disavowing acknowledgment of their participation in performing research or writing the results of their study. in indexing, the retraction is sent to the editor of the publication in which the article appeared and is published under the rubric "retraction" or in the form of a letter. this publication type designates the author's statement of retraction: it should be differentiated from retracted publication which labels the retracted publication.
Looking back at events that have already taken place.
A research study in which the medical records of groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) are compared for a particular outcome. Also called a historic cohort study.
A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition. For example, one group may have been exposed to a particular substance that the other was not. Also called a case-control study.
A study in which the outcomes have occurred to the participants before the study commenced. Case-control studies are usually retrospective, cohort studies sometimes are, randomized controlled trials never are.
A study that looks at events that took place in the past; can involve extracting information from medical records or interviewing patients about past events or behavior.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Study of past mortality in a population using a standardized questionnaire that is administered to the entire population or, more commonly, to a randomly selected sample.
A systematic review or a review article in the medical literature which summarizes a number of different studies and may draw conclusions about a particular intervention. Review articles are often not systematic. Review articles are also sometimes called overviews.
Review [MeSH - publication type]: an article or book published after examination of published material on a subject. It may be comprehensive to various degrees and the time range of material scrutinized may be broad or narrow, but the reviews most often desired are reviews of the current literature. The textual material examined may be equally broad and can encompass, in medicine specifically, clinical material as well as experimental research or case reports. State-of-the-art reviews tend to address more current matters.
These are systematic and explicit methods to identify, select, and critically appraise relevant findings from systematic reviews and/or meta-analyses. They may also include individual studies (i.e. randomized controlled trials).
For an article to be accepted for publication in a medical journal it must undergo a review process. Each journal creates its own process, but they have certain common characteristics in general. There are various general "levels" of scrutiny, which have some effect on the respect given to articles published in the journals. Some broad categories might be editorial review, peer review, and blind peer review.
Justified claims made by individuals or groups upon others and based on a system of rules authorizing us to affirm or demand what is due. Possessing a right validly constrains others from interfering with the exercise of that right. Moral rights are claims justified by moral principles and are correlated with obligations. In public health, a broadly defined set of human rights are often asserted.
The proportion of participants experiencing the event of interest. Thus, if out of 100 participants the event (e.g. a stroke) is observed in 32, the risk is 0.32. The control group risk is the risk amongst the control group. The risk is sometimes referred to as the event rate, and the control group risk as the control event rate. However, these latter terms confuse risk with rate. Statistical texts in particular are happy to discuss risk of beneficial effects as well as adverse events.
The chance of probability that an event will occur.
The probability that an event will occur, e.g. that an individual will become ill or die within a stated period of time or age.
The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.
The use of severity-of-illness measures, such as age, to estimate the risk (measurable or predictable chance of loss, injury or death) to which a patient is subject before receiving some health care intervention. This adjustment allows comparison of performance and quality across organizations, practitioners, and communities.
The use of the factual base to define the health effects of exposure of individuals or populations to hazardous materials and situations.
The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences.
The risk to individual participants versus the potential benefits. The risk/benefit ratio may differ depending on the condition being treated.
The difference in size of risk between two groups. For example, if one group has a 15% risk of contracting a particular disease, and the other has a 10% risk of getting the disease, the risk difference is five percentage points. (Also called absolute risk difference, absolute risk reduction.)
A factor that is believed to increase the probability of a certain outcome or illness.
An aspect of a person's condition, lifestyle or environment that affects the probability of occurrence of a disease. For example, cigarette smoking is a risk factor for lung cancer.
An aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that is associated with an increased occurrence of disease or other health-related event or condition.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Risk management entails options for avoiding, reducing or treating the risks, consideration of their costs and benefits, and the adequacy of contingency plans. It also includes discussion of how differing perceptions of risk can be mediated and whether future health risks can be predicted.
The process of minimizing risk to an organization by developing systems to identify and analyze potential hazards to prevent accidents, injuries, and other adverse occurrences, and by attempting to handle events and incidents which do occur in such a manner that their effect and cost are minimized. Effective risk management has its greatest benefits in application to insurance in order to avert or minimize financial liability.
A comparison of the risk of some health-related event such as disease or death in two groups.
In signal detection theory, a receiver operating characteristic (ROC), or simply ROC curve, is a graphical plot of the sensitivity, or true positives, vs. (1 − specificity), or false positives, for a binary classifier system as its discrimination threshold is varied. The ROC can also be represented equivalently by plotting the fraction of true positives (TPR = true positive rate) vs. the fraction of false positives (FPR = false positive rate).
A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.
The phenomenon where the expectations of the researchers in a study influence the outcome.
A period before randomization when participants are monitored but receive no treatment (or they sometimes all receive one of the study treatments, possibly in a blind fashion). The data from this stage of a trial are only occasionally of value but can serve a valuable role in screening out ineligible or non-compliant participants, in ensuring that participants are in a stable condition, and in providing baseline observations. A run-in period is sometimes called a washout period if treatments that participants were using before entering the trial are discontinued.
The status of health in rural populations.
Health services, public or private, in rural areas. The services include the promotion of health and the delivery of health care.
The status of health in rural populations.
The inhabitants of rural areas or of small towns classified as rural. Table of contents:
Sexual behavior that prevents or reduces the spread of sexually transmitted diseases or pregnancy.
Safety is the state of being "safe" (from French sauf), the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be considered non-desirable.
Freedom from exposure to danger and protection from the occurrence or risk of injury or loss. It suggests optimal precautions in the workplace, on the street, in the home, etc., and includes personal safety as well as the safety of property.
The safety of a medical product concerns the medical risk to the subject, usually assessed in a clinical trial by laboratory tests (including clinical chemistry and hematology), vital signs, clinical adverse events (diseases, signs and symptoms), and other special safety tests (e.g. ECGs, ophthalmology). The tolerability of the medical product represents the degree to which overt adverse effects can be tolerated by the subject.
The development of systems to prevent accidents, injuries, and other adverse occurrences in an institutional setting. The concept includes prevention or reduction of adverse events or incidents involving employees, patients, or facilities. Examples include plans to reduce injuries from falls or plans for fire safety to promote a safe institutional environment.
Safety monitoring of a clinical trial is conducted by an independent physician with relevant expertise. This is accomplished by review of adverse event, immediately after they occur, with timely follow-up through resolution.
Refers to serious adverse effects, such as those that threaten life, require or prolong hospitalization, result in permanent disability, or cause birth defects. Indirect adverse effects, such as traffic accidents, violence, and damaging consequences of mood change, can also be serious.
A subset selected for the study from the larger population.
A selected subset of a population. A sample may be random or non-random and it may be representative or non-representative.
The sample size of a statistical sample is the number of observations that constitute it. It is typically denoted n, a positive integer (natural number).
The number of participants in the trial. The intended sample size is the number of participants planned to be included in the trial, usually determined using a statistical power calculation. The sample size should be adequate to provide a high probability of detecting as significant an effect size of a given magnitude if such an effect actually exists. The achieved sample size is the number of participants enrolled, treated or analyzed in the study.
The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups.
