Hi, I run a mixed model for a repeated mesures analysis. I have 2 factors : group factor with 4 levels and week factor with 5 levels. I want to test the time effect in each group and the group effect in each week. I used the following code to test time effect in group 1 and group effect in week 2 : proc mixed data=rawdata; class mice group week; model col1 = group week week*groupe ; repeated / subject=mice type=cs; contrast "Time effect in group 1" week -1 0 0 0 1 groupe*week -1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, week 0 -1 0 0 1 groupe*week 0 -1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, week 0 0 -1 0 1 groupe*week 0 0 -1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, week 0 0 0 -1 1 groupe*week 0 0 0 -1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0; contrast "Group effect at time 2" group -1 0 0 1 week*group 0 0 0 0 -1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0, group 0 -1 0 1 week*group 0 0 0 0 0 -1 0 1 0 0 0 0 0 0 0 0 0 0 0 0, group 0 0 -1 1 week*group 0 0 0 0 0 0 -1 1 0 0 0 0 0 0 0 0 0 0 0 0; run; It is working for "Time effect in group 1" but it does not work for "Group effect at time 2". In the log, I can see " the contrast is not estimable". Please, can you let me know if my first contrast is correct and if so, why the second one does not work? Many thanks Matthieu
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