Hello all,
I am working on a 3 period, 4 treatment, crossover PK study in which the randomization has a partially balanced design of 4 sequences. There are 20 subj with 5 subj/sequence (ABC, BAC, ABD, BAD). If I use the bioequivalence wizard to determine BE with say, B as the reference, the LSMs are "not estimable" and as a result, no BE estimates can be obtained. The error message in the log says: "ERROR 11016: Numerical problem when computing satterthwaite df." The BE setup is standard (form, seq, per = fixed, sub(seq) = random) .
Can someone shed light on how Winnonlin handles LSM for unbalanced designs of >2 periods?
Thanks in advance,
Mike