Survival Analysis Using SAS®: A Practical Guide

The WLW Macro

The WLW macro uses the method of Wei, Lin, and Weissfeld (1989) to produce tests and partial likelihood estimates for multivariate survival data, for example, repeated events. This method produces standard errors and test statistics that correct for possible dependence among the observations. The macro incorporates a SAS/IML program, written by Ying So, that appears in SAS/STAT Software: Changes and Enhancements, Release 6.10. The input data set must have one record for each spell (a time interval from origin to death or censoring). Multiple spells for a single individual must have a common identification number. Additional background is provided in The WLW Method in Chapter 8, “Heterogeneity, Repeated Events, and Other Topics,” ...