Research

Job Market Paper

What Do Measures of Decision-Making Ability Tell Us About Preventive Health Behavior? Evidence from Flu and COVID-19 Vaccination

Xuqian Ma

Vaccination is a choice under uncertainty that draws on two distinct abilities: forming beliefs about risks and acting consistently on one’s own preferences. Using the Understanding America Study, I measure the first with cognitive tests of quantitative ability and the second with choice consistency in an incentivized revealed-preference experiment. For influenza (2014–2026), neither predicts vaccination on average, but receipt falls over time especially post COVID among the least consistent adults, most sharply among Republicans, and the consistency gap grows most among adults with fewer chronic conditions, groups likely to perceive less risk. For COVID-19 (2021), quantitative ability predicts who got vaccinated earlier. The gap opens as each age group becomes eligible and reaches a similar size in each, so access mainly affects its timing. Higher-ability adults held more favorable beliefs about vaccine safety and effectiveness before most could get a dose, and these beliefs account for about 60 percent of the gap. This points to prosocial and norm-based messages for familiar vaccines, since they do not rely on perceived personal risk, and to early, clear safety information for new ones.

Publications

Impacts of Contemporaneous Air Pollution Exposure on Cognitive Performance in Kenya

Xuqian Ma, Michelle N. Layvant, Edward Miguel, Eric Ochieng, Ajay Pillarisetti, and Michael W. Walker

Journal of Health Economics, 109, 103166 (2026)

We estimate the short-term cognitive effects of fine particulate matter (PM₂.₅) exposure using highly localized readings from portable monitors deployed during cognitive assessments in Kenya. Higher exposure during testing is associated with lower performance in executive function, memory, and visuospatial tasks, with larger effects at higher exposure levels. The findings point to underappreciated human-capital costs of acute pollution exposure in low-resource settings.

Presentations: PAA 2025

Working Papers

War Exposure and Aging: Evidence from Vietnam War

Xuqian Ma, William H. Dow, and Yasuhiko Saito

Working paper

This paper studies the long-run effects of early-life war exposure on late-life human capital in Vietnam. We combine village-level bombing intensity from U.S. military records with geocoded survey data from the 2018 and 2021 waves of the Longitudinal Study of Aging and Health in Vietnam (LSAHV), linking individuals to local conflict exposure nearly five decades earlier. To address endogeneity, we exploit distance to the 17th parallel as an instrument for bombing intensity.

Presentations: PAA 2025 (Best Poster Award), ESE-RGHI-GHE Workshop on Health Economics in LMICs 2026, American Society of Health Economists Annual Conference 2026

Prenatal Air Pollution Exposure and Early-Childhood Cognition: The Role of Nutrition Intervention

Xuqian Ma, Yuhang Pan, Lingling Hou, and Renfu Luo

Revise & Resubmit at Journal of the Association of Environmental and Resource Economists

This paper examines the impact of prenatal exposure to air pollution on early childhood cognitive development and the potential mitigating role of nutritional interventions in China. Using variation in fetal exposure to PM2.5, we show that higher in-utero pollution levels reduce cognitive outcomes in early childhood. A randomized micronutrient supplementation program partially offsets these adverse effects, suggesting that improved nutrition can buffer some of the developmental damage caused by environmental shocks during gestation. These findings underscore the importance of complementary health and nutrition policies in alleviating the long-term consequences of environmental risk in developing countries.

Presentations: Psychology and Economics of Poverty Convening 2024, Pacific Conference for Development Economics 2024, 4th Asian Workshop on Econometrics and Health Economics