Hello, I am trying to understand why my regressions give me different results when I run the models in SAS or STATA. I am a new SAS user and I am trying to do survival analysis for the first time with SAS. At this point, I have to produce Cox regressions and as I do not know very much abour SAS, I compare the results in SAS with my results from STATA to make sure that I have done the good thing. An example of my dataset would be: data have; input id time1 event1 weight independent_v1 independent_v2; datalines; 1 0 0 0.8 0 1 1 1 0 0.8 0 1 1 2 0 0.8 0 0 1 3 0 0.8 0 0 1 4 0 0.8 0 1 1 5 0 0.8 0 1 1 6 0 0.8 0 1 1 7 0 0.8 0 1 1 8 0 0.8 0 2 1 9 0 0.8 0 2 1 10 0 0.8 0 2 1 11 0 0.8 0 2 1 12 0 0.8 0 2 1 13 0 0.8 0 2 2 0 0 1.1 1 0 2 1 1 1.1 1 0 2 2 . 1.1 1 0 3 0 0 1.01 2 1 3 1 0 1.01 2 1 3 2 1 1.01 2 1 3 3 . 1.01 2 1 4 0 1 0.98 2 1 4 1 . 0.98 2 1 4 2 . 0.98 2 1 4 3 . 0.98 2 1 4 4 . 0.98 2 1 5 0 0 1.13 3 0 6 0 0 1.05 3 0 6 1 0 1.05 3 1 6 2 0 1.05 3 1 6 3 0 1.05 3 1 6 4 0 1.05 3 1 6 5 1 1.05 3 1 6 6 . 1.05 3 1 6 7 . 1.05 1 1 6 8 . 1.05 1 1 7 0 0 0.89 0 3 7 1 0 0.89 0 3 7 2 0 0.89 0 3 7 3 0 0.89 0 3 7 4 0 0.89 0 3 7 5 0 0.89 0 3 7 6 0 0.89 0 3 7 7 0 0.89 0 3 7 8 1 0.89 0 1 7 9 . 0.89 0 1 7 10 . 0.89 0 1 8 0 0 1.1 1 0 8 1 0 1.1 1 1 8 2 0 1.1 1 1 8 3 . 1.1 1 2 8 4 . 1.1 1 2 ; run; As you can see, I have time-invariant and time-varying covariates and my dataset is arranged in a longitudinal way. This is what I code in SAS for the same table "have": proc phreg data = have; class independent_v1(ref='0') independent_v2(ref='0'); id id; model time1*event1(0) = independent_v1 independent_v2 / rl; weight weight; run; This is what I code in STATA for the same table "have": stset time1 [pweight=weight], id(id) failure(event1=1) char independent_v1[omit] 0 char independent_v2[omit] 0 xi: stcox i.independent_v1 i.independent_v2 Does anyone have any clue ?
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