In statistics sampling bias is causing some members of the population to be less likely to be included than others. It results in a biased sample, a non-random sample of a population (or non-human factors) in which all participants are not equally balanced or objectively represented. If the bias makes estimation of population parameters impossible, the sample is a non-probability sample. If this is not accounted for, results can be erroneously attributed to the phenomenon under study rather than to the method of sampling It is a form of sampling error, that is, an error caused by observing a sample instead of the whole population. However, sampling error also includes non-systematic errors that can be decreased by increasing sample size. It is also called ascertainment bias. Ascertainment bias has basically the same definition, but is still sometimes classified as a separate type of bias.
Method by which households to be sampled are selected within the target population.
The discrepancy between the values obtained from the relatively small sample and the larger population from which the sample was drawn.
List of households, or sub-sections of the study area/population, used to allocate clusters or select households to be sampled.
Studies in which a number of subjects are selected from all subjects in a defined population. Conclusions based on sample results may be attributed only to the population sampled.
Provides the raison d'étre for economics because if there were no scarcity then there would be no need to make difficult resource allocation decisions. Scarcity is a relative concept. Resources may be plentiful in absolute terms but appear scarce when our ability to promote health exceeds our resource capacity to do so. That is, scarcity exists when the claims on resources (that is, wants or needs) outstrip the resources available.
A graph displaying the scatter of the relationship between two variables. The scatter diagram gives an indication of whether a correlation may exist and its direction.
A graph in which each dot represents paired values for two continuous variables, with the x-axis representing one variable and the y-axis representing the other; used to display the relationship between the two variables; also called a scattergram.
An account or synopsis of a possible course of events that could occur, which forms the basis for planning assumptions (for example, a river floods, covering a nearby town and wiping out the local population's crop). Scenario-building is process of developing hypothetical scenarios in the context of a contingency planning exercise.
Scientific misconduct is the violation of the standard codes of scholarly conduct and ethical behavior in professional scientific research.
A class of ethical violations in the conduct of research, generally taken to include falsification, fabrication, fraud, or plagiarism in the proposal, design, implementation, reporting, or review of research, but may also be taken to include violation of the rights and dignity of participants in research, misuse of research funds, and mistreatment of scientific colleagues.
Intentional falsification of scientific data by presentation of fraudulent or incomplete or uncorroborated findings as scientific fact.
Screening, in medicine, is a strategy used in a population to detect a disease in individuals without signs or symptoms of that disease.
Refers to trials which test the best way to detect certain diseases or health conditions.
It is related to the language bias. It is the systematic error introduced when the search of studies is centered in just one database (for example, Medline). Journals written in English are overrepresented in Medline; furthermore, the journals from the country (and from neighboring countries or either countries of similar language or culture) where the database is done are also represented in excess. It is recommended to consult more than one database (for example, Medline and Embase), supplemented by a hand search of the references of each publication collected.
In statistics, many time series exhibit cyclic variation known as seasonality, periodic variation, or periodic fluctuations. This variation can be either regular or semiregular.
Change in physiological status or in disease occurrence that conforms to a regular seasonal pattern.
The middle third of a human pregnancy, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.
A measure of the frequency of new cases of a disease among the contacts of known cases.
Medical care provided to a patient when referred by one health professional to another with more specialized qualifications or interests. There are two levels of referred care: secondary and tertiary. Secondary care is usually provided by a broadly skilled specialist such as a general surgeon, general internist or obstetrician.
Specialized ambulatory medical services and commonplace hospital care (outpatient and inpatient services). Access is often via referral from primary health care services.
Also called secondary health care.
Secondary data is data collected by someone other than the user. Common sources of secondary data for social science include censuses, surveys, organizational records and data collected through qualitative methodologies or qualitative research.
Percentage of women with no births and no pregnancies in the past five years but who have had a birth or pregnancy at some time, among women who have been married for the past five years but did not use contraception during that period.
Secondary infertility means that the couple has previously conceived, but is subsequently unable to conceive despite regular unprotected intercourse for a period of 12 months (medical definition). If the woman has breastfed a previous infant, then exposure to pregnancy is calculated from the end of lactational amenorrhea.
Percentage of women with no births in the past five years but who have had a birth at some time, among women who have been married for the past five years and did not use contraception during that period (demographic definition).
An outcome used to evaluate additional effects of the intervention deemed a priori as being less important than the primary outcomes.
Interruption of the chain of causality at a point where physiological or psychological abnormality is present but before there is manifestation as a symptom or sign noticed by the individual.
The prevention of recurrences or exacerbations of a disease that already has been diagnosed. This also includes prevention of complications or after-effects of a drug or surgical procedure.
Synthesis (summary) of primary level research (trials, studies), in the form of reviews, systematic reviews or meta-analyses.
Research that does not generate primary data but that involves the qualitative or quantitative synthesis of information from multiple primary studies. Examples are literature reviews, meta-analyses, decision analyses and consensus statements.
Aldo called secondary level research.
Secondary sources are reports that quote other people’s studies; these may be reviews.
A study of studies: a review of individual studies (each of which is called a primary study). A systematic review is a secondary study.
Changes in the probability of events with time, independent of known predictors of outcome.
Changes over a long period of time, generally years or decades.
An error in choosing the individuals or groups to take part in a study. Ideally, the subjects in a study should be very similar to one another and to the larger population from which they are drawn (for example, all individuals with the same disease or condition). If there are important differences, the results of the study may not be valid.
Systematic differences between comparison groups in prognosis or responsiveness to treatment. Random allocation with adequate concealment of allocation protects against selection bias. Other means of selecting who receives the intervention are more prone to bias because decisions may be related to prognosis or responsiveness to treatment.
A systematic error in reviews due to how studies are selected for inclusion. Reporting bias is an example of this.
A systematic difference in characteristics between those who are selected for study and those who are not. This affects external validity but not internal validity.
The introduction of error due to systematic differences in the characteristics between those selected and those not selected for a given study. In sampling bias, error is the result of failure to ensure that all members of the reference population have a known chance of selection in the sample.
Selective prevention strategies target subsets of the total population that are deemed to be at risk for substance abuse by virtue of their membership in a particular population segment, e.g. children of adult alcoholics, dropouts, or students who are failing academically.
Services to be offered to asymptomatic persons with one or more risk factors for a target condition, such as family history of the disease, certain personal behaviors, or membership in a population with increased prevalence of the disease.
Perceived self-efficacy refers to beliefs that individuals hold about their capability to carry out action in a way that will influence the events that affect their lives.
Percentage of women who report having had a hysterectomy, or say they have gone through menopause, or report not having had a menstrual period in the past five years, or have never had a menstrual period.
In screening/diagnostic tests: a measure of a test’s ability to correctly detect people with the disease. It is the proportion of diseased cases that are correctly identified by the test. It is calculated as follows: Sensitivity = Number with disease who have a positive test/Number with disease. (Also called true positive rate, detection rate.)
In trial searching: a measure of a search’s ability to correctly identify relevant articles. It is the proportion of all relevant articles from all searches that were identified by the particular search of interest. It is calculated as follows: Sensitivity = Number of relevant articles identified by the search/Total number of relevant articles from all searches. (Also called recall.)
