I am trying to determine why I received the following errors when I ran GEE on my data using logor=exch and why I did not receive those errors when I ran my data with type=exch: Error in log odds ratio regression computation. Error in parameter estimate covariance computation. Error in estimation routine. The respective code is listed below: proc genmod data=both; class inhalyn (ref="0") grades (ref="3") wave uid / param=ref; model inhalyn=grades / dist=bin link=logit; repeated subject=uid / withinsubject=wave logor=exch; estimate "1 vs 3" grades 1 0 / exp; estimate "2 vs 3" grades 0 1 / exp; run; proc genmod data=both; class inhalyn (ref="0") grades (ref="3") wave uid / param=ref; model inhalyn=grades / dist=bin link=logit; repeated subject=uid / withinsubject=wave type=exch; estimate "1 vs 3" grades 1 0 / exp; estimate "2 vs 3" grades 0 1 / exp; run; SAS was able to give me estimates and ORs when using type=exch. Inhalyn is a binary variable and grades is a 3-level categorical variable. I used the same code for other 3-level categorical variables and was able to get estimates and ORs when using logor=exch, so I'm trying to figure out what's different about this variable/scenario that would require type=exch instead of logor=exch. Your help is much appreciated!
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