The randomly assigned risk of induction generated by the draft lottery is used to construct estimates of the effect of veteran status on civilian earnings. These estimates are not biased by the fact that certain types of men are more likely than others to service in the military. Social Security administrative records indicate that, in the early 1980s, long after their service in Vietnam had ended, the earnings of white veterans were approximately 15 percent less than the earnings of comparable nonveterans.

In the absence of significant news, hedging strategies were blamed for the stock market crash of October 1987; but traditional models cannot explain how a relatively small amount of selling could cause so large a price drop. The authors develop a rational expectations model in which prices play an important role in shaping expectations; markets are much less liquid in their model than in traditional models. Discontinuities (or "crashes") can occur even with relatively little hedging. The model is consistent with theories as disparate as Keynes' "beauty contest" insights and Thom's "catastrophe" analysis and suggests means to reduce volatility.

A social exchange approach to voluntary cooperation is developed on the assumption that voluntary cooperative behavior is motivated by social approval, which is conceptualized as an emotional activity. The associated unique Nash equilibrium may have attractive welfare properties and provides an understanding of spontaneous norm emergence. Furthermore, the opening of a market or government intervention for the collective good is shown to affect voluntary cooperation negatively.

The authors study natural selection of preferences using a golden-age model with endogenous population. In equilibrium, all agents have preferences with maximum biological fitness, given resource constraints, and total population is the maximum the environment can sustain. Naturally selected agents follow the golden rule, acting as if they maximize the undiscounted sum of per-capita felicities of current and future generations. Selected preferences and, hence, work, saving, consumption, and population density vary predictably with environmental differences

This paper develops a model of product patents in which the patent changes the nature of market entry behavior rather than preventing entry entirely. The model incorporates three levels of action, namely, the innovator's patenting decision, the potential entrant's location decision, and possible court action. The analysis demonstrates how the characteristics of the patents system and the enforcement framework can influence rivals' variety choices and, thus, the market equilibrium. It also considers how the system can, in principle, be adjusted to improve social welfare

A large importer who places relatively greater weight on future than current oil consumption will import less oil in the future than if it were able to commit itself in advance to future tariffs, and may find itself worse off than if it were unable to impose tariffs at all. Futures markets and storage modify these adverse effects and may avoid the problem of dynamic inconsistency.

It is often argued that the same expenditures on military procurement would produce a more effective defense if larger numbers of less sophisticated (and thus cheaper) weapons were purchased. This paper shows that such a result can occur even if the military derives no private consumption value from technically sophisticated weapons. Rather, the organization of the decision-making process itself can produce this result. This suggests some possible solutions through organizing decision-making in a different fashion

This paper examines the effects of the Federal Trade Commission's Advertising Substantiation Program, developed in the early 1970s. This program coupled changes in the legal definition of deception with more vigorous FTC enforcement. The authors analyze changes in advertising intensity, media choice, media wealth, and the progress of new entrants. The evidence suggests that adoption of substantiation requirements increased the credibility of advertising