I have a pre-post treatment and comparison quasi-experiment for business foundings and failures.I have been able to use xtnbreg or xtgee in Stata to estimate this regression, but I would like to be able to do it in R. It would also be nice to have zero-inflated models. When I consulted experts last year, the options included cross sectional GEE in R using Poisson or quasi-poisson. Or to use glm.nb cross-sectional analysis. There is a pglm package, but it does not have the GEE population averaged model. As far as I can tell, neither gee nor geepack take the negative binomial family from the MASS package. However, I see a new package geeM and it looks like it might work. Does anyone have experience using it?