Hi

My dependent variable is the number of policies that a company has adopted in the given year. It ranges from 0 to 20 (maximum). In my sample, there are a lot of companies that have never adopted a related policy. Data is structured as an unbalanced panel. Independent variables are mostly continuous but some are dummies.

I am considering a negative binomial regression (using xtnbreg command) or a zero-inflated model. Is it not good to use xtnbreg , fe? Is it better to use xtnbreg , pa? What is the right command to run a zero-inflated model for panel data?