= Endpoint-specific rare-event sample size
A <sample size> calculation for a binary endpoint requires its own baseline <probability>, not merely the rate of a related outcome. A fatal-event probability equals the probability of the underlying event times its conditional fatality probability; knowing only that product does not identify the incidence of all events. Thus a mortality rate can size a mortality trial but cannot determine the size for all fatal and nonfatal events without further assumptions. The significance level, allocation, target <statistical power> and effect definition must also be specified.
Back to article page
