07-28-2014 02:55 PM
I'm working on a longitudinal model like the one below, with trt having 4 arms (1,2,3 and 4)
What is the syntax to have group 3 to be always the control in all visit*trt interactions in the lsmeans to get the difference?
proc mixed data=visits noclprint empirical;
class ID trt visit;
model dependant= visit trt visit*trt;
repeated visit / subject=ID(trt);
lsmeans visit*trt/diff pdiff ;
ods output LSMeans=means;
ods output Diffs=difference;
Please for your help....
07-29-2014 08:17 AM
I wasn't successful in getting the output I want using CONTROL option; however, I changed coding of arms so that 3 becomes 4 and 4 becomes 3; in this case output was always
which is what I was interested in.
any help regarding syntax without changing coding of groups would be appreciated.