The pblm package: semiparametric regression for bivariate categorical responses in R

We present an R package to fit semiparametric regression models for two categorical responses. It works for both nominal and ordered responses and several types of logits can be specified. Proportional, non-proportional and partial proportional odds models can be fitted, with marginal and association parameters estimated in a parametric or semiparametric way, via penalized maximum likelihood estimation. An application to show the potential of the package is carried out on a data set of Italian university students.