[R] Stratifying level-1 variance with lmer()
Dieter Menne
dieter.menne at menne-biomed.de
Wed Feb 6 09:22:21 CET 2008
David Afshartous <dafshartous <at> med.miami.edu> writes:
> I've fit some models via lme() and now I'm trying to fit similar models with
> lmer() for some simulations I'm running.
>
> The model below (fm1) has an intercept variance that depends on treatment
> group. How would one accomplish a similar stratification for the level-1
> variance, i.e., the within-group or patient variance?
>
> With lme() I was able to do this via:
> update(fm1,
> weights = varIdent(form = ~ 1 | treatment.ind) )
>
> However, this does not work for lmer(). Is there any way around this?
This is not yet implemented. See Douglas Bates'
http://article.gmane.org/gmane.comp.lang.r.lme4.devel/518
Dieter
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