Economists' productivity over their careers and as measured by publication in leading journals declines very sharply with age. There is no difference by age in the probability that an article submitted to a leading journal will be accepted. Rates of declining productivity are no greater among the very top publishers than among others, and the probability of acceptance is increasingly related to the author's quality rather than the author's age.

Emissions of carbon dioxide from the combustion of fossil fuels, which may contribute to long-term climate change, are projected through 2050 using reduced-form models estimated with national-level panel data for the period of 1950–1990. Using the same set of income and population growth assumptions as the Intergovernmental Panel on Climate Change (IPCC), we find that the IPCC's widely used emissions growth projections exhibit significant and substantial departures from the implications of historical experience. Our model employs a flexible form for income effects, along with fixed time and country effects, and we handle forecast uncertainty explicitly. We find clear evidence of an “inverse U” relation with a within-sample peak between carbon dioxide emissions (and energy use) per capita and per-capita income.

This study used a 1976–1992 panel data set to test whether farm machinery investors face finance constraints. Tests were based on fundamental q investment equations in which cash flow was added as an additional explanatory variable. Results indicated that (1) credit constraints were generally not a problem during the 1970s boom, (2) credit constraints became a problem during the 1980s and early 1990s because of tighter credit and/or more conservative financial managerial styles, (3) the investment-cash flow relationships of low-debt and older-operator farms were not significantly affected by farm business cycles, and (4) the investment-cash flow relationships of high-debt and young-operator farms were affected strongly by business cycles. Debt level was the strongest determinant of credit constraints; asset size and operator age were less important.

A feature of U.S. postwar business cycle experience that is by now widely documented is the tendency of the spread between the respective interest rates on commercial paper and Treasury bills to widen shortly before the onset of recessions. By contrast, the paper—bill spread did not anticipate the 1990–1991 recession. Empirical work presented in this paper supports two (not mutually exclusive) explanations for this departure from past experience. First, at least part of the paper—bill spread's predictive content with respect to business cycle fluctuations stems from its role as an indicator of monetary policy, but the 1990–1991 recession was unusual in postwar U.S. experience in not being immediately precipitated by tight monetary policy. Second, movements of the spread during the few years just prior to the 1990–1991 recession were strongly influenced by changes in the relative quantities of commercial paper, bank CDs, and Treasury bills that occurred for reasons unrelated to the business cycle. This latter finding in particular sheds light on the important role of imperfect substitutability of different short-term debt instruments in investors' portfolios, and highlights the burdens associated with using relative interest rate relationships as business cycle indicators.

This study provides new evidence of the importance of financing constraints for explaining the dramatic cycles in inventory investment. We compare the empirical performance of different financial variables (coverage ratio, cash stocks, and cash flow) used in previous research to test for the presence of financing constraints. The comparison is undertaken in a common framework with an identical sample and high-frequency (quarterly) firm panel data. Cash flow is much more successful than cash stocks or coverage in explaining the facts about inventory investment across firm size, different inventory cycles, and different manufacturing sectors.