[R-sig-ME] [Fwd: Re: Wald F tests]

Goedhart, Paul paul.goedhart at wur.nl
Mon Oct 13 16:52:31 CEST 2008


Apparently Ben Bolker and Douglas Bates have different opinions on
testing fixed effects in GLMMs (see below). Does anyone know of any
(simulation) papers on this issue?

Ben Bolker wrote
> But ... LRTs are non-recommended (anticonservative) for comparing 
> fixed effects of LMMs hence (presumably) for GLMMs, unless sample 
> size (# blocks/"residual" total sample size) is large, no?

Douglas Bates wrote:
> If I were using glmer to fit a generalized linear mixed model I would 
> use likelihood ratio tests rather than Wald tests. That is, I would 
> fit a model including a particular term then fit it again without that

> term and calculate the difference in the deviance values, comparing 
> that to a chi-square.

Paul Goedhart, Biometris, Wageningen UR, The Netherlands

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