[R-sig-ME] help with lme4

[Douglas Bates]

On Thu, Mar 15, 2012 at 10:35 AM, Sébastien Bonthoux
<bonthoux.sebastien at gmail.com> wrote:
> Dear D.Bates,
> I am using your package lme4 and the function lmer(). I link a metric of
> ecological community specialisation (gaussian distribution) with several
> land use variables and I add a random intercept because my plots are
> clustered. Can you explain me why I obtain a negative deviance (positive
> logLik) ? Is there any problem ?

Generally it is best to send questions like this to the
R-SIG-Mixed-Models at R-project.org mailing list (see instructions at
https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models).  Many of
those who read that list can reply and often much faster than I am
able to.

The short answer to your question is that a negative deviance for a
model with a response measured on a continuous scale is not a problem.
 Probability mass functions for discrete random variables cannot
exceed 1 but probability density functions for continuous random
variables can.  Thus the log-likelihood for a continuous response can
be positive and the deviance negative.

> Thank you for you reply.
> Best regards
>
> --
> Sébastien Bonthoux
>
> Docteur en Ecologie - PhD in Ecology
>
> 02 54 78 05 74
> Ecole Nationale Supérieure de la Nature et du Paysage
> 9 rue de la chocolaterie
> 41 000 Blois
>
>
>