Research Database

We present a model of vintage human capital. The economy exhibits exogenous deterministic technological change. Technology requires skills that are specific to the vintage. A stationary competitive equilibrium is defined and shown to exist and be unique, as well as Pareto optimal. The stationary equilibrium is characterized by an endogenous distribution of skilled workers across vintages. The distribution is shown to be single peaked and there is diffusion of technology in the sense that there is a lag between the time when a technology appears and the peak of its usage. An increase in the rate of exogenous technological change shifts the distribution of human capital to more recent vintages and increases the relative wage of the unskilled workers in each vintage.

The consequences of a straightforward monetary targeting scheme are examined for a simple dynamic macro model. The notion of "targeting" used below is the strategic one introduced by Rogoff (1985). Numerical simulations are used to demonstrate that for the model under consideration, monetary targeting is likely to lead to a deterioration of policy performance. These examples cast doubt upon the general efficacy of simple targeting schemes in dynamic rational expectations models.

This paper studies the relationship between the existence and optimality of a monetary steady-state and the nonoptimality of nonmonetary steady-states. We construct a sequence of stationary overlapping generations economies with longer and longer lived generations in which all agents maximize a discounted sum of utilities with a common discount rate. Under some assumptions the following result is established: If the discount rate is greater (less) than the population growth rate, then eventually every nonmonetary steady-state is optimal (non-optimal) and a monetary steady-state does not exist (exists and is optimal).