We present a restriction on the domain of individual preferences that is both necessary and sufficient for the existence of a social choice rule that is continuous, anonymous, and respects unanimity. The restriction is that the space of preferences be contractible. Contractibility admits a...

Oil price behavior has changed dramatically in the last twenty years. These changes can be explained rather simply in terms of the delayed responses of supply and demand to prices, and in terms of changes in the rate of discovery of reserves. This analysis can be used to forecast possible future...

An economy faces an unknown individual risk, such as the health effects of a recently discovered environmental hazard. Opinions may be widely different about the distribution of risks across the population. We study financial markets that suffice to reach efficient allocations in this situation....

It is widely recognized that the value of environmental assets such as biodiversity, unique locations and the atmosphere may be hard to quantify. In particular, option values, quasi-option values and non-use values have been the subject of extensive discussion. We propose here an evaluation of...

An economy faces an unknown individual risk, such as the health effects of recently discovered environmental hazard. Opinions may be widely different about the distribution of risks across the population. We study financial markets that suffice to reach efficient allocations in this situation....

Consider an exchange economy with multiple competitive equilibria. Agents know the set of equilibria, but not which will be selected. To insure against unfavorable equilibrium outcomes, they trade on markets for commodities contingent on the equilibrium price vector. Such price-contingent...

We study the risks associated with the prospect of global climate change, and review the mechanisms available for their efficient allocation in market economies. Risks in this field are typically unknown and often unknowable ex ante; their probabilities are endogenous and determined by economic...

Our concern in this paper is to analyze the optimal long-run pricing policies of oil-exporting countries. These might be described briefly as the policies which best meet their objectives, subject to the various limitations imposed on them by the realities of world economic forces.

Although American business leaders do not like protectionism, more and more of them are concluding that too many countries are stacking the deck against American competitors. The severe recession of 1980-83 and its lingering effects in certain regions and business sectors; unemployment stuck at...