ABSTRACT
Survival data refer to observations of subjects after intervention and over a certain length of time (even lifetime) until the occurrence of an event. In clinical research, an event can be the time from treatment to death in cancer research, the time from treatment in a bone fracture in osteoporosis clinical trials, and so on. PROC LIFETEST, one of the survival analysis procedures in SAS/STAT, computes the Kaplan-Meier estimates of the survival functions and compares survival plots (curves) between different treatment groups (Kuhfeld and So, 2013). The log-rank test is usually used to analyze the intervention effects in different groups.
