Research

Publications Under Review

Reardon, S., Richardson, S. & Wilson, S. (2026). Gender Differences in Educational Effects of the COVID-19 Pandemic 

• Abstract: We use 15 years of test score data from roughly 7,000 U.S. school districts to examine how the pandemic differentially affected girls’ and boys’ learning outcomes and to investigate the community-level factors associated with these gendered effects. We find that gender gaps shifted toward boys in both math and reading more than at any point in the past 30 years. These shifts were not uniform. Girls lost more ground relative to boys in lower-socioeconomic-status communities and in places where the pandemic most severely disrupted daily life. Community socioeconomic resources buffered children against the academic consequences of disruption, but this protection was substantially stronger for girls than for boys. As a result, girls’ scores declined relative to boys’ far more in low-SES communities than in high-SES communities, even at comparable levels of disruption. We discuss the mechanisms by which acute societal disruptions may produce gendered educational effects.
• Media Coverage: Havard Gazette

Dee, T. and S. Wilson. (2025). The West Texas Measles Outbreak and Student Absences. (EdWorkingPaper: 25-1358). Retrieved from Annenberg Institute at Brown University: https://doi.org/10.26300/050d-c145

• Abstract: Declining child-vaccination rates are driving a measles resurgence in the US, yet little evidence documents how these outbreaks may disrupt schooling. Using daily absence data from a school district at the center of the West Texas outbreak, this preregistered analysis finds absences increased 41 percent relative to the within-year variation from two prior years, with larger effects among younger students. This increase is 10 times greater than expected from confirmed infections, suggesting substantial precautionary absences and possible infection undercounting. These findings provide early evidence on the impact of vaccine-preventable disease outbreaks on learning opportunities, with implications for broader child development.
• Media Coverage: Stanford GSE; Stanford Hoover Institute; Associated Press.

Yang, M., Wilson, S., Bromley, P., & Reardon, S. (2025). The Programme for International Student Assessment and the Dynamics of Education Reform Across 155 Countries, 1990-2018

• Abstract: PISA is often assumed to spur education reform, particularly in lower-performing countries. Germany’s “PISA shock” and subsequent reforms after surprisingly poor performance on the 2000 assessment is a classic example. Yet several other countries with similarly lackluster results do not pursue significant reforms. Using data from 155 countries between 1990 and 2018, we provide the first large-scale quantitative analysis of how PISA’s introduction relates to K–12 policy activity.
• Internal talks: Stanford’s Comparative Sociology Workshop (with Marcia Yang)

Publications In Progress

Wilson, S. (2026). The Effect of Universal Public Pre-K on Public School Enrollment: Evidence from Washington, D.C.

• Abstract: Little is known about whether universal pre-K (UPK) expansions affect public school system enrollment at scale. This study uses 25 years of population-level data from Washington, D.C. (1999–2023) to estimate the impact of UPK on public K–5 enrollment. D.C.’s UPK increased public kindergarten enrollment by 20% relative to a synthetic control of comparable school systems, with effects growing over time. The expansion attracted more families into the public system, increasing kindergarten participation among eligible children by 10 percentage points at implementation. These findings demonstrate that large-scale early childhood investments can alter participation in public education systems—relevant as districts nationwide face post-pandemic enrollment declines and rising competition from school choice alternatives.
• Conference presentations: Association of Public Policy and Management (2025); Association for Education Finance and Policy (scheduled, 2026).
• Internal talks: Stanford Advanced Topics in Quantitative Policy Analysis workshop; Stanford Public Economics II workshop.

Richardson, S., Wilson, S., & Reardon, S. (2026). Trends and Geographic Variation in US Early Childhood Opportunities and Skills at School Entry

• Abstract: We build a novel multi-state dataset of population-level kindergarten readiness assessment data and leverage these data to describe local variation and trends in early skills. We document substantial variation in readiness across school districts and strong associations between average readiness and community characteristics (particularly socioeconomic status). We also track changes over the past decade, highlighting pandemic-related declines in early skill and the uneven distribution of pandemic impacts across communities.

Stanford SCALE Initiative’s AI Hub For Education (2026). The State of AI in K12 Report.

• Abstract: In partnership with researchers from Stanford SCALE Initiative’s AI Hub For Education, we produce a high-quality report on the state of research on AI in K–12 education. The report highlights rigorous, causal evidence on AI’s impact on teachers, students, and school systems, surfacing both promises and pitfalls. The broader goal is offering actionable insights for policy, purchasing, and pilot programs related to AI in K–12 education for education system leaders, edtech companies, and researchers worldwide.

Research Initiatives in Progress

Examining the Impact of ChatGPT on Student Outcomes (in progress)

• In partnership with OpenAI, Estonia’s AI Lead Foundation, and University of Tartu researchers, we examine the impact of AI on student outcomes through a first-of-its-kind randomized controlled trial of country-wide ChatGPT deployment in Estonian high schools. Featured in SCALE Research In Action and the New York Times.