We study the effect of cash transfers on health disparities using data from the Department of Veteran Affairs’ Disability Compensation program, one of the nation’s largest cash transfer programs. Our instrumental variables strategy analyzes disability claims and medical records for over 800,000 veterans, leveraging the quasi-random assignment of these claims to two agents: caseworkers and physicians. Cash transfers reduce mortality on average, but there is considerable heterogeneity. Using only the caseworker instrument, we find that receiving $300 per month reduces 5-year mortality by 1.0 pp. Conversely, the physician instrument recovers a significantly smaller effect of 0.4 pp. We reconcile this discrepancy with a reverse selection-on-gains model, in which caseworkers and physicians differentially target cash transfers, but sicker veterans gain the least from transfers. Our findings help explain disparate findings in the literature and provide policy implications for targeting transfers to narrow disability-related health disparities.

Many medical innovations succeed in clinical trials but fail to make an impact outside controlled settings. This paper investigates why the introduction of pre-exposure prophylaxis (PrEP), whose trials demonstrate near-perfect efficacy in preventing HIV, coincided with a plateau in infections that halted decades of progress. Using epidemiological, pharmaceutical, and Census data, we estimate PrEP’s real-world effectiveness and investigate why the innovation failed to reduce population-level transmission. To address selection bias in uptake, we exploit two facts: PrEP is used almost exclusively by men who have sex with men, and regional concentrations of male same-sex partnerships vary widely. Counties with higher male same-sex partnership rates experienced greater PrEP uptake, which in turn lowered transmission rates. Our results imply that 76 additional users avert one new HIV diagnosis. We identify two primary factors contributing to PrEP's limited impact on aggregate HIV trends. First, while PrEP uptake is similar between Black and White men, eightfold higher incidence among Black men indicates substantial underutilization relative to need. Second, PrEP’s introduction was associated with increased risky sexual behavior among both users and non-users, further blunting the drug's real-world effectiveness.

Academic tracking enables educators to tailor instruction to students’ abilities. However, critics argue that tracking may lead schools to underinvest in lower- performing students, widening achievement gaps and amplifying existing inequalities. We test these hypotheses by examining the most widespread tracking program in the U.S.: Advanced Placement (AP). Leveraging the rapid expansion of AP in Texas following a statewide policy reform, along with detailed longitudinal microdata on students’ postsecondary and labor-market outcomes, we find that the introduction of AP courses increased students’ graduation rate by 3.9 pp on average, boosting college enrollment by 2.1 pp, college completion by 1.2 pp, and annual earnings by 3.3%. As predicted by our conceptual model, the largest absolute gains accrued to students with the highest pre-high school test scores. However, lower-performing students, who rarely participate in AP courses, also experienced modest absolute improvements — but large relative gains — in educational outcomes, suggesting lower-performing students received more tailored instruction and positive spillover effects within schools. Contrary to concerns that AP disadvantages non-college-bound students, our estimates reject that tracking harms the secondary, postsecondary, or labor-market outcomes of any academic, racial, or socioeconomic group.

We study the enrollment and equity effects of a unique college admissions policy: a preference in admissions for students applying from local high schools. In the mid-2000s, 18 California State University (CSU) campuses were mandated to prioritize applicants from local high schools; however, only nine campuses offered a meaningful local preference in practice, which we call “adherent” campuses. We estimate the effects of exposure to a local admissions preference using a difference-in-differences design that interacts an indicator for being local to an adherent as opposed to a non-adherent campus with an indicator for being pre or post policy implementation. Our results show that the policy induced students to enroll at their local campuses, without evidence of crowd-out from other public four-year colleges in California. Effects are only found for students from high schools with a high share of underrepresented minority (URM) students. As a result, the formally race-blind local preference policy nearly eliminates the pre-existing gap in enrollment at California public four-year colleges between students from high and low URM share high schools.

Monetary incentives for vaccination may undermine intrinsic motivation, but evidence on this effect remains scarce. We conducted an experiment among 513 vaccine-hesitant adults to test whether priming individuals with a monetary incentive reduces their willingness to vaccinate against COVID-19. Our findings show that one in seven were willing to vaccinate without an incentive but declined the vaccine when asked to consider a payment. Additionally, priming participants lowered their perceptions of vaccine safety by 9 pp and prosocial attitudes toward vaccination by 10 pp. These negative effects were concentrated among men, racial and ethnic minorities, and participants with lower preexisting trust in the vaccine. Our results highlight an unintended consequence of vaccine incentives.