Unobserved Heterogeneity in Multi-Spell Discrete Time Duration Models

This paper considers the estimation of discrete time duration models. We highlight the enhance identification opportunities embedded in multiple spell data to separately identify the effect of duration dependence and individual time invariant unobserved heterogeneity. We consider two types of models: (i) random effects models specifying a mass point distribution for the unobserved heterogeneity; and (ii) fixed effects models in which the distribution of the effects is left unrestricted. The availability of multiple spell data allows us to consider this type of models, in the spirit of fixed effects discrete choice panel data models. We study the finite sample properties of different estimators for previous models by means of Monte Carlo simulations. Finally, as an empirical illustration, we estimate unemployment duration models using Spanish administrative data with information on the entire labor history of the individuals.