[R-sig-ME] Comparing mixed models

[Alex Fine]

There's a newer one out by Bates et al. that is sort of a response to Barr
et al.:  http://arxiv.org/abs/1506.04967



On Tue, May 10, 2016 at 10:52 PM, Jean-Philippe Laurenceau <
jlaurenceau at psych.udel.edu> wrote:

> Dear Ben et al.--I agree with the general practice of trying to estimate
> and retain as many random effects as possible (without estimation issues)
> in a mixed model. However, I was wondering whether anyone had some
> references recommending or arguing for this approach. I am aware of a paper
> on this topic with some simulation work by Barr et al. (2013; Journal of
> Memory and Language), but I would be interested in whether there are
> others. Thanks, J-P
>
> Jean-Philippe Laurenceau, Ph.D.
> Department of Psychological & Brain Sciences
> University of Delaware
>
>
> -----Original Message-----
> From: R-sig-mixed-models [mailto:r-sig-mixed-models-bounces at r-project.org]
> On Behalf Of Ben Bolker
> Sent: Saturday, May 7, 2016 11:35 AM
> To: Carlos Barboza <carlosambarboza at gmail.com>
> Cc: r-sig-mixed-models at r-project.org
> Subject: Re: [R-sig-ME] Comparing mixed models
>
>   My only other comment would be that my standard approach would be to
> retain all random effects in the model unless they are causing difficulty
> in model fitting -- this depends on your goal (confirmation/testing,
> prediction, exploration)
>
> On Sat, May 7, 2016 at 11:26 AM, Carlos Barboza <carlosambarboza at gmail.com
> >
> wrote:
>
> > Dear Dr. Ben Bolker
> >
> > My name is Carlos Barboza and I am a Marine Biologist from the Rio de
> > Janeiro University, Brazil. First it's a pleasure to again have the
> > opportunity to send you a message.The reason for it is a simple doubt:
> > Can I compare AIC from:
> >
> > 1. glmmADMB: Density ~ 1 + 1|Site
> >
> > 2. glmmADMB: Density ~ Sector + 1|Site + Cage
> >
> > Note that they have different random and fixed structures. I know that
> > this is not the best choice to model selection but, I think that the
> > AIC values can be compared.
> >
> > thank you very much for your attention
> >
> >
> >   is Cage a random effect?  Are you intentionally leaving out the
> > intercept in the second case (it will be included anyway unless you
> > use -1)?  In any case, I don't see any obvious reason you can't
> > compare AIC values; see
> >
> > https://rawgit.com/bbolker/mixedmodels-misc/master/glmmFAQ.html#can-i-
> > use-aic-for-mixed-models-how-do-i-count-the-number-of-degrees-of-freed
> > om-for-a-random-effect
> >
> >   Follow-ups to r-sig-mixed-models at r-project.org, please ...
> >
> > sorry, yes, cage was included only to examplify a different random
> > structure in the second case...it should be coded (1|Site) + (1|Cage)
> > yes, I know that the intercept will be included in the second model
> >
> > it's an example of comparing AIC values from mixed models with
> > different fixed and random structures:
> >
> > 1. Density ~ 1 + 1|Site
> >
> > 2. Density ~ Sector + 1|Site + 1|Cage
> >
> > comparing AIC...I beleive that both values can be compared
> >
> > again, thank you very much for your very fast message
> >
> >
> >
> >
>
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>
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-- 
Alex Fine
Ph. (336) 302-3251
web:  http://internal.psychology.illinois.edu/~abfine/
<http://internal.psychology.illinois.edu/~abfine/AlexFineHome.html>

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