glm.predict

R GNU Package to test the parallel regression assumption with the Brand-Test for polr() models.

Example

Here an example how you can use the function brant(). First we estimate an ordinal logistic regression.

data = MASS::survey
data$Smoke = ordered(MASS::survey$Smoke,levels=c("Never","Occas","Regul","Heavy"))
model1 = MASS::polr(Smoke ~ Sex + Height, data=data, Hess=TRUE)
summary(model1)

Now we can test the parallel regression assumption.

library(brant)
brant(model1)

We see that the assumption hold, as we cannot reject H0.

Installation

If you want to install the stable version from CRAN you can do that with the following command:

install.packages("glm.predict")

If you want to install the newest developer version from GitHub, you can do that with the package remotes:

install.packages("remotes")
remotes::install_github("benjaminschlegel/brant")

You might need to install Rtools (for Windows) or XCode (for Mac OS) to install the package from GitHub.