Friends of lme, following the documentation of fit.contrast in package gmodels, it should be possible to use it with lmer. At least with sim.lmer=TRUE and lmer(not 2), because the latter has no mcmcsamp yet. I could not get this to work. UseR error? ------------------ library(gmodels) library(lme4) options(show.signif.stars = FALSE) data(ergoStool) fm1 <- lmer(effort ~ Type + (1|Subject), ergoStool) mcmcsamp(fm1) ## works fit.contrast(fm1,"Type",c(1,1,0,0),sim.lmer=TRUE) # Not an applicable method ------------------ Note: I am well aware of the discussion about df/lmer in http://wiki.r-project.org/rwiki/doku.php?id=guides:lmer-tests http://finzi.psych.upenn.edu/R/Rhelp02a/archive/76742.html so I don't expect the method to work with sim.lmer=FALSE. And yes, the example is simple and results can be obtained directly. However, I looking for an easy-to-use general contrast test, and fit.contrast and estimable are the only ones I know of that work rather generally. Dieter