[R-sig-ME] Fitted values for binomial family in lme4a{glmer}

[Douglas Bates]

On Tue, Nov 23, 2010 at 12:05 PM, Kevin E. Thorpe
<kevin.thorpe at utoronto.ca> wrote:
> I searched the archives and found questions like this with no definitive
> answers.  I also did not find an answer in the lme4a help files.

> I'm using lme4a_0.999375-57 in R version 2.12.0 Patched (2010-11-07 r53537) on
> Platform: i686-pc-linux-gnu (32-bit).
>
> I've fit a model with glmer() using the binomial family.  I'm wondering what
> fitted() gives on the result.  It appears that fitted() on a regular logistic
> model fit with glm() returns fitted probabilities.  It looks like the same
> behaviour occurs with a glmer() object, but some confirmation would be nice.

Yes, the value of the fitted method is on the scale of the mean
response, which is the probability scale when using a binomial family.