Dear Laura, There is no car::vif() method for gls objects, but the approach that car:::vif.lm() uses -- to compute VIFs (and generalized VIFs) from the correlation matrix of the coefficients -- should be applicable to models fit by gls().
I'll take a look a providing a vif.gls() method when I have some time, but, especially if you want VIFs, as opposed to GVIFs, you should be able to do the computations yourself. I hope this helps, John ------------------------------------------------ John Fox, Professor McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ On Tue, 20 May 2014 13:26:58 +0000 Laura Riggi <laura.ri...@slu.se> wrote: > Dear all, > I am running a gls and I would like to check the vif of my model. It seems > that the vif function in the car package and the vif.mer function available > online do not work for gls. Would you know of a method to measure variance > inflation factors for GLS? > Thank you > Laura > > > > [[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. ______________________________________________ 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.
