What answers have you found and why were they unsatisfactory?

First, use AICc, not AIC. See Burnham and Anderson 2002 or Anderson
2008 (Primer).

Second, I think most all literature is rather clear that models with
deltaAICc < 2 are basically equivalent. So of course you should report
support for models in that group, however many there may be. There are
plenty of examples in the literature of language to accompany such
situations. Finally, if you have this kind of model selection
uncertainty, ignoring the advantages of multimodel inference,
including model-averaging, is a rather strange decision.

Dave Hewitt
http://profile.usgs.gov/dhewitt

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From:    Lee Davis <[email protected]>
Subject: AIC and Occam's Razor

I have what might seem to be a simple question regarding AIC and parsimony,
and yet the answers I have found on the subject are unsatisfactory. So,
opinions please.

Here is the scenario:

Let's say that one is using AIC for the selection of nested models to avoid
multiple LRT comparisons. Should you always choose the model with deltaAIC =
0 as the best? What if there is a model with deltaAIC <2 that has fewer
terms? Should it be chosen in the pursuit of parsimony? Or should you report
some support for both models? If so, what is the proper language in this
case?

Let's assume that we are avoiding model averaging.

Thanks,

Lee
--
Lee Davis
Graduate Assistant
State University of New York
College of Environmental Science & Forestry
Department of Environmental & Forest Biology
452 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210

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