<joris.dewolf <at> cropdesign.com> writes: > Have a look at Rnew volume 5/1 (http://cran.r-project.org/doc/Rnews/) where > Doug Bates explains this nicely. Consider using lme4 for your purpose. But be aware of <http://finzi.psych.upenn.edu/R/Rhelp02a/archive/76742.html> if you currently want to use lme4. Dieter