Is anyone else using the 'geepack' package? >>> From: "Steve Taylor" <steve.tay...@aut.ac.nz> To:<r-help@r-project.org> Date: 11/Feb/2010 11:28 a.m. Subject: [R] using step() with package geepack I'm using the package geepack to fit GEE models.
Does anyone know of methods for add1 and drop1 for a 'geeglm' model object, or perhaps a method for extractAIC based on the QIC of Pan 2001? I see there has been some mention of this on R-help a few years ago (RSiteSearch("QIC")). The package does provide an anova method for its model objects, and update() seems to work: library(geepack) data(dietox) # the example from ?geeglm # GEE model, using gaussian instead of poisson: gee1 <- geeglm(Weight~1, data=dietox, id=Pig, family=gaussian, corstr="ar1") gee2 <- update(gee1, ".~.+Time") anova(gee1, gee2) # gives a p-value for adding the Time variable step(gee2, direction="forward") # fails cheers, Steve [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R ( http://www.r/ )-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ 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.