I have some count data (0 - 1 at each time point for each test subject) that I would like to model. Since the 1's are rather sparse, the Poisson distribution comes to mind but I would also consider the binomial. The data are censored as the data come from a clinical trial and subjects were able to leave the study and some were therefore lost to follow-up. I am aware of the capabilities of lme( ) and nlme( ) through the excellent book by Pinheiro and Bates, but am at a loss as to what to do with these count data. Ideally, I would like to compare the placebo and treatment groups in a meaningful way. Any input would be greatly appreciated. Thanks, Greg __________________________________