[R-sig-ME] Extracting random effect variance from a MuMIn-averaged object of several glmer models

[Nathan Jero]

Hi everyone,

I'm working on analyzing the results from a trial of a new animal
management technology, with a random intercept to capture variance
between animals (I have multiple measurements of each animal).  No
single model from my candidate set is obviously the best (AIC weights
< 0.95, several models with delta AIC < 10), so I am planning on using
MuMIn::model.avg to obtain an averaged model for inference.

However, the random effect variance represents differences in how
animals respond to the technology and is therefore of interest to me.
Unfortunately, while obtaining an averaged model object and
coefficients for the fixed effects has been easy, the random effect
variance is not reported in summary(averaged.mod) and I haven't found
another way to extract it from an object of class 'averaging' created
by model.avg.  Is there a way to do this?

All candidate models were fit using the same random effect structure
and dataset in glmer() with the binomial family and logit link.

I'll freely admit my lack of statistical knowledge, so if there are
theoretical issues with this idea, I would love to learn.

Thanks!
Nathan

-- 
Nathan Jero
M.S. student, Animal & Rangeland Science
Rangeland Ecology Lab
University of Nevada, Reno