AFAIK likelihood ratio tests are preferable, especially when you're interested in testing several fixed-effects simultaneously. However, since in GLMMs the likelihood cannot be calculated explicitly one could wonder how does this affect LRTs.
Adaptive Gaussian quadrature is know to provide the best approximation; however, taking into account the random-effects structure in your model I doubt if it'd ever convergence in this year. Thus, I think Laplace is the best you can have in a reasonable computing time. Regarding `method = "ML"' I think this refers to the linear mixed model case where you also have the option for REML (the default). I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Martin Henry H. Stevens" <[EMAIL PROTECTED]> To: "R-Help" <[email protected]> Sent: Friday, June 09, 2006 3:55 PM Subject: [R] binomial lmer and fixed effects > Hi Folks, > > I think I have searched exhaustively, including, of course R-help > (D. > Bates, S. Graves, and others) and but I remain uncertain about > testing fixed effects with lmer(..., family=binomial). > > I gather that mcmcsamp does not work with Do we rely exclusively on > z > values of model parameters, or could we use anova() with likelihood > ratios, AIC and BIC, with (or without) method="ML" (with didn't seem > right to me)? > > I also received an error using adaptive Gaussian quadrature (but not > Laplacian approximations): > > > mod2 <- lmer(yb ~ reg*nutrient*amd + > + (1|rack) + (1|status) + > + (1|popu) + (1|popu:amd) + > + (1|gen) + (1|gen:nutrient) + (1|gen:amd) + > + (1|gen:nutrient:amd), > + data=datnm, family=binomial, method="AGQ") > Error in lmer(yb ~ reg * nutrient * amd + (1 | rack) + (1 | status) > + : > method = "AGQ" not yet implemented for supernodal representation > > I would really appreciate any and all thoughts or leads. > > Cheers, > Hank Stevens > > > version > _ > platform powerpc-apple-darwin8.6.0 > arch powerpc > os darwin8.6.0 > system powerpc, darwin8.6.0 > status > major 2 > minor 3.1 > year 2006 > month 06 > day 01 > svn rev 38247 > language R > version.string Version 2.3.1 (2006-06-01) > > > > > > Dr. M. Hank H. Stevens, Assistant Professor > 338 Pearson Hall > Botany Department > Miami University > Oxford, OH 45056 > > Office: (513) 529-4206 > Lab: (513) 529-4262 > FAX: (513) 529-4243 > http://www.cas.muohio.edu/~stevenmh/ > http://www.muohio.edu/ecology/ > http://www.muohio.edu/botany/ > "E Pluribus Unum" > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