The ability of a system to detect epidemics and other changes in disease occurrence. The proportion of persons with disease who are correctly identified by a screening test or case definition as having disease.
An analysis used to determine how sensitive the results of a study or systematic review are to changes in how it was done. Sensitivity analyses are used to assess how robust the results are to uncertain decisions or assumptions about the data and the methods that were used.
There are different ways of sensitivity analysis. In the assessment of heterogeneity it is concerned with the effects of inclusion and exclusion of specific studies. In the use of statistical procedures, sensitivity analysis is the repetition of the analysis using different statistical methods of pooling to assess whether the same results are achieved, and whether the quality of the individual studies and publication bias change the pooled estimates.
Describes the process of assessing the robustness of an economic evaluation by considering the effects of uncertainty. All evaluations are characterized by some degree of uncertainty or ignorance about the future course of events. In a sensitivity analysis, the results of the evaluation are re-worked after systematically substituting high and low values for each of the variables of interest (the discount rate or the expected loss to follow up, for example). If the conclusions remain unchanged after the re-analysis, then the results can be said to be robust. If the results are not robust, then sensitivity analysis can show where better information will be most useful.
Sensitivity and specificity are statistical measures of the performance of a binary classification test. Sensitivity (also called recall rate in some fields) measures the proportion of actual positives which are correctly identified as such (e.g. the percentage of sick people who are identified as having the condition). Specificity measures the proportion of negatives which are correctly identified (e.g. the percentage of healthy people who are identified as not having the condition).
Measures for assessing the results of diagnostic and screening tests. Sensitivity represents the proportion of truly diseased persons in a screened population who are identified as being diseased by the test. It is a measure of the probability of correctly diagnosing a condition. Specificity is the proportion of truly nondiseased persons who are so identified by the screening test. It is a measure of the probability of correctly identifying a nondiseased person.
The ability of a surveillance or reporting system to detect true health events, i.e. the ratio of the total number of health events detected by the system to the total number of true health events as determined by an independent and more complete means of ascertainment.
Ability of the case definition to detect all cases of the disease targeted for surveillance.
Ability of the surveillance system to detect cases, i.e. proportion of cases notified divided by the total number of cases meeting the case definition.
Ability of the surveillance system to detect outbreaks.
The tendency for human performance to improve when participants are aware that their behavior is being evaluated; in contrast to the Hawthorne effect, which refers to behavior change as a result of being observed but not evaluated.
A surveillance system in which a pre-arranged sample of reporting sources agrees to report all cases of one or more notifiable conditions.
Monitoring of rate of occurrence of specific conditions to assess the stability or change in health levels of a population. It is also the study of disease rates in a specific cohort, geographic area, population subgroup, etc. to estimate trends in larger population.
A sample in which all potentially eligible patients seen over a period of time are enrolled.
A randomized trial in which the data are analyzed after each participant’s results become available, and the trial continues until a clear benefit is seen in favor of one of the comparison groups, or it is unlikely that any difference will emerge. The main advantage of sequential trials is that they are usually shorter than fixed size trials when there is a large difference in the effectiveness of the interventions being compared. Their use is restricted to conditions where the outcome of interest is known relatively quickly. In a group sequential trial, a limited number of interim analyses of the data are carried out at pre-specified times during recruitment and follow up, say 3-6 times in all.
Any untoward medical occurrence that at any dose: results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, or is a congenital anomaly/birth defect.
Epidemiologic studies based on the detection through serological testing of characteristic change in the serum level of specific antibodies. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.
The social and physical environment where the intervention is being implemented.
Levels of severity of illness within a diagnostic group which are established by various measurement criteria.
Sex refers to the biological characteristics that define humans as female or male. While these sets of biological characteristics are not mutually exclusive, as there are individuals who possess both, they tend to differentiate humans as males and females. In general use in many languages, the term sex is often used to mean “sexual activity”, but for technical purposes in the context of sexuality and sexual health discussions, the above definition is preferred.
The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism.
Those characteristics that distinguish one sex from the other. the primary sex characteristics are the ovaries and testes and their related hormones. secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.
Advice and support given to individuals to help them understand and resolve their sexual adjustment problems. it excludes treatment for psychosexual disorders or psychosexual dysfunction.
The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.
Education which increases the knowledge of the functional, structural, and behavioral aspects of human reproduction.
Maleness or femaleness as a constituent element or influence contributing to the production of a result. it may be applicable to the cause or effect of a circumstance. it is used with human or animal concepts but should be differentiated from sex characteristics, anatomical or physiological manifestations of sex, and from sex distribution, the number of males and females in given circumstances.
The number of males per 100 females in a population.
The ratio of males to females in a population.
A mortality rate among either males or females.
The scientific study of sexual interests, behavior, and function.
This discipline concerns the study of sexuality, and the application of sexual knowledge such as sexual attitudes, psychology, and sexual behavior. Scope of application generally includes educational (sex education), clinical (sex counseling), and other settings.
Refraining from sexual intercourse.
Sexual abuse, also referred to as molestation, is the forcing of undesired sexual behavior by one person upon another, when that force is immediate, short duration, or infrequent, it is called sexual assault.
Any violation of established legal or moral codes in respect to sexual behavior.
Also called sex offense.
Human sexual activities or human sexual practices or human sexual behavior refers to the manner in which humans experience and express their sexuality.
Sexual activities of humans.
The processes of anatomical and physiological changes related to sexual or reproductive functions during the life span of a human or an animal, from fertilization to death. These processes include sex differentiation; sexual maturation; and changes during aging.
Sexual health is a state of physical, emotional, mental and social well-being in relation to sexuality; it is not merely the absence of disease, dysfunction or infirmity. Sexual health requires a positive and respectful approach to sexuality and sexual relationships, as well as the possibility of having pleasurable and safe sexual experiences, free of coercion, discrimination and violence. For sexual health to be attained and maintained, the sexual rights of all persons must be respected, protected and fulfilled.
Achievement of full sexual capacity in animals and in humans.
Sexual partners are people who engage in consensual sexual activity together. The sexual partners can be of any gender or sexual orientation. The sexual partners may be in a committed relationship, either on an exclusive basis or not, or engage in the sexual activity on a casual basis.
Married or single individuals who share sexual relations.
Sexual rights embrace human rights that are already recognized in national laws, international human rights documents and other consensus statements. They include the right of all persons, free of coercion, discrimination and violence, to: • the highest attainable standard of sexual health, including access to sexual and reproductive health care services; • seek, receive and impart information related to sexuality; • sexuality education; • respect for bodily integrity; • choose their partner; • decide to be sexually active or not; • consensual sexual relations; • consensual marriage; • decide whether or not, and when, to have children; and • pursue a satisfying, safe and pleasurable sexual life. The responsible exercise of human rights requires that all persons respect the rights of others.
Human sexuality is how people experience the erotic and express themselves as sexual beings.
