Hello,    I have a dataset which has observations before and after a treatment in 2 conditions. So I have "post" and "Pre" treatment measurements in condition "A" and "post" and "pre" treatment measurements in condition "B". I want to compare (Post - Pre) in condition A with (Post - Pre) in condition B. For that, I wrote the following code(time represents pre and post):    PROC MIXED method=REML, data=my_data; class subj_id condition time gender; model value = time condition gender time*condition; random int / subject=subj_id type=UN; contrast 'my_contrast' time*condition 1 -1 -1 1; RUN; Because I am new to SAS, I don't know whether this code does the same thing that I want or not. Can you help me to understand it better. Thanks!  ... View more