Thank you for the reply. My SAS version is 8.3 Update 3 (8.3.3.181) (64-bit). I tried once again with REF-option in Class statement, and I noticed that it seems to work just fine with dichotomous predictors, but not if I have three classes or more. For instance, I have predictor variable called education, and it has 3 classes (low, middle and high). I would like to use high as my reference category. And when I define it with class ref-option, it sets the middle-class as reference. The same thing happens with other variables that have 3 or more classes (e.g. perceived income, or family living arrangements) It does not recognise the right reference group. Any tips for that?
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