Hi, I'm trying to build a hierarchical logistic regression model with lme4 package, but I have a problem on selecting the variables to include in this model.
In a simple logistic regression, using Forward selection, i use a likelihood ratio test to check which variables i should include in the model, using the function add1(). The problem is that this function doesn't work with the hierarchical model that i'm trying to achieve. Example: model<- glmer(y ~ (1 | group)+x+sex+age, family = binomial("logit"), data = db) add1(model, db, test="Chisq") Error: $ operator not defined for this S4 class I know that the drop1() function works fine to do a backward selection, but the problem is that i have 40 variables, and which time i use drop1() i have to wait a loooooong time to get a result... Is there any alternative to add1()? I mean, i don't want to use anova(model1,model2) because i would have to do all the models by hand... Thanks a lot guys, Bruno -- View this message in context: http://r.789695.n4.nabble.com/add1-alternative-tp4648215.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org 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.