Journal of Political Economy197583(6), 1113-1144open access
This paper develops a theoretical example of a business cycle, that is, a model economy in which real output undergoes serially correlated movements about trend which are not explainable by movements in the availability of factors of production. The mechanism generating these movements involves unsystematic monetary-fiscal shocks, the effects of which are distributed through time due to information lags and an accelerator effect. Associated with these output movements are procyclical movements in prices, procyclical movements in the share of output devoted to investment, and, in a somewhat limited sense, procyclical movements in nominal rates of interest.
Journal of Political Economy2004112(S1), S29-S59open access
This paper is a theoretical study of rural‐urban migration—urbanization—as it has occurred in many low‐income economies in the postwar period. This process is viewed as a transfer of labor from a traditional, land‐intensive technology to a human capital–intensive technology with an unending potential for growth. The model emphasizes the role of cities as places in which new immigrants can accumulate the skills required by modern production technologies.
In this paper we analyze an aggregative general equilibriiri model in which the use of money is motivated by a cash-in-advance constraint, applied to purchases of a subset of consumption goods. The system is subject to both real and nxnetary shocks, which are economy-wide and observed by all. We develop methods for verifying the existence of, characterizing, and explicitly calculating equilibria. A main result of the analysis is that current money growth affects the current real allocation only insofar as it affects expectations about future money growth, i.e., only through its value as a signal.
Journal of Political Economy2014122(1), 1-51open access
We analyze a model economy with many agents, each with a different productivity level. Agents divide their time between two activities: producing goods with the production-related knowledge they already have and interacting with others in search of new, productivity-increasing ideas. These choices jointly determine the economy’s current production level and its rate of learning and real growth. We construct the balanced growth path for this economy. We also study the allocation chosen by an idealized planner who takes into account and internalizes the external benefits of search. Finally, we provide three examples of alternative learning technologies and show that the properties of equilibrium allocations are quite sensitive to two of these variations.
Journal of Political Economy2007115(2), 171-199open access
This paper develops a model of a monetary economy in which individual firms are subject to idiosyncratic productivity shocks as well as general inflation. Sellers can change price only by incurring a real “menu cost.†We calibrate this cost and the variance and autocorrelation of the idiosyncratic shock using a new U.S. data set of individual prices due to Klenow and Kryvtsov. The prediction of the calibrated model for the effects of high inflation on the frequency of price changes accords well with international evidence from various studies. The model is also used to conduct numerical experiments on the economy’s response to various shocks. In none of the simulations we conducted did monetary shocks induce large or persistent real responses.