Hello, I've been caught up in an issue in Proc Glimmix. For the same data, the same model and the same procedure, but I get different covatiance parameter estimate tables. The treatment has 3 levels. The model is : proc glimmix data=analysis initglm method=laplace; class trial rep treatment; model event/group_total=treatment; nloptions tech=newrap maxit=400; random trial rep(trial); run; Covariance parameter estimates Cov Parm Estimate Standard error trial 0 . rep(trial) 0.3120 . Type III Test of Fixed effect effect Num DF Den DF F value treatment 2 24 53.62 <.0001 However,if I sort the data by treatment first and re-run the glimmix procedure, I have different above tables: Covariance parameter estimates Cov Parm Estimate Standard error trial 0 0.2204 rep(trial) 0.3109 0.4130 Type III Test of Fixed effect effect Num DF Den DF F value treatment 1 24 162.42 <.0001 The df for numerator is 1. But the treatment has 3 levels, df should be 2. Can anybody explain what causes these different results? Is it because the model is over-specified? Thanks a lot!
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