The two models that you compare differ in their fixed effects. As far as lme had been concerned, the anova gave a warning because one should not compare two models differing in their fixed effects if they had been estimated with REML (Pinheiro & Bates, 2000).
I guess the issue is still the same using lmer (but anyone please correct me, if I am wrong) but perhaps the warning message is currently not implemented. Regards, Lorenz - Lorenz Gygax Centre for proper housing of ruminants and pigs Swiss Federal Veterinary Office Agroscope Reckenholz-Tänikon Research Station ART > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Darren M. Ward > Sent: Thursday, October 05, 2006 5:18 PM > To: [email protected] > Subject: [R] lmer BIC changes between output and anova > > list, > > i am using lmer to fit multilevel models and trying to use > anova to compare the models. however, whenever i run the > anova, the AIC, BIC and loglik are different from the > original model output- as below. can someone help me out > with why this is happening? (i'm hoping the output > assocaited with the anova is right!). > > thank you, > > darren > > > unconditional<-lmer(log50 ~ 1 + (1 | Stream:Site) + > (1|Stream), data) > > summary(unconditional) > Linear mixed-effects model fit by REML > Formula: log50 ~ 1 + (1 | Stream:Site) + (1 | Stream) > Data: data > AIC BIC logLik MLdeviance REMLdeviance > -138.8 -132.8 72.42 -150.4 -144.8 > > > > nosection<-lmer(log50 ~ 1 + meanlogATS + residuallogATS + > (1 | Stream:Site) + (1|Stream), data) > > summary(nosection) > Linear mixed-effects model fit by REML > Formula: log50 ~ 1 + meanlogATS + residuallogATS + (1 | > Stream:Site) + (1 | Stream) > Data: data > AIC BIC logLik MLdeviance REMLdeviance > -140.8 -130.7 75.4 -168.9 -150.8 > > > > anova(unconditional, nosection) > Data: data > Models: > unconditional: log50 ~ 1 + (1 | Stream:Site) + (1 | Stream) > nosection: log50 ~ 1 + meanlogATS + residuallogATS + (1 | > Stream:Site) + > unconditional: (1 | Stream) > Df AIC BIC logLik Chisq Chi Df > Pr(>Chisq) > unconditional 3 -144.370 -138.294 75.185 > > nosection 5 -158.861 -148.734 84.430 18.491 2 > 9.657e-05 *** > > ______________________________________________ > [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 > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ [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 and provide commented, minimal, self-contained, reproducible code.
