Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2006."June 2006."Includes bibliographical references (p. 88-94).This thesis is a collection of three essays on labor economics from a macroeconomic prospective. Chapter 1 discusses imperfect information, self-selection and the market for higher education. It explores how the steady trends in increased tuition costs, college enrollment and returns to education might be related to the quality of college graduates. The model shows that the signaling role of education might be an important, yet largely neglected ingredient in these recent changes. In a special signaling model, workers face the same costs, but can expect different returns from college. Allocation of abil...