Sexuality is a central aspect of being human throughout life and encompasses sex, gender identities and roles, sexual orientation, eroticism, pleasure, intimacy and reproduction. Sexuality is experienced and expressed in thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles and relationships. While sexuality can include all of these dimensions, not all of them are always experienced or expressed. Sexuality is influenced by the interaction of biological, psychological, social, economic, political, cultural, ethical, legal, historical, religious and spiritual factors.
The sexual functions, activities, attitudes, and orientations of an individual. Sexuality, male or female, becomes evident at puberty under the influence of gonadal steroids (testosterone or estradiol), and social effects.
A sexually transmitted disease (STD), also known as sexually transmitted infection (STI) or venereal disease (VD), is an illness that has a significant probability of transmission between humans or animals by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex.
Diseases due to or propagated by sexual contact.
An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial. Also called placebo therapy.
A problem that occurs when treatment affects healthy tissues or organs.
Any undesired actions or effects of a drug or treatment. Negative or adverse effects may include headache, nausea, hair loss, skin irritation, or other physical problems. Experimental drugs must be evaluated for both immediate and long-term side effects.
Any unintended effect of an intervention. Side effects are most commonly associated with pharmaceutical products, in which case they are related to the pharmacological properties of the drug at doses normally used for therapeutic purposes in humans
In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.
In statistics, a simple random sample is a subset of individuals (a sample) chosen from a larger set (a population). Each individual is chosen randomly and entirely by chance, such that each individual has the same probability of being chosen at any stage during the sampling process, and each subset of k individuals has the same probability of being chosen for the sample as any other subset of k individuals.
A simple random sample (or single stage random) is an example of a probability sample. It is the ideal sampling frame for a survey because each eligible individual in the population has a known and non-zero chance of being included in the sample. However, this sampling frame is very expensive and often not logistically feasible. As a result, most surveys employ some form of cluster sampling.
Sampling design whereby an individual sampling frame of households is established, and households to be sampled are selected using random numbers.
Randomization without restriction. In a two-group trial, it is analogous to the toss of a coin.
Regression when there is only one independent variable under evaluation with respect to a dependent variable.
A type of clinical trial in which only the doctor knows whether a patient is taking the standard treatment or the new treatment being tested. This helps prevent bias in treatment studies.
A study in which one party, either the investigator or participant, is unaware of what medication the participant is taking; also called single-masked study.
A method in which either the observer(s) or the subject(s) is kept ignorant of the group to which the subjects are assigned.
The unmarried man or woman.
Study of a situation which may require improvement. This begins with a definition of the problem and an assessment or measurement of its extent, severity, causes, and impacts upon the community, and is followed by appraisal of interaction between the system and its environment and evaluations of performance.
A frequency distribution curve which is asymmetrical, with one side of the curve extending in an elongated fashion.
A skilled birth attendant is an accredited health professional—such as a midwife, doctor or nurse—who has been educated and trained to proficiency in the skills needed to manage normal (uncomplicated) pregnancies, childbirth and the immediate postnatal period, and in the identification, management and referral of complications in women and newborns. Traditional birth attendants, trained or not, are excluded from the category of skilled attendant at delivery.
A method of analyzing the variation in utilization of health care in small geographic or demographic areas. It often studies, for example, the usage rates for a given service or procedure in several small areas, documenting the variation among the areas. By comparing high- and low-use areas, the analysis attempts to determine whether there is a pattern to such use and to identify variables that are associated with and contribute to the variation.
Birth weight less than 2 standard deviations below the mean or less than the 10th centile according to local intrauterine growth charts.
Small for gestational age (SGA) babies are those whose birth weight, length, or head circumference lies below the 10th percentile for that gestational age.
An infant having a birth weight lower than expected for its gestational age.
When a test with a high Sensitivity is Negative, it effectively rules out the diagnosis of disease.
Study participants nominate or refer other potential study participants who meet the study inclusion criteria.
Services related to long-term inpatient care plus community care services, such as day care centers and social services for the chronically ill, the elderly and other groups with special needs such as the mentally ill, mentally handicapped and the physically handicapped.
Social classes are the hierarchical arrangements of people in society as economic or cultural groups.
A stratum of people with similar position and prestige; includes social stratification. Social class is measured by criteria such as education, occupation, and income.
The branch of epidemiology that studies the social distribution and social determinants of health.
Social marketing is the application of commercial marketing technologies to the analysis, planning, execution and evaluation of programs designed to influence the behavior of target audiences in order to improve the welfare of individuals and society.
Use of marketing principles also used to sell products to consumers to promote ideas, attitudes and behaviors. Design and use of programs seeking to increase the acceptance of a social idea or practice by target groups, not for the benefit of the marketer, but to benefit the target audience and the general society.
A branch of medicine concerned with the role of socio-environmental factors in the occurrence, prevention and treatment of disease.
The provision of social protection against a number of risks, such as incapacity to work resulting from disease or disability, unemployment, old age, or family maintenance.
Government sponsored social insurance programs.
Social work is a professional and academic discipline committed to the pursuit of social welfare and social change.
The use of community resources, individual case work, or group work to promote the adaptive capacities of individuals in relation to their social and economic environments. It includes social service agencies.
Social and economic factors that characterize the individual or group within the social structure.
Refers to the worse health of those who are at a lower level of socioeconomic position—whether measured by income, occupational grade, or educational attainment—even those who are already in relatively high socioeconomic groups.
All information in original records and certified copies of original records of clinical findings, observations, or other activities in a clinical trial necessary for the reconstruction and evaluation of the trial. Source data are contained in source documents (original records or certified copies).
Original documents, data, and records (e.g., hospital records, clinical and office charts, laboratory notes, memoranda, subjects' diaries or evaluation checklists, pharmacy dispensing records, recorded data from automated instruments, copies or transcriptions certified after verification as being accurate and complete, microfiches, photographic negatives, microfilm or magnetic media, x-rays, subject files, and records kept at the pharmacy, at the laboratories, and at medico-technical departments involved in the clinical trial).
A statistically significant excess of cases of a disease, occurring within a limited space-time continuum.
Approach to selection of clusters or households to be sampled, whereby clusters and/or households are allocated proportionately to surface area within the study area. Alternative to population-proportional sampling.
Ratio between the number of live births born to mothers 15 to 19 years of age during a given year and the mid-year female population 15 to 19 years of age, for a given country, territory, or geographic area, during a specified period, usually multiplied by 1,000.
Intermediate result necessary to achieve the general objective. Specific objectives always relate to changes in the target groups so that the outcomes are clearly measurable. The specific objectives need not necessarily relate to drug use but each of them, if achieved, should lead plausibly to fulfillment of the general objective. The measurement of specific objectives through outcome indicators lead to an outcome evaluation.
The population in which the change defined as a general objective is to be reached.
A methodological technique for interpreting a more general ethical principle to bring its implications closer to—to better “apply” it to—actions and decisions. Specification may be used to resolve conflicts among, to balance, or to rank principles. In public health, the precautionary principle is a specified version of the more general principle of beneficence.
In screening/diagnostic tests: a measure of a test’s ability to correctly identify people who do not have the disease. It is the proportion of people without the target disease who are correctly identified by the test. It is the complement of the false positive rate (FPR=1-specificity). It is calculated as follows: Specificity = Number without disease who have a negative test/Number without disease.
