Simple search models have equilibria where some agents accept money and others do not. We argue such equilibria should not be taken seriously. This is unfortunate if one wants a model with partial acceptability. We introduce heterogeneous agents and show partial acceptability arises naturally...

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...

We study the long-run relation between money, measured by inflation or interest rates, and unemployment. We first document in the data a positive relation between these variables at low frequencies. We then develop a framework where unemployment and money are both modeled using microfoundations...

This essay articulates the principles and practices of New Monetarism, our label for a recent body of work on money, banking, payments, and asset markets. We first discuss methodological issues distinguishing our approach from others: it has something in common with Old Monetarism, but there are...

We study a market where innovators, who are good at coming up with ideas, can sell them to entrepreneurs, who might be better at implementing them. The market is decentralized, with random matching and bargaining. Ideas are characterized by five salient features: they are indivisible; partially...