[R-sig-ME] warnings ranef and design of a binomial model

[Douglas Bates]

I think we would need at least the output from traceback() to see
where the error is occurring.  Better yet would be to have access to
the data so we could try out the model fits.  Sometimes these errors
show up deep inside another computation.  Does

ranef(mod.glmer)

produce a result?  I'm trying to decide if the problem is in the
postVar part or in the ranef part.

On Wed, Sep 10, 2008 at 5:29 AM, Robert ESPESSER
<Robert.Espesser at lpl-aix.fr> wrote:
> Dear R users,
>
> I have a question about model design.
> One group of 20 subjects run the A experiment, with 17 binary responses by subject.
> An other group of 20 subjects run the 2 experiments B and C, with 20 binary responses by subject,
> for both of the 2 experiment.
>
> I want to study the effect of the  factor "expe"
> I tried this covariance model:
> mod.glmer <-  glmer( vd ~ dlms*expe +(1|subject) +(0+dlms|subject) ,
>              family=binomial, ....)
>
> where:
> dlms is a numeric factor (-2,-1,0, 1,2)
> expe is a 3 levels factor , coding the experiment (A or B or C)
>
> vd is the success/fail matrix.
>
> The model with a random slope is clearly better than an intercept-only model.
>
> the results look plausible, ranef(mod.glmer, postVar=T) was OK for the
> Intercept, but failed
> to compute the postvar of the random slope , with these warnings:
> 1: In min(x): no argument found for min; Inf is returned
> It's the same for max.
>
> I'm  suspecting  that my model is perhaps badly designed , concerning the
> unbalanced repartition of the subjects across the experiments. Is it correct ?
>
> Thanks for any comments or suggestions.
>
> ####
> sessionInfo()  is:
> R version 2.7.2
>
> lme4_0.999375-26
> Matrix_0.999375-13
>
>
> Robert Espesser
> Laboratoire Parole et Langage  UMR 6057, CNRS
> 29 Av. Robert Schuman  13621 AIX    (FRANCE)
> Tel: +33 (0)4 42 95 36 26   Fax: +33 (0)4 42 95 37 88
> http://www.lpl-aix.fr
>
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