Research

We use administrative panel data from seven states covering nearly 3 million students to document and explore variation in “academic mobility,” a term we use to describe the extent to which students’ ranks in the distribution of academic performance change during their public schooling careers. We find that student ranks are highly persistent during elementary and secondary education—that is, academic mobility is limited in U.S. schools on the whole. Still, there is non-negligible variation in the degree of upward mobility across some student subgroups as well as individual school districts. On average, districts that exhibit the greatest upward academic mobility serve more socioeconomically advantaged populations and have higher value-added to student achievement.

We examine the relationship between contemporaneous fine particulate matter exposure and COVID-19 morbidity and mortality using an instrumental variable approach. Harnessing daily changes in county-level wind direction, we show that arguably exogenous fluctuations in local air quality impact the incidence of confirmed COVID-19 cases and deaths. We find that a one &#956g/m&#179 increase in PM 2.5, or 15% of the average PM 2.5 concentration in a county, increases the number of same-day confirmed cases by 1.8% from the mean case incidence in a county. A one &#956g/m&#179 increase in PM 2.5 increases the same-day death rate by just over 4% from the mean. These effects tend to increase in magnitude over longer time horizons and are robust to a host of sensitivity tests. When analyzing potential mechanisms, we also demonstrate that an additional unit of PM 2.5 increases COVID-19-related hospitalizations by 0.8% and use of intensive care units by 0.5% on the same day. Using individual case records, we also show that higher PM 2.5 exposure at the time of case confirmation increases risk of later mechanical ventilation and mortality. These results suggest that air pollution plays an important role in mediating the severity of respiratory syndromes such as COVID-19.

Diesel emissions from school buses expose children to high levels of air pollution; retrofitting bus engines can substantially reduce this exposure. Using variation from 2,656 retrofits across Georgia, we estimate effects of emissions reductions on district-level health and academic achievement. We demonstrate positive effects on respiratory health, measured by a statewide test of aerobic capacity. Placebo tests on body mass index show no impact. We also find that retrofitting districts experience significant test score gains in English and smaller gains in math. Our results suggest that engine retrofits can have meaningful and cost-effective impacts on health and cognitive functioning.

Coal ash accounts for one third of industrial water pollution in the United States. I assess the relationship between coal ash surface water discharges and three relevant outcomes: surface water quality, municipal system water quality, and fetal health indicators from a birth certificate database in North Carolina. Identification relies on geographic variation in downstream status of monitoring sites and municipal water intake locations, plant closures or conversions, and the relative quantity of coal ash released over time. I find that coal ash releases are associated with higher conductivity and pH in both downstream surface waters and municipal water supplies sourced from these waters. Water systems affected by coal ash tend to have more Safe Drinking Water Act violations for disinfectant byproducts, inorganic chemicals, and health-based violations. I quantify the costs of coal ash water pollution with respect to fetal health and home sales. Exploiting variation arising from mothers' moves, I find that a newborn potentially exposed to coal ash water pollution is 1.7 percentage points more likely to have low birthweight compared to an unexposed sibling. I conclude by estimating how a legislative act mandating drinking well testing affected home sale prices in regions around coal ash plants. After the act, sale prices of homes within 1 mile of coal ash ponds declined by 12-14%, or over $37,000.

Prior work shows that air pollution affects cognitive performance. School bus diesel emissions meaningfully contribute to this exposure for school-age children. I exploit variation in the timing and location of 17,901 school bus diesel engine retrofits or replacements across the US from 2008 to 2016 to test how these bus fleet investments affect air quality and student test scores. I use satellite-based fine particulate matter (PM 2.5) measurements from the Atmospheric Composition Analysis Group to provide the first evidence that these engine retrofits significantly improve surface-level ambient air quality, suggesting potentially large spillover benefits. Retrofitting school buses is also associated with a 0.05-0.06 standard deviation increase in standardized test scores. Moreover, each additional microgram of fine particulate matter per cubic meter is associated with a precisely-estimated decrease in English and math test scores of 0.0056 standard deviations. Finally, I calculate the benefit of these test score and air quality improvements, finding that $170 million spent in grants by the EPA led to approximately $4.75 billion in external benefits. Whether considered from a mortality and clinic cost or test score perspective, the retrofits pass a benefit-cost test.

An increasing emphasis on principals as key to school improvement has contributed to efforts to elevate principal effectiveness that have taken various forms across the US. The primacy of the state as the focal point of educational reform elevates the value of understanding commonalities and differences among states in characteristics of principals, the distribution of principals among schools and ultimately the policies associated with more effective school leadership, particularly for disadvantaged children. This paper describes major state policies, the distribution of elementary school principals among schools along a several dimensions, and pathways to the principalship to illustrate similarities and differences among six states in the tenure and experience distributions and how these vary by student demographic characteristics and district size. Measurement of principal effectiveness and its relationship with principal characteristics and state policies would be ideal, but complications introduced by the dynamics of principal influences and confounding effects of other factors inhibit this effort. Nonetheless, school value added to achievement provides information on differences in principal effectiveness, and we report within-school variation value added across principal regimes and the associations between value added and principal characteristics. The analysis reveals many similarities and some differences among the states, some of which are related to differences in governance structures. Perhaps the most striking differences relate to the pathways to the principalship including the fraction of principals with experiences as assistant principals and teachers.

An increasing emphasis on principals as key to school improvement has contributed to efforts to elevate principal effectiveness that have taken various forms across the US. The primacy of the state as the focal point of educational reform elevates the value of understanding commonalities and differences among states in characteristics of principals, the distribution of principals among schools and ultimately the policies associated with more effective school leadership, particularly for disadvantaged children. This paper describes major state policies, the distribution of elementary school principals among schools along a several dimensions, and pathways to the principalship to illustrate similarities and differences among six states in the tenure and experience distributions and how these vary by student demographic characteristics and district size. Measurement of principal effectiveness and its relationship with principal characteristics and state policies would be ideal, but complications introduced by the dynamics of principal influences and confounding effects of other factors inhibit this effort. Nonetheless, school value added to achievement provides information on differences in principal effectiveness, and we report within-school variation value added across principal regimes and the associations between value added and principal characteristics. The analysis reveals many similarities and some differences among the states, some of which are related to differences in governance structures. Perhaps the most striking differences relate to the pathways to the principalship including the fraction of principals with experiences as assistant principals and teachers.