Research Database

ln environments with private information and spatial separation, the ability of agents to establish mutually beneficial arrangements can be limited by their ability to communicate contemporary dealings and histories of past dealings. Indeed, with the extension of some recent work in contract theory and mechanism design, this paper argues that location or person-specific assignment systems, portable object record-keeping systems, written message systems, and telecommunication systems can be viewed as communication systems which are successively more complete in this sense. An attempt is made also to match these various communication systems with systems in use in historical primitive, and/or contemporary societies and to interpret these communication systems as financial structures.

This paper reports some empirical evidence on the relation between the expected real interest rate and monetary aggregates in postwar U.S. data. We find some evidence against the hypothesis, implied by the Real Business Cycle model of Litterman and Weiss (1985), that the expected real interest rate follows a univariate autoregressive process, not Granger-caused by monetary aggregates. Our findings, however, are consistent with a more general bivariate model--suggested by what Barro (1987, Chapter 5) refers to as "the basic market-clearing model"--in which the real rate depends on its own lagged values and on lagged output. Taking this bivariate model as our null hypothesis, we find no evidence that money-stock changes have a significant liquidity effect on the expected real interest rate.

The new classical view that macroeconomic fluctuations can be modeled as an equilibrium system perturbed by transitory monetary disturbances has been challenged in recent years by another equilibrium view of fluctuations, the so-called real business cycle theory. In this latter framework, shocks to the production function induce both intertemporal substitution of labor supply and permanent shifts in the stochastic trend of output. Monetary shocks, on the other hand, play only a minor role in this view of the cycle. Much of the empirical support for the real business cycle view of fluctuations is based on a re-examination of traditional methods for detrending economic time series. The issues raised by the real business cycle theorists are not new; indeed, they go back at least to the NBER's first business cycle studies. However, the real business cycle theorists attach a radical economic interpretation to what, on the surface, appears to be a purely technical note on the proper method for detrending economic data. This paper reviews the debate over stochastic trends, discusses the economic implications of the real business cycle interpretation of stochastic trend models, and weighs the time series evidence for some of the stronger claims made by real business cycle theorists. We conclude that, while this literature raises real and useful questions about the interpretation of observed fluctuations, the new classical view of the cycle is not ruled out by the data.

This paper presents a model of growth through technical progress. The nature and scope of what is learned is derived from a set of axioms, and optimal search behavior by agents is then analyzed. Agents can search intensively or extensively. Intensive search explores a technology in greater depth, while extensive search yields new technologies. Agents alternate between these two modes of search. The economy grows forever and the growth rate is bounded away from zero. The growth rate is on average higher during periods of intensive search than during periods of extensive search. Epochs of higher growth are initiated by discoveries that call for further intensive exploration. This mechanism is reminiscent of the process described by Schumpeter as causing long-wave business cycles. Serial correlation properties of output and growth stem from the presence of intensive rather than extensive search. The two key parameters are technological opportunity and the cost of the extensive search.

The objective of this paper is to investigate whether, in a Sidrauski type model with uncertainty, welfare maximization calls for following the famous "Chicago Rule". This question will be answered in the affirmative in this paper, i.e. social welfare optimization calls for a zero nominal interest rate on one-period bonds. The zero nominal interest rate, however, does not imply in an uncertain world that there is no systematic difference between the expected rate of deflation and the rate of time preference in an economy without growth. The magnitude of this difference turns out to be small, however. Numerical welfare comparisons are made between the optimal policy and policies in which the growth rate of money is fixed. The optimal policy requires that the monetary authorities react every period to the available information and they choose a growth level of the money stock that will set the interest rate equal to zero. If we compare the time paths of the real variables under the optimal policy with the time paths if the money supply decreases at a rate equal to the rate of time preference, then we see hardly any differences. The price dynamics can be very different, however. The paper also investigates the issue of superneutrality and finds that the quantitative deviations from superneutrality are substantial if a model with a shopping time technology is used. The neo-classical models in this paper are solved numerically using a technique developed in Marcet (1988).

We consider a model of international sovereign debt where repayment is enforced because defaulting nations lose their reputation and consequently, are excluded from international capital markets. Underlying the analysis of reputation is the hypothesis that borrowing countries have different, unobservable, attitudes towards the future. Some regimes are relatively myopic, while others are willing to make sacrifices to preserve their access to debt markets. Nations' preferences, while unobservable, are not fixed but evolve over time according to a Markov process. We make two main points. First we argue that in models of sovereign debt the length of the punishment interval that follows a default should be based on economic factors rather than being chosen arbitrarily. In our model, the length of the most natural punishment interval depends primarily on the preference parameters. Second, we point out that there is a more direct way for governments to regain their reputation. By offering to partially repay loans in default, a government can signal its reliability. This type of signaling can cause punishment interval equilibria to break down. We examine the historical record on lending resumption to argue that in almost all cases, some kind of partial repayment was made.

We construct a model of the product cycle featuring endogenous innovation and endogenous technology transfer. Competitive entrepreneurs in the North expend resources to bring out new products whenever expected present discounted value of future oligopoly profits exceeds current product development costs. Each Northern oligopolist continuously faces the risk that its product will be copied by a Southern imitator, at which time its profit stream will come to an end. In the South, competitive entrepreneurs may devote resources to learning the production processes that have been developed in the North. There too, costs (of reverse engineering) must be covered by a stream of operating profits. We study the determinants of the long-run rate of growth of the world economy, and the long-run rate of technological diffusion. We also provide an analysis of the effects of exogenous events and of public policy on relative wage rates in the two regions.

A cash-in-advance constraint on consumption is incorporated into a standard model of consumption and capital accumulation. Monetary policy consists of lump-sum cash transfers. Methods are developed for establishing the existence and uniqueness of an equilibrium and for explicitly constructing this equilibrium. The model economy's dependence on monetary policy is explored.

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.