Hi, I'm performing a survival analysis using a large, complex health survey linked to mortality outcomes. I have appended several survey years to create an unweighted sample size of approximately 200,000 observations. With weights, the number of observations is over 2.2 million. I have used PROC SURVEYPHREG to estimate adjusted hazard ratios for several categorical variables. Now I would like to check the proportionality assumption using a time-dependent covariate, as illustrated on page 9200 (page 38 of the chapter 113 pdf) of the SAS/STAT 14.1 User's Guide https://support.sas.com/documentation/onlinedoc/stat/141/surveyphreg.pdf Here's the example from the user's guide: proc surveyphreg data=Test; class A; model T*Status(0)=A X1 X2; X1= T*(A=1); X2= T*(A=2); run; I have modified the code using the variables from my data and tried running it, but SAS does not generate any output. Due to the large size of the dataset, I let it run for over and hour, but SAS just said "running" and never shows anything in the results viewer. Is there a better way to statistically test the proportionality assumption? Thanks, -Jonathan   ... View more