Dear R-friends, I would very much appreciate any direction you can give me regarding the following: I am trying to specify a model with three random effects (var1, var2 and constant) in two levels (nested in pair): lme(dependend ~ age + gender, random=list(pair = pdIdent(~var1 + var2 +1)), data=data, method = "ML", na.action="na.omit") this works, the equivalent with formula also works (although only for method=" REML"??) lme(dependend ~ age + gender, random=~var1 + var2 + 1|pair, data=data, method = "REML", na.action="na.omit") Now my problem: how do I specify a random effect with var1 nested in individuals and var2 and constant nested in pair: lme(dependend ~ age + gender, random=~var1 + (var2 + 1|pair), data=data, method = "REML", na.action="na.omit") Is not working (invalid formula for groups). I am trying to specify a mixed effect model as outlined in biometrical Modeling of Twin an Family Data Using standard mixed model software, Rabe-Hesketh et al , Biometrics 2008, 64:280-288 Any suggestion would be much appreciated. Marco
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
