[R-sig-ME] Comparing mixed models

[Carlos Barboza]

Dear all,
why Anova type III function gives different results if I change the names
of a categorical factor? I suspect that is because contrast type but it's
something strange get different results using the same data.
thank you

Em sáb., 7 de mai. de 2016 às 12:26, Carlos Barboza <
carlosambarboza using gmail.com> escreveu:

> 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-freedom-for-a-random-effect
>
>   Follow-ups to r-sig-mixed-models using 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
>
>
>
>

-- 
Universidade Federal do Rio de Janeiro (UFRJ)
Instituto de Biodiversidade e Sustentabilidade - NUPEM
Caixa Postal 119331, CEP 27910-970
Macaé, RJ, Brazil
https://www.macae.ufrj.br/nupem/
http://lattes.cnpq.br/3629226944950076
https://scholar.google.com.br/citations?user=p-PRvd4AAAAJ&hl=pt-BR
https://www.researchgate.net/profile/Carlos_Barboza3

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