Hello Rachel, I don't think that there is any infrastructure for these procedures on lmer objects, yet. If you are willing to use lme instead, then the multcomp package seems to provide post-hoc tests. It is worth noting that there is some doubt as to the validity of the reference distributions for tests of fixed effects in the presence of random effects.
http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-are-p_002dvalues-not-displayed-when-using-lmer_0028_0029_003f Cheers Andrew On Thu, Feb 22, 2007 at 12:32:44PM +0000, R. Baker wrote: > I'm investigating a number of dependent variables using mixed models, e.g. > > data.lmer45 = lmer(ampStopB ~ (type + stress + MorD)^3 + (1|speaker) + > (1|word), data=data) > > The p-values for some of the 2-way and 3-way interactions are significant > at a 0.05 level and I have been trying to find out how to understand the > exact nature of the interactions. Does anyone know if it is possible to run > post-hoc tests on mixed model (lmer) objects? I have read about TukeyHSD > but it seems that this can only be run on anova (aov) objects. > > Any suggestions would be gratefully appreciated! > > Rachel Baker > > -- > -------------------------------------------------------------------------- > PhD student > Dept of Linguistics > Sidgwick Avenue > University of Cambridge > Cambridge > > ______________________________________________ > R-help@stat.math.ethz.ch 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. -- Andrew Robinson Department of Mathematics and Statistics Tel: +61-3-8344-9763 University of Melbourne, VIC 3010 Australia Fax: +61-3-8344-4599 http://www.ms.unimelb.edu.au/~andrewpr http://blogs.mbs.edu/fishing-in-the-bay/ ______________________________________________ R-help@stat.math.ethz.ch 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.