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This paper uses a unique data set to measure peer effects among college roommates. Freshman year roommates and dormmates are randomly assigned at Dartmouth College. I find that peers have an impact on grade point average and on decisions to join social groups such as fraternities. Residential peer effects are markedly absent in other major life decisions(More)
PRELIMINARY DRAFT Please do not cite or circulate without permission. Abstract We used a random-assignment experiment in Los Angeles Unified School District to evaluate various non-experimental methods for estimating teacher effects on student test scores. Estimated teacher effects from a pre-experimental period were used to predict student achievement(More)
We use six years of panel data on students and teachers to evaluate the effectiveness of recently hired teachers in the New York City public schools. On average, the initial certification status of a teacher has small impacts on student test performance. However, among those with the same experience and certification status, there are large and persistent(More)
Low birth weight (LBW) infants experience severe health and developmental difficulties that can impose large costs on society. However, estimates of the return to LBW-prevention from cross-sectional associations may be biased by omitted variables, such as genetic factors. To address this, we compare the hospital costs, health at birth, and infant mortality(More)
Most papers that employ Differences-inDifferences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law, we(More)
A large literature in medicine documents variation across areas in the use of surgical treatments that is unrelated to outcomes. Observers of this phenomena have invoked "flat of the curve medicine" to explain these facts, and have advocated for reductions in spending in high-use areas. In contrast, we develop a simple Roy model of patient treatment choice(More)
O ver the last decade, states have constructed elaborate incentive systems for schools using school-level test scores. By the spring of 2002, nearly every state and the District of Columbia had implemented some form of accountability for public schools using test scores. For instance, the state of Cali-fornia spent nearly $700 million on financial(More)
We examine the impact of increased abortion availability on the average living standards of children through a selection effect. Would the marginal child who was not born have grown up in different circumstances than the average child? We use variation in the timing of abortion legalization across states to answer this question. Cohorts born after legalized(More)