Knowledge that Transforms

We study ingroup bias —the preferential treatment of members of one’s group —in naturally occurring data, where economically significant allocation decisions are made under a strong non-discriminatory norm. Data come from Israeli small claims courts during 2000-04, where the assignment of a case to an Arab or Jewish judge is essentially random. We find robust evidence for judicial ingroup bias. Furthermore, this bias increases with terrorism intensity in the vicinity of the court in the year preceding the ruling. The results are consistent with theory and lab evidence according to which salience of group membership enhances social identification.

We show that the effects of taxes on labor supply are shaped by interactions between adjustment costs for workers and hours constraints set by firms. We develop a model in which firms post job offers characterized by an hours requirement and workers pay search costs to find jobs. We present evidence supporting three predictions of this model by analyzing bunching at kinks using Danish tax records. First, larger kinks generate larger taxable income elasticities. Second, kinks that apply to a larger group of workers generate larger elasticities. Third, the distribution of job offers is tailored to match workers' aggregate tax preferences in equilibrium. Our results suggest that macro elasticities may be substantially larger than the estimates obtained using standard microeconometric methods.

This paper uses a regression discontinuity design to estimate the effect of home computers on child and adolescent outcomes by exploiting a voucher program in Romania. Our main results indicate that home computers have both positive and negative effects on the development of human capital. Children who won a voucher to purchase a computer had significantly lower school grades but show improved computer skills. There is also some evidence that winning a voucher increased cognitive skills, as measured by Raven's Progressive Matrices. We do not find much evidence for an effect on non-cognitive outcomes. Parental rules regarding homework and computer use attenuate the effects of computer ownership, suggesting that parental monitoring and supervision may be important mediating factors.

This article develops a general equilibrium model of multiple-product, multiple-destination firms, which allows for heterogeneity in ability across firms and in product attributes within firms. Firms make endogenous entry and exit decisions and each surviving firm chooses optimally the range of products to supply to each market. We show that the resulting selection, across and within firms, provides a natural explanation for a number of features of trade across firms, products, and countries. Using both time-series changes in trade policy and cross-section variation in trade, we provide empirical evidence in support of the predictions of the model.

Do shocks to government spending raise or lower consumption and real wages? Standard VAR identification approaches show a rise in these variables, whereas the Ramey-Shapiro narrative identification approach finds a fall. I show that a key difference in the approaches is the timing. Both professional forecasts and the narrative approach shocks Granger-cause the VAR shocks, implying that the VAR shocks are missing the timing of the news. Simulations from a standard neoclassical model in which government spending is anticipated by several quarters demonstrate that VARs estimated with faulty timing can produce a rise in consumption even when it decreases in the model. Motivated by the importance of measuring anticipations, I construct two new variables that measure anticipations. The first is based on narrative evidence that is much richer than the Ramey-Shapiro military dates and covers 1939 to 2008. The second is from the Survey of Professional Forecasters, and covers the period 1969 to 2008. All news measures suggest that most components of consumption fall after a positive shock to government spending. The implied government spending multipliers range from 0.6 to 1.1.

In Almond et al. (2010), we describe how marginal returns to medical care can be estimated by comparing patients on either side of diagnostic thresholds. Our application examines at-risk newborns near the very low birth weight threshold at 1500 g. We estimate large discontinuities in medical care and mortality at this threshold, with effects concentrated at “low-quality” hospitals. Although our preferred estimates retain newborns near the threshold, when they are excluded the estimated marginal returns decline, although they remain large. In low-quality hospitals, our estimates are similar in magnitude regardless of whether these newborns are included or excluded.

This article analyzes the effect of competition on a supermarket firm's incentive to provide product quality. In the supermarket industry, product availability is an important measure of quality. Using U.S. Consumer Price Index microdata to track inventory shortfalls, I find that stores facing more intense competition have fewer shortfalls. Competition from Walmart—the most significant shock to industry market structure in half a century—decreased shortfalls among large chains by about a third. The risk that customers will switch stores appears to provide competitors with a strong incentive to invest in product quality.