Research Database

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.

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.

We incorporate the consumption-ability relationship of static "efficiency wage" models into a dynamic general equilibrium model. We show that for many aggregate land stocks, there is a continuum of unemployment rates which could persist indefinitely as part of a stationary equilibrium. For many of these aggregate land stocks, both unemployment and full employment are distrinct possibilities. Broadly speaking, more unemployment corresponds to more undernourishment and more inequality in land distribution. Thus our results suggest that the market mechanism is less efficacious than land reform in reducing unemployment and undernourishment.