Power and Sample-Size Analysis for the Royston–Parmar Combined Test in Clinical Trials with a Time-to-Event Outcome: Correction and Program Update

Abstract

The changes made to Royston (2018) and to power_ct are i) in section 2.4 ( Sample-size calculation for the combined test), to replace ordinary least-squares (OLS) regression using regress with grouped probit regression using glm; ii) in section 4 ( Examples), to revisit the worked examples of sample-size estimation in light of the revised estimation procedure; and iii) to update the help file entry for the option n( numlist). The updated software is version 1.2.0.