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Log-concave probability and its applications

Summary. In many applications, assumptions about the log-concavity of a probability distribution allow just enough special structure to yield a workable theory. This paper catalogs a series of theorems relating log-concavity and/or log-convexity of probability density functions, distribution functions, reliability functions, and their integrals. We list a large number of commonly-used probability distributions and report the log-concavity or log-convexity of their density functions and their integrals. We also discuss a variety of applications of log-concavity that have appeared in the literature.Received: 31 December 2003, Revised: 22 March 2004, JEL Classification Numbers: C40, D40, D80. Correspondence to: Ted BergstromWe thank Ken Binmore and Larry Samuelson for encouragement and suggestments.     

Neighborhood Demographics and the Distribution of Hazardous Waste Risks: An Instrumental Variables Estimation

This paper examines whether the marginal price of risk reduction varies by the demographic characteristics of neighborhoods. Using an instrumental-variables approach to control for the two-way relationship between housing prices and environmental risk, the paper finds that the marginal valuation of risk reduction is higher in high-education and high-income neighborhoods. The results also suggest that environmental risks are greater in neighborhoods with low-priced houses and in neighborhoods with low levels of collective action, suggesting that polluters consider these characteristics when making their siting decisions.     

On the geography of conventions

Summary. We study an evolutionary model in which heterogenous boundedly rational agents interact locally in order to play a coordination game. Agents differ in their mobility with mobile agents being able to relocate within a country. We find that mobile agents enjoy a higher payoff and always benefit from increased mobility, while immobile agents benefit from increased mobility at low levels of mobility only. This wedge in payoffs weakly increases as mobility increases. Some extensions are discussed. Received: January 10, 2001; revised version: December 4, 2002 RID="*" ID="*" We thank, without implicating in any way, George Mailath for helpful discussions. Some of the ideas in this paper were developed during the V Conference of the Society for the Advancement of Economic Theory in Ischia, Italy. The NSF provided financial support. Correspondence to: T. Temzelides     

FLASH GROWTH ESTIMATES USING CALENDAR INFORMATION

In 1991 Statistics Netherlands introduced their early flash estimates of the Quarterly National Accounts. In this article we examine a new, faster flash estimate, some three to four weeks earlier. The gain is made by using a simple regression technique and incomplete data. To compensate for the lack of data, information on the number of working days and shopping days was added to the regression. The inclusion of these calendar aspects significantly affect GDP growth: 0.30 percent point extra GDP growth for one extra working day, and 0.17 percent point for one extra shopping day.
The cost of an earlier estimate is a decrease of reliability. The probability of a forecast error of over 0.5 percent point will be about 26 percent, compared to 12 percent for the official flash estimate.     

Designing environmental policy: lessons from the regulation of mercury emissions

In its waning days, the Clinton administration decided that it was appropriate to regulate mercury emissions from power plants. The incoming Bush administration had to decide how best to regulate these emissions. The Bush administration offered two approaches for regulating mercury emissions from power plants. The first was to establish uniform emission rates across utilities, as mandated by the 1990 Amendments. The second was to establish a cap on mercury emissions while allowing emissions trading in order to reduce the cost of achieving the goal. This paper presents the first cost-benefit analysis of this issue that takes account of IQ benefits. We find that the benefits of the mercury regulation are likely to fall short of the cost. This assessment is based on a number of assumptions that are highly uncertain. The finding of negative net benefits is robust to many, though not all, reasonable variations in the model assumptions. We also find that the emissions trading proposal is roughly $15 billion less expensive than the command-and-control proposal. Mr. Gayer is associate professor of public policy at Georgetown University and a visiting scholar at the American Enterprise Institute. Mr. Hahn is co-founder and executive director of the American Enterprise Institute-Brookings Joint Center for Regulatory Studies and a scholar at AEI. We would like to thank Mary Jo Krolewski, Leonard Levin, Joel Schwartz, Anne Smith, Nik Wada, and Chris Whipple for helpful comments and Jordan Connors, Laura Goodman and Molly Wells for valuable research assistance. The views expressed in this paper represent those of the authors and do not necessarily represent the views of the institutions with which they are affiliated.     

Sustaining entrepreneurial business: A complexity perspective on processes that produce emergent practice

This article examines the management practices in an entrepreneurial small firm which sustain the business. Using a longitudinal qualitative case study, four general processes are identified (experimentation, reflexivity, organising and sensing), that together provide a mechanism to sustain the enterprise. The analysis draws on concepts from entrepreneurship and complexity science. We suggest that an entrepreneur’s awareness of the role of these parallel processes will facilitate their approaches to sustaining and developing enterprises. We also suggest that these processes operate in parallel at multiple levels, including the self, the business and inter-firm networks. This finding contributes to a general theory of entrepreneurship. A number of areas for further research are discussed arising from this result.     

中美对话 谁上谁下？

又一轮中美战略经济对话（SED）结束了。上一次由于双方表现不佳,我们认为对话是失败的,那么这次能打几分呢？这次要好于上次,不过奇怪的是,双方与会者在很多方面更换了角色。别忘了中美战略经济对话不仅仅关于经济,还涉及安全问题。当峰会临近之际,朝鲜半岛的局势恶化了。