Knowledge that Transforms

This paper explains why payment card networks charge fees that are proportional to the transaction values instead of charging fixed per-transaction fees. We show that, when card networks and merchants both have market power, card networks earn higher profits by charging proportional fees. It is also shown that competition among merchants reduces card networks' gains from using proportional fees relative to fixed per-transaction fees. Merchants are found to earn lower profits under proportional fees, whereas consumer utility and social welfare are higher. Our welfare results are then evaluated with respect to the current regulatory policy debates.

This paper studies the impact of incentives on worker self-selection in a controlled laboratory experiment. Subjects face the choice between a fixed and a variable payment scheme. Depending on the treatment, the variable payment is a piece rate, a tournament, or a revenue-sharing scheme. We find that output is higher in the variable-payment schemes compared to the fixed-payment scheme. This difference is largely driven by productivity sorting. In addition, different incentive schemes systematically attract individuals with different attitudes, such as willingness to take risks and relative self-assessment as well as gender, which underlines the importance of multidimensional sorting.

While leading figures in the early history of economics conceived of it as inseparable from philosophy and other humanities, there has been movement, especially in recent decades, towards its becoming an essentially technical field with narrowly specialized areas of inquiry. Certainly, specialization has allowed for great progress in economic science. However, recent events surrounding the financial crisis support the arguments of some that economics needs to develop forums for interdisciplinary interaction and to aspire to broader vision.

Volunteering is a significant component of economic activity, especially for environmental organizations. Environmental organizations that rely on volunteers communicate with them using a variety of media, such as newsletters. This is a field experiment investigating whether tailoring the content of these communications to the stated motivations of a volunteer has a positive effect on the number of hours he/she volunteers. For the non-profit in our study, we find that such tailoring has an effect only for volunteers motivated primarily by career concerns. We also find this to be robust to the volunteers being aware that the tailoring is occurring.

This is a reply to “Stationary Concepts for Experimental 2 X 2 Games: Comment” by Brunner, Camerer, and Goeree which corrects some computational errors in Selten and Chmura (2008) and extends the comparison of five stationary concepts to data from previous experimental studies. We critically discuss their new findings and relate them to the data of Selten and Chmura (2008). We conclude that the parametric concepts of action-sampling equilibrium and payoff-sampling equilibrium perform better than quantal response equilibrium, and that the non-parametric concept of impulse-balance equilibrium performs at least as well as quantal response equilibrium.

In this paper we study the causal impact of police on crime, looking at what happened to crime and police before and after the terror attacks that hit central London in July 2005. The attacks resulted in a large redeployment of police officers to central London as compared to outer London. During this time, crime fell significantly in central relative to outer London. The instrumental variable approach we use uncovers an elasticity of crime with respect to police of approximately -0.3 to -0.4, so that a 10 percent increase in police activity reduces crime by around 3 to 4 percent. JEL: K42

We consider estimation of population averages when data are missing at random. If some cells contain few observations, there can be substantial gains from imposing parametric restrictions on the cell means, but there is also a danger of misspecification. We develop a simple empirical Bayes estimator, which combines parametric and unadjusted estimates of cell means in a data-driven way. We also consider ways to use knowledge of the form of the propensity score to increase robustness. We develop an empirical Bayes extension of a double robust estimator. In a small simulation study, the empirical Bayes estimators perform well. They are similar to fully nonparametric methods and robust to misspecification when cells are moderate to large in size, and when cells are small they maintain the benefits of parametric methods and can have lower sampling variance.

We propose a new measure of frictional wage dispersion: the meanmin wage ratio. For a large class of search models, we show that this measure is independent of the wage-offer distribution but depends on statistics of labor-market turnover and on preferences. Under plausible preference parameterizations, observed magnitudes for worker flows imply that in the basic search model, and in most of its extensions, frictional wage dispersion is very small. Notable exceptions are some of the most recent models of on-the-job search. Our new measure allows us to rationalize the diverse empirical findings in the large literature estimating structural search models.

Firms sometimes know more about a consumer's expected usage than the consumer herself. We explore the consequences of this reversal in the information asymmetry. We analyze the consequences of making consumers more informed about themselves. While making consumers more informed decreases their expenditure conditional on a given set of prices, equilibrium prices may increase, offsetting the direct benefit of information. We discuss theoretical and practical issues surrounding so-called RECAP regulation that would require firms to provide each consumer with information about her own usage of the firm's product.

We analyze the effect of search frictions in the market for commercial health insurance. Frictions increase insurance premiums (enough to transfer 13.2 percent of consumer surplus from fully insured employer groups to insurers—approximately $34.4 billion in 1997); and increase insurance turnover (by 64 percent for the average policy). This rent transfer harms consumers and—when combined with heightened turnover—reduces incentives to invest in future health. We also find that a publicly financed insurance option can improve the efficiency of private insurance markets by reducing search friction induced distortions in pricing and marketing efforts.