[R-sig-ME] lme vs. lmer

Christopher David Desjardins desja004 at umn.edu
Tue Sep 29 20:17:14 CEST 2009

Thanks Ben. I knew about the discussion with the dfs and p-values. I 
guess what I was really wondering was if lme was deprecated, which 
you've answered.

Ben Bolker wrote:
> Christopher David Desjardins wrote:
>> I've started working through Pinheiro & Bates, 2000 and noticed the use 
>> of lme from the nlme package. I am curious if lmer from lme4 has 
>> superseded lme or if lme still holds its own? The reason I ask is that I 
>> have taken a few classes where we've solely used lmer and just read 
>> about lme today. If both functions are on equal footing, can the 
>> p-values from lme be trusted?
>> Thanks!
>> Chris
>   You should read the extended discussion of p-values, degrees of
> freedom, etc. that is on the R wiki (I think) and referenced from the R
> FAQ.  At least in my opinion, (n)lme is still fine (and indeed necessary
> at this stage for fitting heteroscedastic and correlated models).  The
> df/p-value estimates, however, are "use at your own risk" -- you'll have
> to read the literature and decide for yourself.
>   I still think there's room for someone to implement (at least)
> Satterthwaite and (possibly) Kenward-Roger corrections, at least for the
> sake of comparison, but I'm not volunteering.
>   cheers
>     Ben Bolker

Christopher David Desjardins, Ph.D. Student
Quantitative Methods in Education
Department of Educational Psychology
University of Minnesota

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