Recent studies suggest that the conditional CAPM might hold, period-by-period, and that time-varying betas can explain the failures of the simple, unconditional CAPM. We argue, however, that significant departures from the unconditional CAPM would require implausibly large time-variation in...

In this paper, we argue that campaign contributions are not a form of policy-buying, but are rather a form of political participation and consumption. We summarize the data on campaign spending, and show through our descriptive statistics and our econometric analysis that individuals, not...

We look at a principal-agent model in which the agent has to perform an action, the difficulty of which is better known ex interim than ex ante. We compare two contracting regimes; one with commitment to an ex ante negotiated contract, and one with an ex interim negotiated contract. The ex ante...

"A revised version to appear in K.J. Arrow and M.D. Intriligator (eds.), Handbook of mathematical economics. Amsterdam: North-Holland Publishing Company (1978)."

We consider a single-product inventory system that serves multiple demand classes, which differ in their shortage costs or service level requirements. We assume a critical-level control policy, and show the equivalence between this inventory system and a serial inventory system. Based on this...