We compare free trade reached through expanding regional trading blocs to free trade accomplished by multilateral negotiation. With sunk costs, the outcomes are different. Trade in an imperfectly competitive good flows disproportionately more between the original members of a regional agreement even after free trade is reached. They secure a higher welfare level from regionalism than from free trade achieved multilaterally; nonmembers, however, reach a lower welfare level. A surprising result is that world welfare during free trade is greater when it is achieved by the regional path. We conclude with some empirical evidence from the European Union that is consistent with the model.

This study investigates the relationship between economic conditions and health. Total mortality and eight of the ten sources of fatalities examined are shown to exhibit a procyclical fluctuation, with suicides representing an important exception. The variations are largest for those causes and age groups where behavioral responses are most plausible, and there is some evidence that the unfavorable health effects of temporary upturns are partially or fully offset if the economic growth is long-lasting. An accompanying analysis of micro data indicates that smoking and obesity increase when the economy strengthens, whereas physical activity is reduced and diet becomes less healthy.

I identify the effects of class size on student achievement using longitudinal variation in the population associated with each grade in 649 elementary schools. I use variation in class size driven by idiosyncratic variation in the population. I also use discrete jumps in class size that occur when a small change in enrollment triggers a maximum or minimum class size rule. The estimates indicate that class size does not have a statistically significant effect on student achievement. I rule out even modest effects (2 to 4 percent of a standard deviation in scores for a 10 percent reduction in class size).

A recent paper in this Journal by Kaplan and Zingales reexamines a subset of firms from work of Fazzari, Hubbard, and Petersen and criticizes the usefulness of investment-cash flow sensitivities for detecting financing constraints. We show that the Kaplan and Zingales theoretical model fails to capture the approach employed in the literature and thus does not provide an effective critique. Moreover, we describe why their empirical classification system is flawed in identifYing both whether firms are constrained and the relative degree of constraints across firm groups. We conclude that their results do not support their conclusions about the usefulness of investment-cash flow sensitivities.