Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper discusses the specification and estimation of seemingly unrelated multivariate count data models. A new model with negative binomial marginals is proposed. In contrast to a previous model based on the multivariate Poisson distribution, the new model allows for over‐dispersion, a phenomenon that is frequently encountered in economic count data. Semi‐parametric estimation is possible if some of the assumption of the fully specified model are violated.