In this paper I show that the conditional fixed effects negative binomial model for count panel data does not control for individual fixed effects unless a very specific set of assumptions are met. I also propose a score test to verify whether these assumptions are met.

This paper estimates the employer-size wage effect on returns to unobservable skills and measured human capital variables using a novel methodology that allows us to estimate a high number of interactions between unobserved effects and firm size. Our results show that in large firms, returns to...

In Portugal duration of benefits is exclusively age determined while replacement rates are essentially uniform. We exploit differences in potential maximum duration of benefits for nearly matched pairs of individuals to determine the effects of benefit duration on job finding.