That's a similar approach to the one I was taking before thinking I needed to go down the random effects path which has greatly confused me. The code I have written for GEE follows the example you provided, however the key difference between my data and the example is that there are no treatments per se, nor is there a control group which makes me confused about how to specify the model when looking at that example.   Here is the code I have previously written - I am unsure whether the repeated measures block is specified correctly. I am also unsure how to interpret the results of this model given the example does not provide an indication that the link is logit. proc genmod data = survey; class id time (ref = "T2") race (ref = "0") district (ref = "0") existingcond (ref = "0") /param = ref; model attsvc1 = time race district age existingcond / dist = bin; repeated subject = id / corr = unstr corrw; run;     ... View more