[R-sig-eco] nlme model specification

[David Hewitt]

> I wanted to point out that BIC doesn't need to be though of in a Bayesian
> context and there is no need for the user to explicitly specify a prior to
> use BIC -- it is simply -2*(loglik) + k*log(n), with k being the number of
> estimated parameters and n the sample size.
> 

Yep, my mistake. BIC doesn't need priors, as stated on the first page of the
article I pointed out! (It had been a while, OK?)

But, as you mention below, with random effects models it's tough to
determine what values you plug in for n and k. Same goes for AICc. I think
this leads back to considering a different overall strategy for model
selection in a random effects context, such as Bayes factors. I am not aware
of the R packages that support Bayesian model selection, but I bet they're
out there.

-----
David Hewitt
Research Fishery Biologist
USGS Klamath Falls Field Station (USA)
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