Please use this identifier to cite or link to this item: http://hdl.handle.net/10419/111216
Authors: 
Baetschmann, Gregori
Winkelmann, Rainer
Year of Publication: 
2014
Series/Report no.: 
Working Paper Series, University of Zurich, Department of Economics 151
Abstract: 
Excess zeros are encountered in many empirical count data applications. We provide a new explanation of extra zeros, related to the underlying stochastic process that generates events. The process has two rates, a lower rate until the first event, and a higher one thereafter. We derive the corresponding distribution of the number of events during a fixed period and extend it to account for observed and unobserved heterogeneity. An application to the socio-economic determinants of the individual number of doctor visits in Germany illustrates the usefulness of the new approach.
Subjects: 
excess zeros
Poisson process
exposure
hurdle model
JEL: 
C25
I10
Persistent Identifier of the first edition: 
Document Type: 
Working Paper

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