S3 method to checking proportional hazards

This function checks the proportional hazards assumption in the Cox model using Schoenfeld residuals. This function only return results for strategies based on efficient influence functions.

Usage

zph(x)

Arguments

x

A fitted object returned by the function tteICE, surv.tteICE, or scr.tteICE.

Value

A list of P-values of testing the proportional hazards (PH) assumption in the working Cox models, for each covariate and a global test, stratified by treatment groups.