Survival Analysis Using SAS®: A Practical Guide

The SMOOTH Macro

The SMOOTH macro produces nonparametric plots of hazard functions using a kernel smoothing method (Ramlau-Hansen 1983). It works with either PROC LIFETEST or PROC PHREG. When used after PROC LIFETEST, the macro requires the data set produced by the OUTSURV option in the PROC LIFETEST statement. With PROC PHREG, the macro uses the data set produced by the BASELINE statement, and it specifically requires the survival probabilities. If there is more than one survival curve in the BASELINE or OUTSURV data set (e.g., if a STRATA statement is used in either procedure), SMOOTH produces multiple smoothed hazard curves on the same axes. The shape of the smoothed curve is heavily dependent on the WIDTH parameter that controls how much ...