Hello! I am emailing you with a brief coding question. I need to fit a marginal logistic regression model and used the following code:   PROC GENMOD DESCENDING;    CLASS id trt (REF=first) week (REF=first);    MODEL y=trt week trt*week / DIST=BINOMIAL LINK=LOGIT;    REPEATED SUBJECT=id / WITHINSUBJECT=week TYPE=EXCH; RUN;   unfortunately, I only get estimates from my model but cannot get 95%CIs and SE. Do you have any idea what could be wrong with the code?   I get the following error message: error in computing the variance function error in parameter estimate covariance computation error in estimation routine ... View more