Research Database

This paper develops a new method for approximating dynamic competitive equilibria in economies in which competitive equilibrium is not necessarily Pareto optimal. The method involves finding approximate equilibrium policy functions by iterating on the stochastic Euler equations which characterize the economy's equilibrium. Two applications are presented: the stochastic growth model of Brock and Mirman (1971) modified to allow distortionary taxation, and a model of inflation and capital accumulation based on Stockman (1981). The computational speed and accuracy of this approach suggests that it may be a feasible method for studying suboptimal economies with large state spaces.

Across developing countries, capital market inefficiencies tend to decrease and external borrowing tends to sharply increase as national wealth rises. We construct a simple model of intertemporal trade under asymmetric information which provides a coherent explanation of both these phenomenon, without appealing to imperfect capital mobility. The model can be applied to a number of policy issues in LDC lending, including the debt overhang problem, and the impact of government guarantees of private debt to foreign creditors. In the two-country general equilibrium version of the model, an increase in wealth in the rich country can induce a decline in investment in the poor country via a "siphoning effect". Finally, we present some new empirical evidence regarding the link between LDC borrowing and per capita income.

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 under general conditions there is a lag between the time when a technology appears and the peak of its usage, what is known as diffusion. An increase in the rate of exogenous technological charge shirts the distribution of human capital to more recent vintages and increases the relative wage of the unskilled workers in each vintage.

This paper considers the relationship between total private factor productivity and stock and flow government expenditure variables. The empirical results indicate that (i) the nonmilitary public capital stock is dramatically more important in determining productivity than is either the flow of nonmilitary or military spending, (ii) military capital is not productive, and (iii) the public stock of structures--especially a "core" infrastructure of streets, highways, sewers, and water systems--has more explanatory power for productivity than does the stock of equipment. The paper also suggests an important role for the net public capital stock in the "productivity slowdown" of the last fifteen years.