# Verify the values found in the Royston paper library(survival) pbc2 <- na.omit(pbc[,-1]) # no id variable, no missings pfit1 <- coxph(Surv(time, status==2) ~ . + log(bili) - bili, pbc2, ties="breslow") # backwards elimination was used to eliminate all but 8 pfit2 <- coxph(Surv(time, status==2) ~ age + log(bili) + edema + albumin + stage + copper, data=pbc2, ties="breslow") temp <- rbind(royston(pfit1), royston(pfit1, adjust=TRUE), royston(pfit2), royston(pfit2, adjust=TRUE)) all.equal(round(temp[,1], 2), c(2.86, 2.56, 2.69, 2.59))