Restricted Mean Life with Covariates: Modification and Extension of a Useful Survival Analysis Method

Abstract Karrison has presented a method for covariate-adjusted comparison of two groups with respect to survival when the group effect is expected to not be of proportional hazards form. This article describes a simplified procedure for implementing Karrison's basic approach, along with an extended version designed to achieve robustness against misspecification in the underlying analytical model. A simulation study of these techniques is presented, and the techniques are illustrated with an example taken from Karrison. Key Words: Kaplan–Meier curvesStratified Cox modelSurvival analysis.