Statistical Significance

Statistical significance indicates that an observed result is unlikely to have occurred by random chance alone, given a pre-specified threshold (alpha level, typically 0.05). When p < 0.05, researchers reject the null hypothesis and conclude the effect is 'statistically significant.' However, statistical significance does not equal clinical significance — a supplement that produces a statistically significant but tiny improvement may not be meaningful for patients. Multiple comparison corrections (Bonferroni, false discovery rate) are needed when testing multiple outcomes to prevent inflated false-positive rates.