Knowledge that Transforms

Science, are currently soliciting abstracts and papers covering applied or theoretical topics relevant to the analysis of treatment effects.Possible topics include, but are not limited to: treatment effect parameters/concepts social experiments propensity score and matching techniques control function approaches nonparametric bounds regression discontinuity approaches instrumental variables stochastic dominance, quantile regression, and other techniques used to evaluate distributional effects longitudinal methods dynamic treatment effects models measurement error, missing data, or other data issues.

External recruitment is often believed to be harmful in that it trades off the need for outside talents with the incentives of inside workers. This article shows that, even from an incentive viewpoint, external recruitment has its powerful function. Specifically, if promotion is based on relative performance, then negative activities (sabotages) are a valuable instrument for competition. This results in inefficiency of the firm. External recruitment, by reducing the marginal return of negative effort relative to that of productive effort, restores the incentives in productive activity. Even without sabotage concern, external recruitment can avoid shirking equilibrium or prevent workers’ collusion.

Relicensing requirements for professionals who move across borders are widespread. In this article, we measure the effects of occupational licensing by exploiting an immigrant physician retraining assignment rule. Instrumental variables and quantile treatment effects estimates indicate large returns to acquiring an occupational license and negative selection into licensing status. We also develop a model of optimal license acquisition that, together with the empirical results, suggests that stricter relicensing requirements may lead not only to practitioner rents but also to lower average quality of service in the market for physicians.

There is renewed interest in ways to enhance secondary education, especially among disadvantaged students. This study evaluates the short-term effects of a remedial-education program that provided additional instruction to under-performing high-school students in Israel. The program targeted 10th ntwelfth graders who needed additional help to pass the matriculation exams. Using a comparison group of schools that enrolled in the program later and implementing a differences-in-differences estimation strategy, we found that the program raised the school mean matriculation rate by 3.3 percentage points. This gain reflects mainly an effect on targeted participants and the absence of externalities on their untreated peers. The program was found to be less cost-effective than two alternative interventions based on incentives for teachers and students.

How does impatience affect job search? More impatient workers search less intensively and set a lower reservation wage. The effect on the exit rate from unemployment is unclear. In this paper we show that, if agents have exponential time preferences, the reservation wage effect dominates for sufficiently patient individuals, so increases in impatience lead to higher exit rates. The opposite is true for agents with hyperbolic time preferences: more impatient workers search less and exit unemployment later. Using two large longitudinal data sets, we find that various measures of impatience are negatively correlated with search effort and the exit rate from unemployment, and are orthogonal to reservation wages. Overall, impatience has a large effect on job search outcomes in the direction predicted by the hyperbolic discounting model.

This article develops and estimates a model of wage determination that isolates the effects of alcohol use on wages as mediated through human capital accumulation. Although generally insignificant, estimation results suggest that moderate alcohol use while in school or working has a positive effect on the returns to education or experience, and therefore on human capital accumulation, but heavier drinking reduces this gain slightly. Based on these results, alcohol use does not appear to adversely affect returns to education or work experience and therefore has no negative effect on the efficiency of education or experience in forming human capital.

The Journal of Economic Literature (JEL) regularly reviews books of interest to the economics profession. The Economic Report of the President (ERP) falls under that purview and beginning this year, the JEL will be reviewing the ERP. Toward that end, I have asked a handful of very prominent economists to review the 2005 ERP. Reviewers were chosen to reflect expertise on what I guessed would be key issues. Reviewers were given the following instructions: The ERP in principle should provide an accurate assessment of the consensus professional views of economists on any given issue, based on the research to date. Does the discussion in the ERP in fact accurately summarize what we as economists know? Reviewers were given free rein over what material they would review in the ERP but were urged to focus on their areas of particular expertise. In the reviews that follow, Joel Slemrod reviews the discussion of tax reform. Joe Farrell reviews the ERP's chapter titled “Innovation and the Information Economy.” Gordon Hanson reviews the chapters on international trade and on immigration. Robert Hall reviews the discussion of the adverse macroeconomic impact of rising oil prices while Jonathan Gruber reviews the ERP chapter titled “Expanding Individual Choice and Control.” Many thanks to the reviewers for the quick turnaround.

The theory of monotone comparative statics and supermodular games is presented as the appropriate tool to model complementarities. The approach, which has not yet been fully incorporated into the standard toolbox of researchers, makes the analysis intuitive and simple, helps in deriving new results and in casting new light on old ones. The paper takes stock of recent contributions and develops applications to industrial organization (oligopoly, R&D, and dynamics), finance (currency and banking crisis) and macroeconomics (adjustment and menu costs). Particular attention is devoted to Markov games and to games of incomplete information (including global games).

Neuroeconomics uses knowledge about brain mechanisms to inform economic analysis, and roots economics in biology. It opens up the “black box” of the brain, much as organizational economics adds detail to the theory of the firm. Neuroscientists use many tools— including brain imaging, behavior of patients with localized brain lesions, animal behavior, and recording single neuron activity. The key insight for economics is that the brain is composed of multiple systems which interact. Controlled systems (“executive function”) interrupt automatic ones. Emotions and cognition both guide decisions. Just as prices and allocations emerge from the interaction of two processes—supply and demand— individual decisions can be modeled as the result of two (or more) processes interacting. Indeed, “dual-process” models of this sort are better rooted in neuroscientific fact, and more empirically accurate, than single-process models (such as utility-maximization). We discuss how brain evidence complicates standard assumptions about basic preference, to include homeostasis and other kinds of state-dependence. We also discuss applications to intertemporal choice, risk and decision making, and game theory. Intertemporal choice appears to be domain-specific and heavily influenced by emotion. The simplified ß-d of quasi-hyperbolic discounting is supported by activation in distinct regions of limbic and cortical systems. In risky decision, imaging data tentatively support the idea that gains and losses are coded separately, and that ambiguity is distinct from risk, because it activates fear and discomfort regions. (Ironically, lesion patients who do not receive fear signals in prefrontal cortex are “rationally” neutral toward ambiguity.) Game theory studies show the effect of brain regions implicated in “theory of mind”, correlates of strategic skill, and effects of hormones and other biological variables. Finally, economics can contribute to neuroscience because simple rational-choice models are useful for understanding highly-evolved behavior like motor actions that earn rewards, and Bayesian integration of sensorimotor information. Who knows what I want to do? Who knows what anyone wants to do? How can you be sure about something like that? Isn't it all a question of brain chemistry, signals going back and forth, electrical energy in the cortex? How do you know whether something is really what you want to do or just some kind of nerve impulse in the brain. Some minor little activity takes place somewhere in this unimportant place in one of the brain hemispheres and suddenly I want to go to Montana or I don't want to go to Montana. (White Noise, Don DeLillo)