This paper explores the robustness of the essential economic conclusions of the Roy model of self-selection and income inequality to relaxation of its normality assumptions. A log concave version of the model reproduces most of the main results. Log convex cases offer counterexamples. The...

This paper considers the formulation, estimation, and evaluation of semiparametric multistates duration models with time-varying regressors and unobservables correlated over spells. The authors' models are applied to test a dynamic version of the neoclassical theory of fertility. Using Swedish...