Seemingly unrelated negative binomial regression

This paper discusses the specification and estimation of seemingly unrelate d multivariate count data models. A new model with negative binomial margin als is proposed. In contrast to a previous model based on the multivariate Poisson distribution, the new model allows for over-dispersion, a phenomeno n that is frequently encountered in economic count data. Semi-parametric es timation is possible if some of the assumption of the fully specified model are violated.