Hey @ all, for a couple of days now I am trying to code an interaction in my "proc mixed" model but I do not succeed. I searched google and SAS.support page but I am not able to translate those solutions to my problem. My question: How do I write the contrast statement If I want to assess the treatment effect from visit 1 to visit 6 taking into account that there is a treatment*visit interaction? Model: %macro LMM (Y=, M=); proc mixed data=work.XXX order=data;        class treatment visit;        MODEL &Y = treatment visit treatment*visit &M /solution ddfm=satterth ; My outcome (y) is the change in a biomarker. Treatment has two levels (placebo vs. active treatment). I have baseline and 5 visits (follow up visits). And a treatment*visit interaction. I tried different solutions but most of the time they are not estimable. Example (gives results but must be wrong): contrast 'XX vs placebo '        treatment 2  -2                                           visit 0 0 0 0 0 0                                           treatment*visit      1 0 0 0 0 1                                                                     -1 0 0 0 0 -1  /divisor=2 cl e; I hope someone can help me. Thank you. Tobias ... View more