Generally it is best to send questions like this to the
R-SIG-Mixed-Models@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.

Having said that, note that this is a warning message, not necessarily an
error.  The optimization algorithm used in that version of lme4 is
conservative about declaring convergence and can return that message even
when the algorithm has in fact converged.

Others may have suggestions for further diagonostics.


On Fri, Feb 21, 2014 at 3:42 PM, Austin, Peter <peter.austin@ices.on.ca>wrote:

>  Dear Professor Bates,
>
>   I am writing with a question about a warning message that I received
> when I used the glmer function to fit a complementary log-log binary
> regression model that incorporated two different sets of random effects.
> When running the model, I received the following warning message:
>
>
>
> Warning message: In mer_finalize(ans) : false convergence (8).
>
>
>
> However, output was produced, including regression coefficients, their
> associated standard errors, z values, and p-values. From the output,
> everything looked normal. How should I interpret the warning message, and
> what actions, if any, should I take?
>
> Thanks very much,
>
> Peter Austin
>
>
>
> *Peter Austin PhD*
> Senior Scientist, Institute for Clinical Evaluative Sciences
>
> Full Professor, Institute of Health Policy, Management and Evaluation,
> University of Toronto
>
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