I would like to test the parallel regression assumption for an ordered logistic regression model using either a score/LM test, or preferably, a Wald/Brant test. I have been unable to find an R function (either in the base or in a package available on cran) that performs either of these tests. Does one exist that I am overlooking or is there code available elsewhere to do this? As background, I am using vglm( ) from the library VGAM to fit the model. I'm estimating the model with code that looks roughly like this: vglm(y~x1+x2+x3, data=mydata, family=cumulative(link = "logit", parallel = T, reverse = T))
Thank you, Rose ______________________________________ Rose Anne Medeiros Statistical Consulting Group UCLA Academic Technology Services http://www.ats.ucla.edu/stat/ ______________________________________________ R-help@stat.math.ethz.ch 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.
