Hi Steve, thanks for your suggestion. Unfortunately it seems not working. I tried this model: PROC GLIMMIX DATA=mydata PLOTS=ALL ; CLASS animal group compound repeat ; MODEL signal = groupt|compound ; RANDOM repeat / SUBJECT=animal ; RANDOM compound / SUBJECT=animal*repeat TYPE=UN ; LSMEANS group|compound / CL ; RUN; but it doesn't work, this is the log: WARNING: MIVQUE0 estimate of profiled variance is linearly related to other covariance parameters. NOTE: Convergence criterion (FCONV=2.220446E-16) satisfied. NOTE: At least one element of the gradient is greater than 1e-3. NOTE: A linear combination of covariance parameters is confounded with the residual variance.
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