In this article, we describe twopm, a command for fitting two-part models for mixed discrete-continuous outcomes. In the two-part model, a binary choice model is fit for the probability of observing a positive-versus-zero outcome. Then, conditional on a positive outcome, an appropriate...

I describe a command that simultaneously solves the extended es- timating equations estimator for parameters in the link and variance functions along with those of the linear predictor in a generalized linear model. The method addresses difficulties in choosing the correct link and variance...