The proportion of persons without disease who are correctly identified by a screening test or case definition as not having disease.
Specificity is established when a single putative cause produces a specific effect.
A measure of how infrequently a system detects false positive health events, i.e. the number of individuals identified by the system as not being diseased divided by the total number of all persons who do not have the disease.
Ideally, diagnostic test properties will be assessed in a population in which the spectrum of disease in the target-positive patients includes all those in whom clinicians might be uncertain about the diagnosis, and the target-negative patients include all those with conditions easily confused with the target condition. Spectrum bias may occur when the accuracy of a diagnostic test is assessed in a population that differs from this ideal. Examples of spectrum bias include a situation in which a substantial proportion of the target-positive population have advanced disease, and target-negative participants are normal or asymptomatic. Such situations typically occur in diagnostic case-control studies (e.g., comparing those with advanced disease to normal individuals). Such studies are liable to yield an overly sanguine estimate of the usefulness of the test.
An individual, company, institution, or organization that takes responsibility for the initiation, management, and/or financing of a clinical trial.
A person who initiates a clinical investigation, but who does not actually conduct the investigation, i.e., the test article is administered or dispensed to or used involving, a subject under the immediate direction of another individual. A person other than an individual (e.g., corporation or agency) that uses one or more of its own employees to conduct a clinical investigation it has initiated is considered to be a sponsor (not a sponsor-investigator), and the employees are considered to be investigators.
An individual who both initiates and conducts, alone or with others, a clinical trial, and under whose immediate direction the investigational product is administered to, dispensed to, or used by a subject. The term does not include any person other than an individual (e.g., it does not include a corporation or an agency). The obligations of a sponsor-investigator include both those of a sponsor and those of an investigator.
An individual who both initiates and actually conducts, alone or with others, a clinical investigation, i.e., under whose immediate direction the test article is administered or dispensed to, or used involving, a subject. The term does not include any person other than an individual, e.g., corporation or agency.
A disease that occurs infrequently and irregularly.
A map that indicates the location of each case of a rare disease or outbreak by a place that is potentially relevant to the health event being investigated, such as where each case lived or worked.
When a test is highly Specific, a Positive result can rule in the diagnosis.
Groups that have an interest in the organization and delivery of health care, and who either conduct, sponsor, or are consumers of health care research, such as patients, payers, health care practitioners.
Stakeholders are people involved in or affected by proposal development and implementation, drawn from public, private and voluntary sectors, and the communities or groups affected.
A measure of the spread or dispersion of a set of observations, calculated as the average difference from the mean value in the sample.
The standard deviation of the sampling distribution of a statistic. Measurements taken from a sample of the population will vary from sample to sample. The standard error is a measure of the variation in the sample statistic over all possible samples of the same size. The standard error decreases as the sample size increases. (Also called SE.)
A method of establishing the utility of a specified health state. For chronic health states, people are asked to choose between the certainty of the specified health state for a given period of time or a gamble that involves a probability (p) of restoration to full health and a complementary probability (1−p) of immediate death. The value of p is changed until the respondent regards the two options as equivalent to each other. The utility of the specified health state is then given by p. A slightly modified method is needed for temporary health states or states regarded as worse than death.
Detailed, written instructions to achieve uniformity of the performance of a specific function.
A treatment currently in wide use and approved by the FDA, considered to be effective in the treatment of a specific disease or condition.
Instruments of examination, observation‚ or evaluation that share a standard set of instructions for their administration, use, scoring, and interpretation.
The difference between two estimated means divided by an estimate of the standard deviation. It is used to combine results from studies using different ways of measuring the same concept, e.g. mental health. By expressing the effects as a standardized value, the results can be combined since they have no units. Standardized mean differences are sometimes referred to as a d index. (Also called SMD.)
The number of deaths in a given year as a percentage of those expected (expected = standard mortality of the reference period, adjusted for age and sex).
Standardized rates are a statistical measure of any rates in a population. The most common are birth, death and unemployment rates. The formula for standardized rates is as follows: ∑(crude rate for age group ∑ standard population for age group) / ∑standard population
Treatment regimen or medical management based on state of the art participant care.
The state of the art is the highest level of development, as of a device, technique, or scientific field, achieved at a particular time. It also applies to the level of development (as of a device, procedure, process, technique, or science) reached at any particular time usually as a result of modern methods.
A statistical analysis plan is a document that contains a more technical and detailed elaboration of the principal features of the analysis described in the protocol, and includes detailed procedures for executing the statistical analysis of the primary and secondary variables and other data.
Factor analysis is a statistical method used to describe variability among observed variables in terms of a potentially lower number of unobserved variables called factors. In other words, it is possible, for example, that variations in three or four observed variables mainly reflect the variations in a single unobserved variable, or in a reduced number of unobserved variables.
A set of statistical methods for analyzing the correlations among several variables in order to estimate the number of fundamental dimensions that underlie the observed data and to describe and measure those dimensions. It is used frequently in the development of scoring systems for rating scales and questionnaires.
Statistical methodologies to make deductions about underlying truth. There are two principle functions: (1) To predict or estimate a population parameter from a sample statistic, and (2) to test statistically based hypotheses.
The development of generalizations from sample data, usually with calculated degrees of uncertainty.
The probability that an event or difference occurred by chance alone. In clinical trials, the level of statistical significance depends on the number of participants studied and the observations made, as well as the magnitude of differences observed.
A statistic indicating that the result obtained is probably not due to chance but is real. A statistically significant result does not necessarily mean that it is important or interesting.
A test to estimate the likelihood that an observed study result, for example a difference between two groups or an association, can be due to chance.
A result that is unlikely to have happened by chance. The usual threshold for this judgment is that the results, or more extreme results, would occur by chance with a probability of less than 0.05 if the null hypothesis was true. Statistical tests produce a p-value used to assess this.
The science of making effective use of numerical data relating to groups of individuals or experiments.
The science and art of collecting, summarizing, and analyzing data that are subject to random variation. The term is also applied to the data themselves and to the summarization of the data.
Statistics [MeSH - publication type]: works consisting of presentations of numerical data on particular subjects.
The event that a fetus is born dead or stillborn.
In probability theory, a stochastic process, or sometimes random process, is the counterpart to a deterministic process (or deterministic system).
Processes that incorporate some element of randomness, used particularly to refer to a time series of random variables.
Truncated randomized controlled trials (RCTs) are trials stopped early because of apparent harm because the investigators have concluded that they will not be able to demonstrate a treatment effect (futility), or because of apparent benefit. Believing the treatment from RCTs stopped early for benefit will be misleading if the decision to stop the trial resulted from catching the apparent benefit of treatment at a random high.
A procedure that allows interim analyses in clinical trials at predefined times, whilst preserving the Type I error at some pre-specified level.
In some trials, a statistical criterion that, when met by the accumulating data, indicates that the trial can or should be stopped early to avoid putting participants at risk unnecessarily or because the intervention effect is so great that further data collection is unnecessary. Usually defined in the trial protocol and implemented during a planned interim analysis.
