stata.com stpower — Sample size, power, and effect size for survival analysis Syntax Description Remarks and examples Methods and formulas References Also see Syntax

Sample-size determination stpower cox [...] [ ,...] stpower logrank [...] [ ,...] stpower exponential [...] [ ,...] Power determination stpower cox [...] , n(numlist) [...] stpower logrank [...] , n(numlist) [...] stpower exponential [...] , n(numlist) [...] Effect-size determination stpower cox, n(numlist) { power(numlist) | beta(numlist) } [...] stpower logrank [...] , n(numlist) {power(numlist) | beta(numlist) } [...] See [ST] stpower cox, [ST] stpower logrank, and [ST] stpower exponential. Description stpower computes sample size and power for survival analysis comparing two survivor functions using the log-rank test or the exponential test (to be defined later), as well as for more general survival analysis investigating the effect of a single covariate in a Cox proportional hazards regression model, possibly in the presence of other covariates. It provides the estimate of the number of events required to be observed (or the expected number of events) in a study. The minimal effect size (minimal detectable difference, expressed as the hazard ratio or the log hazard-ratio) may also be obtained for the log-rank test and for the Wald test on a single coefficient from the Cox model. This entry provides an overview of the relevant terminology, theory, and a few examples. For more details, see the entries specific to each stpower subcommand. Also see [PSS] power for power and sample-size analysis for other statistical methods. 1 2 stpower — Sample size, power, and effect size for survival analysis Remarks and examples Remarks are presented under the following headings: Theory and terminology Introduction to stpower subcommands Sample-size determination for survival studies Creating output table