Statistical Significance — What It Means in Clinical Trials
Plain English Definition
Statistical significance means that the results of a trial are unlikely to have occurred by chance alone. It does not necessarily mean the results are large or clinically meaningful — just that they are real. Researchers use mathematical tests to determine whether the difference between the treatment and control groups is statistically significant.
Why It Matters
When a trial result is described as "statistically significant," it means the researchers are confident the treatment effect is real, not just random noise. But always ask: is it also clinically meaningful? A real but tiny improvement may not change your life.
Example
A trial might report: "The difference in progression-free survival was statistically significant (p=0.003)." This means there is only a 0.3% chance the result happened by luck.
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