The process by which groups are separated into mutually exclusive sub-groups of the population that share a characteristic: e.g. age group, sex, or socioeconomic status. It is possible to compare these different strata to try and see if the effects of a treatment differ between the sub-groups.
Sampling and analysis of sub-groups or sub-periods.
A sampling procedure in which the researcher tries to ensure that important subgroups in the population are adequately represented.
A method used to ensure that equal numbers of participants with a characteristic thought to affect prognosis or response to the intervention will be allocated to each comparison group. For example, in a trial of women with breast cancer, it may be important to have similar numbers of pre-menopausal and post-menopausal women in each comparison group. Stratified randomization could be used to allocate equal numbers of pre- and post-menopausal women to each treatment group. Stratified randomization is performed by performing separate randomization (often using random permuted blocks) for each strata.
In statistics, stratified sampling is a method of sampling from a population.
A stratified sampling technique is the process by which the population is divided into subgroups. Sampling will then be conducted in each subgroup. Subgroups are chosen because evidence is available that they are related to an outcome of interest (i.e. population coverage, health status, ethnicity, etc). The strata chosen will vary by survey or country to reflect local needs.
Strength of evidence is often assessed on a combination of the study design (level of evidence), study quality (how well it was implemented), and statistical precision (p value and confidence intervals).
The likelihood that an observed difference between groups within a study represents a real difference rather than mere chance or the influence of confounding factors, based on both p values and confidence intervals. Strength of inference is weakened by various forms of bias and by small sample sizes.
Strength of the association is defined by the magnitude and statistical significance of the measured risk.
Aspects of the design of health services that influence the way in which services are delivered. These include the numbers and types of personnel and staff; the way in which these personnel are organized to do their work; the nature and extent of the facility and equipment; the range of services offered; systems of management and amenities; accessibility; mode of financing; the way in which the eligible population is determined and enumerated; and the mechanisms of governance and administrative decision making.
These abstracts often include critical information about research conduct omitted from the original reports. They do not include the introduction or the discussion sections of the original report or the conclusions of the original study.
An interview in which the questions are generally pre-defined, asked in a fixed order and recorded in writing.
A primary or secondary outcome used to judge the effectiveness of a treatment.
The primary investigative techniques used in an observational protocol; types are Purpose, Duration, Selection, and Timing.
Study validity refers to the degree to which the inferences drawn from a study are warranted when account is taken of the study methods; the representativeness of the study sample; and the nature of the population from which it is drawn.
An analysis in which the intervention effect is evaluated in a defined subset of the participants in a trial, or in complementary subsets, such as by sex or in age categories. Trial sizes are generally too small for sub-group analyses to have adequate statistical power. Comparison of sub-groups should be by test of interaction rather than by comparison of p-values. Sub-group analyses are also subject to the multiple comparisons problem.
Any individual member of the clinical trial team designated and supervised by the investigator at a trial site to perform critical trial-related procedures and/or to make important trial-related decisions (e.g., associates, residents, research fellows).
A unique identifier assigned by the investigator to each trial subject to protect the subject's identity and used in lieu of the subject's name when the investigator reports adverse events and/or other trial-related data.
Measures involving a substantial degree of human interpretation, for example ratings of pain.
Participants in a study. They should not be called material for the study.
The inhabitants of peripheral or adjacent areas of a city or town.
A causal factor or collection of factors whose presence is always followed by the occurrence of the effect (of disease).
Summative evaluation is a method of judging the worth of a program at the end of the program activities. The focus is on the outcome.
A trial with the primary objective of showing that the response to the investigational product is superior to a comparative agent (active or placebo control).
The person who is responsible for guiding the individual(s) doing a research project.
A phenomenon whereby a health care provider, usually a physician, influences the level of a person’s demand for health care services.
In clinical trials, a surrogate endpoint (or marker) is a measure of effect of a certain treatment that may correlate with a real clinical endpoint but doesn't necessarily have a guaranteed relationship.
Outcome measures that are not of direct practical importance but are believed to reflect outcomes that are important; for example, blood pressure is not directly important to patients but it is often used as an outcome in clinical trials because it is a risk factor for stroke and heart attacks. Surrogate endpoints are often physiological or biochemical markers that can be relatively quickly and easily measured, and that are taken as being predictive of important clinical outcomes. They are often used when observation of clinical outcomes requires long follow-up. (Also called intermediary outcomes, surrogate outcomes.)
A variable that provides an indirect measurement of effect in situations where direct measurement of clinical effect is not feasible or practical.
Continuous analysis, interpretation and feedback of systematically collected data, generally using methods distinguished by their practicality, uniformity, and rapidity rather than by accuracy or completeness. By observing trends in time, place and persons, changes can be observed or anticipated and appropriate action including investigative or control measures, can be taken. Sources of data may relate directly to disease or to factors influencing disease.
Observational study that focuses on obtaining information about activities, beliefs, preferences, knowledge, or attitudes from respondents through interviewer-administered or self-administered methods.
The process of collecting information by canvassing a chosen group.
Continuance of life or existence especially under adverse conditions; includes methods and philosophy of survival.
The analysis of data that measure the time to an event e.g. death, next episode of disease.
A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.
Type of selection bias specific to retrospective surveys, whereby households that disappear during the recall period because of the death of all members and consequent disintegration are not represented in the sample. It occurs when high and/or very clustered mortality persists for a long period. Survival bias always results in an under-estimation of mortality.
A curve that starts at 100% of the study population and shows the percentage of the population still surviving at successive times for as long as information is available. May be applied not only to survival as such, but also to the persistence of freedom from a disease, or complication or some other endpoint.
The proportion of persons in a specified group (age, sex, or health status) alive at the beginning of an interval (such as a five-year period) who survive to the end of the interval.
The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.
Sustainable health promotion actions are those that can maintain their benefits for communities and populations beyond their initial stage of implementation. Sustainable actions can continue to be delivered within the limits of finances, expertise, infrastructure, natural resources and participation by stakeholders.
The capacity to meet the needs of the present without compromising the ability to meet future needs.
Systematic errors are biases in measurement which lead to the situation where the mean of many separate measurements differs significantly from the actual value of the measured attribute.
A systematic error or bias occurs when there is a difference between the true value (in the population) and the observed value (in the study) from any cause other than sampling variability.
A review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyze and summaries the results of the included studies.
A systematic review is a method of identifying, appraising, and synthesizing research evidence. The aim is to evaluate and interpret all available research that is relevant to a particular review question. A systematic review differs from a traditional literature review in that the latter describes and appraises previous work, but does not specify methods by which the reviewed studies were identified, selected, or evaluated. In a systematic review, the scope (for example, the review question and any sub-questions and/or sub-group analyses) is defined in advance, and the methods to be used at each step are specified. The steps include: a comprehensive search to find all relevant studies; the use of criteria to include or exclude studies; and the application of established standards to appraise study quality. A systematic review also makes explicit the methods of extracting and synthesizing study findings.
A synthesis of the results of several primary studies by using procedures that limit bias and random error. These procedures include a search of all potentially relevant investigations and the use of explicit and reliable criteria in the selection of investigations for review. A qualitative systematic review summarizes the primary investigations without statistical pooling. Quantitative systematic review is synonymous with meta-analysis.
