The essential function of money is its role as a medium of exchange. The authors formalize this idea using a search-theoretic equilibrium model of the exchange process that captures the "double coincidence of wants problem" with pure barter. One advantage of the framework described here is that...

How important is monopolistic competition to an understanding of the effects of aggregate demand on output? The authors ask this question at three levels. Can monopolistic competition, by itself, explain why aggregate demand affects output? Can it, together with other imperfections, generate...

We study the long-run relation between money (inflation or interest rates) and unemployment. We document positive relationships between these variables at low frequencies. We develop a framework where money and unemployment are modeled using explicit microfoundations, providing a unified theory...

The authors develop a model of production and exchange with uncertainty concerning the quality of commodities and study the role of fiat money in ameliorating frictions caused by private information. The model is specified so that, without private information, only high-quality commodities are...

The authors document and attempt to explain the observation that automobile insurance premiums vary dramatically across cities. The authors argue that high premiums can be attributed, at least in part, to large numbers of uninsured motorists in some markets, while uninsured motorists can be...