Knowledge that Transforms

Gasoline taxes are widely perceived as the most efficient instrument for reducing gasoline consumption because they exploit all behavioral responses for reducing fuel use, including reduced driving and improved fuel economy. At present, however, higher fuel taxes are viewed as a political nonstarter. Pay-as-you-drive (PAYD) auto insurance, which involves replacing existing lump-sum premiums with premiums that vary in proportion to miles driven, should be more practical, since they do not raise driving costs for the average motorist. We show that when impacts on a broad range of motor vehicle externalities are considered, PAYD also induces significantly higher welfare gains than comparable gasoline tax increases, for fuel reductions below 9%. The reason is that under PAYD, all of the reduction in fuel use, rather than just a fraction, comes from reduced driving; this produces a substantial additional efficiency gain because mileage-related external costs (especially congestion and accidents) are relatively large in magnitude.(This abstract was borrowed from another version of this item.)

We analyze the colonial land revenue institutions set up by the British in India, and show that differences in historical property rights institutions lead to sustained differences in economic outcomes. Areas in which proprietary rights in land were historically given to landlords have significantly lower agricultural investments and productivity in the post-independence period than areas in which these rights were given to the cultivators. These areas also have significantly lower investments in health and education. These differences are not driven by omitted variables or endogeneity problems; they probably arise because differences in historical institutions lead to very different policy choices.

Many programs reward or penalize schools based on students' average performance. Mean reversion is a potentially serious hindrance to the evaluation of such interventions. Chile's 900 Schools Program (P-900) allocated resources based on cutoffs in schools' mean test scores. This paper shows that transitory noise in average scores and mean reversion lead conventional estimation approaches to overstate the impacts of such programs. It further shows how a regressiondiscontinuity design can be used to control for reversion biases. It concludes that P-900 had significant effects on test score gains, albeit much smaller than is widely believed

ing from complicated signaling behavior by informed authors. Lerner and Tirole show that adding upstream private information does not alter their basic analysis (their Proposition 4). 454 AEA PAPERS AND PROCEEDINGS MAY 2005

To study how a firm can capitalize on a long-term customer relationship, we characterize the optimal contract between a monopolist and a consumer whose preferences follow a Markov process. The optimal contract is nonstationary and has infinite memory, but is described by a simple state variable. Under general conditions, supply converges to the efficient level for any degree of persistence of the types and along any history, though convergence is history-dependent. In contrast, as with constant types, the optimal contract can be renegotiation-proof, even with highly persistent types. These properties provide insights into the optimal ownership structure of the production technology.

We develop a positive theory of the adoption of child labor laws. Workers who compete with children in the labor market support a child labor ban, unless their own working children provide a large fraction of family income. Fertility decisions lock agents into specific political preferences, and multiple steady states can arise. The introduction of child labor laws can be triggered by skill-biased technological change, which induces parents to choose smaller families. The theory can account for the observation that, in Britain, regulations were first introduced after a period of rising wage inequality, and coincided with rapid fertility decline.

This paper re-examines the returns to computer use using a new matched workplace-employee data from Canada. We control for potential selection using instrumental variables. Results suggest that it is not merely the employee having a computer on his desk, but rather having complementary computer skills, that causes wages to increase.(This abstract was borrowed from another version of this item.)

Does Competition for Capital Discipline Governments? Decentralization, Globalization, and Public Policy by Hongbin Cai and Daniel Treisman. Published in volume 95, issue 3, pages 817-830 of American Economic Review, June 2005

Will U.S. Agriculture Really Benefit from Global Warming? Accounting for Irrigation in the Hedonic Approach by Wolfram Schlenker, W. Michael Hanemann and Anthony C. Fisher. Published in volume 95, issue 1, pages 395-406 of American Economic Review, March 2005

People may be surprised to notice certain regularities that hold in existing knowledge they have had for some time. That is, they may learn without getting new factual information. We argue that this can be partly explained by computational complexity. We show that, given a knowledge base, finding a small set of variables that obtain a certain value of R 2 is computationally hard, in the sense that this term is used in computer science. We discuss some of the implications of this result and of fact-free learning in general.