In this study, earnings are decomposed in order to measure the effects due to individual characteristics and to unobserved heterogeneity. These effects are shown to work in opposite directions, complicating the effect of earnings on migration. The use of aggregate earnings masks the two separate...

This paper shows that the frequency of migration can be best modeled by a zero-inflated Poisson process, because it takes into account the overwhelming presence of zeros (nonmigrants) in the data. A failure to do so can cause the coefficients to be biased and also result in poor prediction. The...