Get access

CONSISTENT ESTIMATION OF ZERO-INFLATED COUNT MODELS

Authors


Correspondence to: Department of Economics, University of Zurich, Zürichbergstr. 14, CH-8032, Zürich, Switzerland. E-mail: rainer.winkelmann@econ.uzh.ch

ABSTRACT

Applications of zero-inflated count data models have proliferated in health economics. However, zero-inflated Poisson or zero-inflated negative binomial maximum likelihood estimators are not robust to misspecification. This article proposes Poisson quasi-likelihood estimators as an alternative. These estimators are consistent in the presence of excess zeros without having to specify the full distribution. The advantages of the Poisson quasi-likelihood approach are illustrated in a series of Monte Carlo simulations and in an application to the demand for health services. Copyright © 2012 John Wiley & Sons, Ltd.

Get access to the full text of this article

Ancillary