This paper investigates the effect of (potential) market size on entry of new drugs and pharmaceutical innovation. Focusing on exogenous changes driven by U. S. demographic trends, we find a large effect of potential market size on the entry of nongeneric drugs and new molecular entities. These effects are generally robust to controlling for a variety of supply-side factors and changes in the technology of pharmaceutical research.

We provide a new and more complete analysis of the origins of the Dust Bowl of the 1930s, one of the most severe environmental crises in North America in the twentieth century. Severe drought and wind erosion hit the Great Plains in 1930 and lasted through 1940. There were similar droughts in the 1950s and 1970s, but no comparable level of wind erosion. We explain why. The prevalence of small farms in the 1930s limited private solutions for controlling the downwind externalities associated with wind erosion. Drifting sand from unprotected fields damaged neighboring farms. Small farmers cultivated more of their land and were less likely to invest in erosion control than larger farmers. Soil conservation districts, established by the government after 1937, helped coordinate erosion control. This “unitized” solution for collective action is similar to that used in other natural resource/environmental settings.

have provided us with a wealth of information about the newest products of U.S. Ph.D. programs. Among the notable facts are the continuing decline in the share of U.S. natives among these new graduates, their continued success at landing academic and other professional jobs, and their high level of professional fulfillment, in terms of both job satisfaction and outcomes measuring up to expectations. There are also a variety of intriguing results. For example, (from their table 5) students completing the top Ph.D. programs were younger, less likely to be married, and more likely to be foreign than those in the overall sample. Perhaps most disturbing, (from their table 6) median starting full-time academic salaries were lowest in public economics, a result that cannot be accounted for in salary regressions with other covariates. This clearly is an inversion of the appropriate ranking. In my comments, I will focus on two selected aspects of Ph.D. programs and the Ph.D. job market.

We show that analysts from sell‐side firms generally recommend “glamour” (i.e., positive momentum, high growth, high volume, and relatively expensive) stocks. Naïve adherence to these recommendations can be costly, because the level of the consensus recommendation adds value only among stocks with favorable quantitative characteristics (i.e., value stocks and positive momentum stocks). In fact, among stocks with unfavorable quantitative characteristics, higher consensus recommendations are associated with worse subsequent returns. In contrast, we find that the quarterly change in consensus recommendations is a robust return predictor that appears to contain information orthogonal to a large range of other predictive variables.