Publications


School Bus Emissions, Student Health, and Academic Performance (with Dan Kreisman and Garth Heutel) Economics of Education Review. 2019.

Abstract (+)

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.

Working Papers


Throwing the Baby Out with the Ashwater? Coal Combustion Residuals, Water Quality, and Fetal Health.

Abstract (+)

Coal ash accounts for one third of industrial water pollution in the United States. No previous study has investigated how this form of water pollution may impact municipal water quality or human health. I assess the relationship between coal ash surface water discharges and three relevant outcomes: surface water quality measurements from the Water Quality Portal, municipal system water quality, and an individual birth data-set with mother identifiers and addresses linked to municipal water service zones. Identification relies on geographic variation in downstream status of monitoring sites and municipal water intake locations within small watershed regions. I also incorporate variation arising from plant closures and the relative quantity of coal ash released. I find that coal ash release sites are associated with higher conductivity and pH in both downstream surface waters and municipal water supplies sourced from these waters. Releases of coal ash increase disinfectant byproducts in municipal water systems, and water systems affected by coal ash tend to have more water quality violations for these compounds. I quantify the costs of coal ash water pollution with respect to fetal health and home sales. A newborn potentially exposed to coal ash water pollution is 1 to 1.2 percentage points more likely to be low birthweight compared to an unexposed sibling, although differences are not statistically significant. 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 $35,000.

Path to the Principalship and Value Added: A Cross-state Comparison of Elementary and Middle School Principals (with Bingjie Chen, Dan Goldhaber, Eric Hanushek, Kristian Holden, Cory Koedel, Helen Ladd, Jin Luo, Eric Parsons, Gregory Phelan, Steven Rivkin, Tim Sass, Mavzuna Turaeva) CALDER Working Paper No. 213-0119-1 2019.

Abstract (+)

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.

School Bus Diesel Retrofits, Air Quality, and Academic Performance: National Evidence Using Satellite Data.

Abstract (+)

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.

Farm-to-School Programs and Local Agricultural Revenues.

Abstract (+)

School meal provision represents one of the largest food markets in the country. 31 million students eat lunch or breakfast at 100,000 schools each year, with the federal government spending $13B annually on subsidized breakfast and lunch programs. 42,000 of these schools engage in farm-to-school nutrition sourcing policies. Little is known about how much school systems source their food locally or about the average relationship between farm-to-school policy adoption and local sourcing of school food. I link 17 years of school district nutrition expenditures across the state of Georgia to a unique commodity-by-county survey of agricultural revenues to assess how much school systems source food from within their county and neighboring counties. I then incorporate four years of survey-based information on district farm-to-school policies to test how farm-to-school programs differentially impact local sourcing patterns. Identification comes from spatiotemporal variation in school district adoption of the policy, where I present results of a simple difference-in-differences regression model, spatially-lagged regression models, and a plausibly causal triple difference specification exploiting variation in expenditures associated with an unrelated nutrition policy shift. Preliminary results suggest that $8B, or 4.7% of all agricultural revenues in the state from 2001-2017, may be attributed to nutrition spending by schools. Meanwhile, roughly $800M in local revenues may be attributed specifically to farm-to-school sourcing policies over the sample period.

An Analysis of the Effects of Implementing Personalized Learning Sass, Tim R. and Wes Austin. The National Center on Scaling up Effective Schools: Working Paper. September, 2019.

Abstract (+)

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.

Works in Progress


Municipal Water Quality and Fetal Health (with Mike Pesko).

CALDER Academic Mobility Project (led by a multi-state team).