Hello all, In lme4 if you want to model two non-nested random effects you code it like this:
mod1 <- lmer(y~x + (1|randomvar1) + (1|randomvar2)) How would you go about to model something similar in nlme? In my database I have two variables for which I have repeated measures, lets call them "individual" and "year". But none of the "individuals" were measured in more than one year. So as I understand it, I should not nest individual in year or visa versa. Someone suggested I do it as above. But I am accustomed to nlme, and dont know how one would code non-nested random effects. In the Pinheiro and Bates book there is an example coded like this: modB <- lme(y~x, + random = pdBlocked(list(pdIdent(~year-1), pdIdent(~individual-1)))) But when I try it I keep getting an error message saying: "Error in getGroups.data.frame(dataMix, groups) : Invalid formula for groups" What am I doing wrong? Thank you, -- View this message in context: http://r.789695.n4.nabble.com/model-non-nested-random-effects-in-nlme-library-tp4321021p4321021.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
