Hi Ben, Thank you so much for your helpful advice! I changed the lmer model to REML=FALSE and the best-fitting model in dredge is MUCH more similar to what I found with MCMCglmm.
My best, Corina -- Dr. Corina Logan Leverhulme Early Career Research Fellow Department of Zoology University of Cambridge [email protected] www.CorinaLogan.com On Jul 18, 2015, at 18:06, bbolker [via R] <[email protected]> wrote: Corina <itsme <at> CorinaLogan.com> writes: > > Hello, > I am running my full model (fm) through lmer() and MCMCglmm() using the > default settings: > > model.lmer <- lmer(fm) > model.MCMCglmm <- MCMCglmm(fm) > [snip] > However, when I run the models through dredge(): > > dredge(model.lmer) > dredge(model.MCMCglmm) > It ranks the models very differently for lmer() and MCMCglmm() in > the model selection tables, even though I used the default settings > for dredge() as well (ranked by AICc). I would assume the difference > is because lmer() uses REML and MCMCglmm() uses Bayes Rule, however > if this is the case then why weren’t the summary outputs different > as well? [snip] This question *might* be better on [hidden email] <x-msg://2/user/SendEmail.jtp?type=node&node=4710029&i=0> ... You shouldn't be comparing models with fixed effects that are fitted with REML -- try refitting with REML=FALSE. The model comparison functions in the lme4 package (e.g. anova()) try to stop you from making this mistake, but I'm not sure the MuMIn::dredge does. ______________________________________________ [hidden email] <x-msg://2/user/SendEmail.jtp?type=node&node=4710029&i=1> mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help <https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html <http://www.r-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code. If you reply to this email, your message will be added to the discussion below: http://r.789695.n4.nabble.com/Why-does-dredge-rank-models-differently-for-lmer-and-MCMCglmm-tp4710020p4710029.html <http://r.789695.n4.nabble.com/Why-does-dredge-rank-models-differently-for-lmer-and-MCMCglmm-tp4710020p4710029.html> To unsubscribe from Why does dredge() rank models differently for lmer() and MCMCglmm()?, click here <http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=4710020&code=aXRzbWVAQ29yaW5hTG9nYW4uY29tfDQ3MTAwMjB8LTIwNjUwNjEyMzQ=>. NAML <http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> -- View this message in context: http://r.789695.n4.nabble.com/Why-does-dredge-rank-models-differently-for-lmer-and-MCMCglmm-tp4710020p4710129.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
