Error using MuMIn dredge with glmer.nb
Fiona Mae Caryl <fcaryl at ...> writes:
Dear R Users, I receive an error message when using the dredge function in MuMIn on a glmer.nb glmerMod object. "Error in dredge(cm.nb) : call to 'global.model' contains '...' arguments and cannot be updated: glmer(formula = CM ~ BUSH + FRAG + I(TREE^2) + (DWELL * TREE) + (1 | XSCAPE), data = ..2, family = negative.binomial(theta = th))"
Before I provide an example I thought it best to ask: is it possible to dredge a glmer.nb glmerMod object?
Well, at the moment (as you can see) no. In principle we should be able to make this possible, but glmer.nb has not been very thoroughly tested, and involves another level of nesting of operations within functions, so it doesn't particularly surprise me that this fails. https://github.com/lme4/lme4/issues/176 highlights a closely related problem.
I have successfully dredged other glmerMod objects as well as negative binomial mixed model objects from glmmadmb.
Any pointers would be much appreciated as the fitted vs residual plots from glmer.nb are much less skewed than those from glmmadmb.
Well, that probably has something to do with the way the residuals are calculated (which also hasn't been carefully tested, neither in glmmADMB nor in glmer.nb)! It probably makes more sense to double-check the way the residuals are calculated in both cases and see why they don't agree. Do your fits themselves agree (i.e., the fixed-effect and variance-covariance estimates match closely) if you try the same model in glmer.nb and glmmADMB?
Best wishes, Fiona --------------------------------------------- Dr Fiona Mae Caryl Research Fellow Australian Research Centre for Urban Ecology School of Botany
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