This is perfect, thank you. I have used lsmestimate before, but it slipped my mind to use it in this way. ... View more

I think you should post it at Stat forum. https://communities.sas.com/t5/Statistical-Procedures/bd-p/statistical_procedures And should use DIVISOR= option to replace 1.66667. Check the following: proc mixed data=test; class a b; model y=a b a*b; estimate 'AB12' intercept 1 a 1 0 b 0 1 0 a*b 0 1 0 0 0 0; estimate 'avg ABij' intercept 6 a 3 3 b 2 2 2 a*b 1 1 1 1 1 1 / divisor=6; estimate 'AB12 vs avg ABij' a 3 -3 b -2 4 -2 a*b -1 5 -1 -1 -1 -1 / divisor=6; lsmestimate a*b 'AB12 vs avg ABij' -1 5 -1 -1 -1 -1 / divisor=6; run; The following could learn how to write ESTIMATE : https://support.sas.com/kb/24/447.html ... View more

Thank you, this is perfect, I didn't know about the JOINT option. Just for any others looking at this post, here is the final code with I believe all the correct zeros and everything.      ods output lsmeans=lsms lsmestimate=lsmests; proc mixed data=eff_pop method = reml; class subj trt visit agegroup hist; model chg = trt visit agegroup trt*visit trt*agegroup visit*agegroup trt*visit*agegroup base cont hist / ddfm=kr solution outp=predict; repeated visit / type=un subject=subj; lsmeans trt*visit*agegroup; lsmestimate trt*visit*agegroup 'Difference within age group 1 at visit 4, trt 1 vs. 2' 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, 'Difference within age group 2 at visit 4, trt 1 vs. 2' 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, 'Difference within age group 3 at visit 4, trt 1 vs. 2' 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0/ joint; run; ods rtf close;     ... View more