Sampling design whereby an individual sampling frame of households is established, and households to be sampled are selected using a constant sampling step.
A sampling procedure in which subjects are selected by a simple periodic process, for example, selecting every second or third patient.
Systematic sampling incorporates a systematic method to a random sample (for example, the randomly selected number is five, therefore every fifth household would be sampled on selected streets). Table of contents:
A statistical distribution describing the distribution of the means of samples taken from a population with unknown variance.
A statistical hypothesis test derived from the t distribution. It is used to compare continuous data in two groups. (Also called Student’s t-test.)
A statistical test that is used to find out if there is a real difference between the means (averages) of two different groups. It is sometimes used to see if there is a significant difference in response to treatment between groups in a clinical trial.
In diagnostic test studies, the condition the investigators or clinicians are particularly interested in identifying (e.g., tuberculosis, lung cancer, or iron-deficiency anemia).
In intervention studies, the condition the investigators or clinicians are particularly interested in identifying and in which it is anticipated the intervention will decrease (e.g., myocardial infarction, stroke, or death) or increase (e.g., ulcer healing).
In diagnostic test studies, patients who do not have the target condition.
In diagnostic test studies, patients who do have the target condition.
With technical efficiency, an objective such as the provision of tonsillectomy for children in need of this procedure is taken as given. Technical efficiency is about how best to achieve that objective. Strictly, technical efficiency is about ensuring the production of the same level of output with less of one input and no more of other inputs or, equivalently, maximizing the output that one gets from given quantities of inputs. Technical efficiency is linked to cost effectiveness. The combination of technically efficient inputs that minimizes the cost of achieving a given level of output is that which is cost effective.
A technical report (also: scientific report) is a document that describes the process, progress, or results of technical or scientific research or the state of a technical or scientific research problem.
Technical report [MeSH - publication type]: work consisting of a formal report giving details of the investigation and results of a medical or other scientific problem. When issued by a government agency or comparable official body, its contents may be classified, unclassified, or declassified with regard to security clearance. This publication type may also cover a scientific paper or article that records the current state or current position of scientific research and development. If so labeled by the editor or publisher, this publication type may be properly used for journal articles.
A multi-disciplinary field of policy analysis that examines the medical, economic, social and ethical implications of the incremental value, diffusion and use of a medical technology in health care.
Evaluation of biomedical technology in relation to cost, efficacy, utilization, etc., and its future impact on social, ethical, and legal systems.
Also called biomedical technology assessment, health technology assessment.
A methodological and application area of epidemiology concerned with the application of space-based systems (communication, Earth observation, positioning systems, Geographical Information Systems. biostatistics, etc.) in the study of the space and time distribution of health events or disease process in populations. In this broader sense, the term includes applications of all space-based systems to the field of epidemiology.
Telemedicine is a rapidly developing application of clinical medicine where medical information is transferred through interactive audiovisual media for the purpose of consulting, and sometimes remote medical procedures or examinations.
Delivery of health services via remote telecommunications. This includes interactive consultative and diagnostic services.
The sequence of events in time, used as one of the criteria in evaluating causation – the exposure or intervention must have occurred before the outcome to be a plausible cause of the outcome.
Temporality means that the exposure always precedes the effect.
A live birth or stillbirth that takes place between 37 completed and 42 completed weeks of gestational age.
Childbirth at the end of a normal duration of pregnancy, between 37 to 40 weeks of gestation or about 280 days from the first day of the mother's last menstrual period.
Also called full-term birth.
Lists of the technical terms or expressions used in a specific field. These lists may or may not be formally adopted or sanctioned by usage.
The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.
Medical care provided to a patient when referred by one health professional to another with more specialized qualifications or interests. There are two levels of referred care: secondary and tertiary. Secondary care is usually provided by a broadly skilled specialist such as a general surgeon, general internist, or obstetrician.
Refers to medical and related services of high complexity and usually high cost.
Also called tertiary health care.
Synthesis (summary) of secondary level research, i.e. of systematic reviews and meta-analyses in the form of review of reviews..
Intervention after a sign or symptom is present, to reduce the likelihood of persistence or progression.
Measures aimed at providing appropriate supportive and rehabilitative services to minimize morbidity and maximize quality of life after a long-term disease or injury is present.
Any drug (including a biological product for human use), medical device for human use, human food additive, color additive, electronic product, or any other article subject to regulation under the FD&C Act.
A statistical test to assess whether the value of one variable is associated (i.e. varies with) the value of another variable, or whether the presence or absence of a factor is more likely when a particular outcome is present.
The probability below which the clinician decides a diagnosis warrants no further consideration.
Book intended for use in the study of specific subjects, containing systematic presentation of the principles and essential knowledge of the subjects.
While 90% of the global burden of disease is in developing countries, only an estimated 10% of the global resources are spent on disease problems of developing countries.
The point at which iterations among data collection, analysis, and theory development yield a well-developed concept, and further observations yield minimal or no new information to further challenge or elaborate the concept.
The relative equivalency in the efficacy of different modes of treatment of a disease, most often used to compare the efficacy of different pharmaceuticals to treat a given disease.
Human experimentation that is intended to benefit the subjects on whom it is performed.
Informed consent given by someone other than the patient or research subject.
The last third of a human pregnancy, from the beginning of the 29th through the 42nd completed week (197 to 294 days) of gestation.
Maximum number needed to treat (NNT) or number needed to harm (NNH) accepted as justifying the benefits and harms of therapy.
In this study design, data are collected at several times both before and after the intervention; data collected before the intervention allow the underlying trend and cyclical (seasonal) effects to be estimated. Data collected after the intervention allow the intervention effect to be estimated while accounting for underlying secular trends. The time-series design monitors the occurrence of outcomes or endpoints over a number of cycles and determines whether the pattern changes coincident with the intervention.
A description of the data in studies where the analysis relates not just to whether an event occurs but also when. Such data are analyzed using survival analysis. (Also called survival data.)
An alternative, and supposedly simpler, approach to establishing health utilities. Here, the respondent faces a choice between living for a given period of time (t) in the specified health state or a shorter period of time (x) in full health. The duration in full health is altered until the respondent regards the two options as equivalent to each other. The value of the health state is then given by (x/t). As with the standard gamble technique, the method described here needs to be adjusted for short-term conditions.
Proportion of all expected reports in a reporting system received by a given due date.
Usually refers to medically less important (that is, without serious or permanent sequelae), but unpleasant adverse effects of drugs. These include symptoms such as dry mouth, tiredness, etc, that can affect a person’s quality of life and willingness to continue the treatment. As these adverse effects usually develop early on and are relatively frequent, randomized controlled trials may yield reliable data on their incidence.
The sum of all the fixed and variable costs associated with a particular scale of provision of a program or intervention. The greater the scale of provision, the larger will be the total costs.
Total (or national) expenditure on health is based on the following identity and functional boundaries of medical care: Personal health care services + Medical goods dispensed to outpatients = Total personal expenditure on health + Services of prevention and public health + Health administration and health insurance = Total current expenditure on health + Investment into medical facilities = Total expenditure on health.
