Dear all, I??ve got problems concerning crossed random effects and nested effects using the function "lme": I have two crossed random effects and I would like to nest each of them in a fixed factor and also test for the effects of these fixed factors. At the moment my model looks like this: Lme1<-lme(x~(A+B+C+D+E)^2, random=list(grp =pdBlocked(list(pdIdent(~Z-1),pdIdent(~W-1))))) I would like to nest Z in A and C (C/A/Z), an W in B and C (C/B/W) (A,B,C being 3 fixed factors with two levels). If you have a response to this kind of problem, could you please help me. Thank you, Anne Berthouly