In a model of evolution driven by conflict between societies more powerful states have an advantage. When the influence of outsiders is small we show that this results in a tendency to hegemony. In a simple example in which institutions differ in their "exclusiveness" we find that these...

Intellectual property (IP) protection involves a trade-off between the undesirability of monopoly and the desirable encouragement of creation and innovation. Optimal policy depends on the quantitative strength of these two forces. We give a quantitative assessment of current IP policies. We...

Committees improve decisions by pooling independent information of members, but promote manipulation, obfuscation, and exaggeration of private evidence when members have conflicting preferences. We study how self-interest mediates these conflicting forces. When members' preferences differ, no...

The major theme of this article is that the interpretation of contracts -- their possible amplification, correction, and modification by adjudicators -- is in the interests of contracting parties. The general reasons are (a) that interpretation may improve on otherwise imperfect contracts; and...

Individuals involved in basic research, like other workers, respond to incentives. Funding agencies provide implicit incentives when they specify the rules by which awards are made. The following analysis is an exercise in understanding incentives at an applied level. Specific rules are examined...

This essay reviews progress in empirical economics since Leamer's (1983) critique. Leamer highlighted the benefits of sensitivity analysis, a procedure in which researchers show how their results change with changes in specification or functional form. Sensitivity analysis has had a salutary but...

One approach to urban areas emphasizes the existence of certain immutable relationships, such as Zipf's or Gibrat's Law. An alternative view is that urban change reflects individual responses to changing tastes or technologies. This paper examines almost 200 years of regional change in the U.S....

More advanced technologies demand higher degrees of specialization - and longer chains of production connecting raw inputs to final outputs. Longer production chains are subject to a "weakest link" effect: they are more fragile and more prone to failure. Optimal chain length is determined by the...

We test the effectiveness of self-help peer groups as a commitment device for precautionary savings, through two randomized field experiments among 2,687 microentrepreneurs in Chile. The first experiment finds that self-help peer groups are a powerful tool to increase savings (the number of...

There are persistent differences in self-reported subjective well-being across U.S. metropolitan areas, and residents of declining cities appear less happy than other Americans. Newer residents of these cities appear to be as unhappy as longer term residents, and yet some people continue to move...