Voluntary and Involuntary Labor Mobility: A Bivariate Poisson Regression Approach*

The study introduces a distinction between two types of labor mobility: direct job to job changes (which are assumed to be voluntary) and job changes after experiencing an unemployment spell (assumed to be involuntary). Exploiting the close relationship between those two phenomena we adopt a bivariate regression framework for our empirical analysis of data on male individuals in the German labor market. To account for the non-negative and discrete nature of the two counts of job changes in a ten year interval a new econometric model is proposed: the bivariate Poisson regression proves to be superior to the univariate specification. Further, the empirical content of distinguishing between two types of mobility is subject to a test, and, in fact, supported by the data: The hypothesis that both measures are observationally equivalent can be rejected. Voluntary and Involuntary Labor Mobility: A Bivariate Poisson Regression Approach* Robert C. Jung University of Konstanz Rainer Winkelmann SELAPO, University of Munich SUMMARY The study introduces a distinction between two types of labor mobility: Direct job to job changes (which are assumed to be voluntary) and job changes after experiencing an unemployment spell (assumed to be involuntary). Exploiting the close relationship between those two phenomena we adopt a bivariate regression framework for our empirical analysis of data on male individuals in the German labor market. To account for the non-negative and discrete nature of the two counts of job changes in a ten year interval a new econometric model is proposed: the bivariate Poisson regression proves to be superior to the univariate specification. Further, the empirical content of distinguishing between two types of mobility is subject to a test, and, in fact, supported by the data: The hypothesis that both measures are observationally equivalent can be rejected. JEL codes: C25, J24, J60 * Valuable comments by Wolfgang Franz, Gerd Ronning, Christoph M. Schmidt as well as two anonymous referees are gratefully acknowledged.