windows Vista
R 2.10.1
What is the difference (or differences) between lme and lmer? Both appear to
perform mixed effects regression analyses.
Thanks
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
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>>> "John Sorkin" <jsorkin at grecc.umaryland.edu> 10/09/2010 13:21:09 >>> >What is the difference (or differences) between lme and lmer? Bothappear to perform mixed effects regression analyses.>From a user's point of view:- lme only accepts nested random effect; lmer handles crossed random effects - lme has a convenient methof of handling heteroscedasticity; lmer doesn't. - lme gives you p-values; lmer doesn't (there is explanation of why at https://stat.ethz.ch/pipermail/r-help/2006-May/094765.html which, I guess, should not be all that reassuring for lme users either) Steve Ellison ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}}
John Sorkin <jsorkin <at> grecc.umaryland.edu> writes:> > windows Vista > R 2.10.1 > > What is the difference (or differences) between lme and lmer? Both appear toperform mixed effects> regression analyses. > Thanks > John >in a nutshell: lmer is newer, much faster, handles crossed random effects well (and generalized linear mixed models), has some support for producing likelihood profiles (in the development version), and is under rapid development. It does not attempt to estimate residual degrees of freedom and hence does not give p-values for significance of effects. lme is older, better documented (Pinheiro and Bates 2000), more stable, and handles 'R-side' structures (heteroscedasticity, within-group correlations). r-sig-mixed-models is a good place for questions about these packages. Ben Bolker