In this dissertation I study the labor market behavior of sciences and engineering (S&E) doctorates trained and employed in the US. The first essay is an empirical study of task-to-task transitions based on the Survey of Doctorate Recipients (1973-2001). It first assesses the relevance of the careers of doctorates to S&E in general, and research and development (R&D) in particular. Second, it evaluates the participation rates and mobility patterns of doctorates in careers of different types using a transition model with independent competing risks. The second essay extends the empirical framework described above and specifies a dynamic model of occupational choices with symmetric learning about one of the task- specific abilities and dependence on past performance to explain the empirical career patterns described in the first essay. The predictions of the model are used to evaluate the effects of two counterfactual experiments on the supply of research skill. The third essay studies geographic choices for first employment of doctorates using the Survey of Earned Doctorates (SED) 1957-2005. Decisions of Americans, Canadians, and third country nationals to stay in the US after their PhD versus moving to Canada are compared. Individual characteristics and differences in political and economic conditions and career opportunities in the US versus Canada are evaluated to explain the observed differences in the choice of location. / Thesis (Ph.D, Economics) -- Queen's University, 2009-08-31 11:33:27.809