The sum of general government health expenditure and private health expenditure in a given year, calculated in national currency units in current prices.
The average number of children a hypothetical cohort of women would have at the end of their reproductive period if they were subject during their whole lives to the fertility rates of a given period and if they were not subject to mortality. It is expressed as children per woman.
The total fertility rate (TFR, sometimes also called the fertility rate, period total fertility rate (PTFR) or total period fertility rate (TPFR)) of a population is the average number of children that would be born to a woman over her lifetime if (1) she were to experience the exact current age-specific fertility rates (ASFRs) through her lifetime, and (2) she were to survive from birth through the end of her reproductive life. It is obtained by summing the single-year age-specific rates at a given time.
The expected average number of children that would be born to a woman in her lifetime, if she were to pass through her childbearing years experiencing the age-specific fertility rates prevailing in a given year/period, for a given country, territory, or geographic area.
The degree to which a medicine is poisonous. How much of a medicine can be taken before it has a toxic effect.
An adverse effect produced by a drug that is detrimental to the participant's health. The level of toxicity associated with a drug will vary depending on the condition which the drug is used to treat.
Used with drugs and chemicals for experimental human and animal studies of their ill effects. It includes studies to determine the margin of safety or the reactions accompanying administration at various dose levels. It is used also for exposure to environmental agents. Poisoning should be considered for life-threatening exposure to environmental agents.
A verbatim written version of an interview.
Translational research is a way of thinking about and conducting scientific research to make the results of research applicable to the population under study and is practiced in the natural and biological, behavioral, and social sciences. In the field of medicine, for example, it is used to translate the findings in basic research more quickly and efficiently into medical practice and, thus, meaningful health outcomes, whether those are physical, mental, or social outcomes.
Research that seeks to characterize the sequence of events through which a scientific discovery moves between basic scientists, clinical researchers, practitioners, and consumers, and to find more effective ways to facilitate this process. Translational research can be further specified by the translational phase that it addresses, phase I (basic science to human research or human research to basic science), phase II (human research to practice-based and community-based research or practice-based and community-based research to human research), or phase III (practice-based research to practice and community or practice and community to practice-based research). Phase III translational research is often further divided into dissemination research, implementation research, and diffusion research.
The application of discoveries generated by laboratory research and preclinical studies to the development of clinical trials and studies in humans. A second area of translational research concerns enhancing the adoption of best practices.
In medicine, transmission is the passing of a disease from an infected individual or group to a previously uninfected individual or group.
Used with diseases for studies of the modes of transmission.
The process of intervening on people with the aim of enhancing health or life expectancy. Sometimes, and particularly in statistical texts, the word is used to cover all comparison groups, including placebo and no treatment arms of a controlled trial and even interventions designed to prevent bad outcomes in healthy people, rather than cure ill people.
Procedures concerned with the remedial treatment or prevention of diseases. Also called therapeutics.
An effect attributed to a treatment in a clinical trial. In most clinical trials the treatment effect of interest is a comparison (or contrast) of two or more treatments.
An event that emerges during treatment having been absent pre-treatment, or worsens relative to the pre-treatment state.
A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.
IND stands for Investigational New Drug application, which is part of the process to get approval from the FDA for marketing a new prescription drug in the U.S. It makes promising new drugs available to desperately ill participants as early in the drug development process as possible. Treatment INDs are made available to participants before general marketing begins, typically during Phase III studies. To be considered for a treatment IND a participant cannot be eligible to be in the definitive clinical trial.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, practicability, etc., of these interventions in individual cases or series.
Patient or client refusal of or resistance to medical, psychological, or psychiatric treatment.
Refers to trials which test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
A consistent movement across ordered categories, e.g. a change in the effect observed in studies grouped according to, for instance, intensity of treatment.
A long-term movement or change in frequency, usually upwards or downwards.
A process of prioritizing patients based on the severity of their condition.
The sorting out and classification of patients or casualties to determine priority of need and proper place of treatment.
In a trial of therapy, the physician offers the patient an intervention, reviews the impact of the intervention on that patient at some subsequent time, and, depending on the impact, recommends either continuation or discontinuation of the intervention.
The location(s) where trial-related activities are actually conducted.
A statistician who has a combination of education/training and experience sufficient to implement the principles in this guidance and who is responsible for the statistical aspects of the trial.
Used to refer to a person conducting or publishing a controlled trial.
More than one investigator collects and analyzes the raw data, such that the findings emerge through consensus among investigators.
In qualitative research, an analytic approach in which key findings are corroborated using multiple sources of information.
When publication bias is suspected in a systematic review, investigators may attempt to estimate the true intervention effect by removing, or trimming, small positive-result studies that do not have a negative-result study counterpart and then calculating a supposed true effect from the resulting symmetric funnel plot. The investigators then replace the positive-result studies they have removed and add hypothetical studies that mirror these positive-result studies to create a symmetric funnel plot that retains the new pooled effect estimate. This method allows the calculation of an adjusted confidence interval and an estimate of the number of missing trials.
A diagnostic test correctly indicating that a person does not have the disease.
A diagnostic test correctly indicating that a person has the disease.
Twin studies are one of a family of designs in behavior genetics which aid the study of individual differences by highlighting the role of environmental and genetic causes on behavior.
Methods of detecting genetic etiology in human traits. The basic premise of twin studies is that monozygotic twins, being formed by the division of a single fertilized ovum, carry identical genes, while dizygotic twins, being formed by the fertilization of two ova by two different spermatozoa, are genetically no more similar than two siblings born after separate pregnancies.
Twin study [MeSH - publication type]: work consisting of reporting using a method of detecting genetic causes in human traits and genetic factors in behavior using sets of twins.
A statistical test where a difference between two groups is tested without reference to the expected direction of the difference, for example whether a risk factor, such as use of hormonal contraception will increase or decrease the incidence of a condition. A two-tailed test will need a larger sample size than a one-tailed test.
A conclusion that a treatment works, when it actually does not work. The risk of a Type I error is often called alpha. In a statistical test, it describes the chance of rejecting the null hypothesis when it is in fact true. (Also called false positive.)
A conclusion that there is no evidence that a treatment works, when it actually does work. The risk of a Type II error is often called beta. In a statistical test, it describes the chance of not rejecting the null hypothesis when it is in fact false. The risk of a Type II error decreases as the number of participants in a study increases. (Also called false negative.) Table of contents:
Patients, clinicians, those monitoring outcomes, judicial assessors of outcomes, data analysts, and manuscript authors are aware of whether patients have been assigned to the experimental or control group.
A comparison between two treatment groups that will give an unbiased estimate of the effect of treatment due to the study design. For a comparison to be unconfounded, the two treatment groups must be treated identically, apart from the randomized treatment. For instance, to estimate the effect of heparin in acute stroke, a trial of heparin alone versus placebo would provide an unconfounded comparison. However, a trial of heparin alone versus aspirin alone provides a confounded comparison of the effect of heparin.
A clinical trial that has no control group.
The quotient between the number of deaths in children under 5 year of age in a given year and the number of live births in that year, for a given coun