[R-sig-ME] Dispersion parameter calculation for Poisson glmer

[Ben Bolker]

 <juwb08 at ...> writes:

> 
> Hi All,
> 
> I would like to calculate a dispersion parameter for a glmer with a  
> Poisson family (in lme4). I found a function posted on this mailing  
> list that had been suggested to use for calculating a dispersion  
> parameter for a glmer with a binomial family. (Found on   
> https://stat.ethz.ch/pipermail/r-sig-mixed-models/2011q1/015383.html )
> 

 [snip]

  Please see slightly more robust code at

http://glmm.wikidot.com/faq#overdispersion_est

It should be applicable to GLMMs generally, although please note all the
boldface warnings about this being a crude approximation of the
overdispersion parameter.