ClinCalc Statistics

ClinCalc Statistics separates study planning from interpretation tools. Its Fragility Index form takes endpoint counts for control and experimental groups, with total-patient or non-event entry options. The detailed method changes non-events to events in the group with fewer events and repeats a two-sided Fisher exact test until P reaches or exceeds 0.05. The result is the count of changes needed to lose significance, not a sample-size recommendation. The guide says there is no universal good/bad cutoff and places the index alongside P values, confidence intervals and benefit/risk measures. Sample-size, power and NNT tools address separate questions.