Clinical significance is different from statistical significance, which focuses on making a mathematical determination about whether the change might or might not be expected to happen by chance.
Example: Suppose the results of a clinical trial show that people with sleep disorders who took a particular supplement slept 10 minutes longer each night than people who took a placebo and the difference of 10 minutes was statistically significant. Also, the results of earlier research show that sleeping at least 60 minutes longer each night would help a person with a sleep disorder feel well rested when they wake up. The results of this study would not be judged as clinically significant because the people who took the supplement only slept an additional 10 minutes and not the 60 minutes experts have determined can help a person with a sleep disorder feel well rested when they wake up. But the study results would still be considered statistically significant.