Message-ID: <AANLkTimEswD8D4hFzlHfAZWgyeMui65vaPLOcSoU774y@mail.gmail.com>
Date: 2010-05-31T14:12:50Z
From: Douglas Bates
Subject: complex residual variance
In-Reply-To: <FF7B1337-4CE2-4A1D-A19E-84203147BBA8@ua.ac.be>
On Mon, May 31, 2010 at 8:47 AM, Sven De Maeyer <sven.demaeyer at ua.ac.be> wrote:
> Hi all,
>
> I'm not a frequent user of Lme4 and I have the habit to use mlwin for
> multilevel analyses. Nevertheless I'm willing to master lme4 further.
>
> In my research I'm often faced with the situation where level 1 variance (or
> residual variance in the mixed effects framework) isn't constant. E.g. I
> have longitudinal data on children, with multiple measurements
> (observations) of these children at a certain moment. As children get older
> these measurements seem to vary more and more. So the residual variance
> itself is a function of time. As a consequence there is heteroscedasticity.
> ?Is there a possibility to explicitly model this in lme4? I know how to do
> it in mlwin, but is it possible in lmer?
Not at present.