Hoa Vu

Lecturer and Lead Economist
Northwestern University

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hoa.vu@northwestern.edu

Northwestern University
School of Education and Social Policy
Walter Annenberg Hall, 2120 Campus Drive
Evanston, Illinois 60208

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Peer Reviewed Publications

Womb to Wisdom: Early-Life Exposure to Midwifery Laws and Later-Life Disability
with Hamid Noghanibehambari, Hesamaldin Bagheri, Mostafa Toranji, and Nasrin Tavassoli
Social Science & Medicine, 2025, 372, 117973

Previous research documented that midwifery service quality improvements lead to improving maternal and infants’ health outcomes. However, little is known about its influence for later-life outcomes including disability. This paper explores the potential effects of early-life exposure to the establishment of midwifery laws across US states on later-life disability outcomes. Midwifery laws were enacted during the late 19th and early 20th century and required midwives to gain formal education and training to obtain a license in order to legally practice. We use decennial census data over the years 1970–2000 and implement a difference-in-difference method and show that being born in a reform state is associated with significant reductions in various measures of disability, including work disability, cognitive difficulty, ambulatory difficulty, self-care difficulty, and a proxy for severe mental health. We also find significant increases in education, socioeconomic scores, housing wealth, and income. We further discuss the policy implications of the results.

Born on the Wrong Side of the Tracks: Exploring the Causal Effects of Segregation on Infant Health
with Tiffany Green and Laura Swan
Journal of Health Economics, 2024, 95, 102876

Prior research has found that a high level of residential racial segregation, or the degree to which racial/ethnic groups are isolated from one another, is associated with worsened infant health outcomes, particularly among non-Hispanic (NH) Black infant populations. However, because exposure to segregation is non-random, it is unclear whether and to what extent segregation is causally linked to infant health. To overcome this empirical limitation, we leverage exogenous variation in the placement of railroad tracks in the 19th century to predict contemporary segregation, an approach first introduced by Ananat (2011). In alignment with prior literature, we find that residential segregation has statistically significant associations with negative birth outcomes among Black infant populations in the area. Using OLS methods underestimates the negative impacts of segregation on infant health. We fail to detect comparable effects on health outcomes among NH White infant populations. Further, we identify several key mechanisms by which residential segregation could influence health outcomes among Black infant populations, including lower access to prenatal care during the first trimester, higher levels of anti-Black prejudice, greater transportation barriers, and increased food insecurity. Given that poor birth outcomes have adverse effects on adults’ health and well-being, the findings suggest that in-utero exposure to residential segregation could have important implications for Black–White inequality over the life course.

I Wish I Were Born in Another Time: Unintended Consequences of Immigration Enforcement on Birth Outcomes
Health Economics, 2024, 33 (2), 345-362

This paper studies the effects of Secure Communities (SC), a wide-ranging immigration enforcement program, on infant health outcomes in the United States. Using administrative birth certificate data together with event study and triple-differences designs, I find that SC increases the incidence of very low birth weight by 21% for infants of foreign-born Hispanic mothers, who were most likely to be affected by immigration enforcement. There is suggestive evidence that the results are consistent with (i) changes in maternal stress induced by deportation fear and (ii) inadequate prenatal nutrition. A back-of-the-envelope calculation suggests that this unintended social cost of immigration enforcement ranges from $872 million to $1.59 billion annually.

Implicit and explicit racial prejudice among medical professionals: updated estimates from a population-based study
with Tiffany Green, Laura Swan, Dian Lou, Ellen Hickman, Marie Plaisime, and Nao Hagiwara
The Lancet Regional Health - Americas, 2023

Prior research provides evidence of implicit and explicit anti-Black prejudice among US physicians. However, we know little about racialized prejudice among physicians and non-physician healthcare workers. Using ordinary least squares models and data from Harvard’s Project Implicit (2007-2019), we assessed the associations between self-reported occupational status (physician, non-physician healthcare worker) and implicit and explicit prejudice toward Black, Arab-Muslim, Asian, and Native Americans, net of demographic characteristics. We found that physicians and non-physician healthcare workers exhibited more implicit and explicit anti-Black and anti-Arab-Muslim prejudice than the general population. After controlling for demographics, these differences became non-significant for physicians but remained for non-physician healthcare workers. Demographic controls largely explained anti-Asian prejudice among both groups and, physicians and non-physician healthcare workers exhibited comparatively lower and similar levels of anti-Native implicit prejudice, respectively. Finally, white non-physician healthcare workers exhibited the highest levels of anti-Black prejudice.

Exploring financial stress and resource deprivation as barriers to preferred contraceptive use in Wisconsin in 2021
with Laura Swan, Jenny Higins, Leeann Bui, Kristen Malecki, and Tiffany Green
Contraception, 2022, 115, 22-26

This study assessed a broad array of socioeconomic barriers in relation to preferred contraceptive use during a time of exacerbated personal and social financial strain (the COVID-19 pandemic). Using statewide data collected in early 2021 through the Survey of the Health of Wisconsin, we conducted bivariate analyses exploring the relationship between socioeconomic resources and preferred contraceptive use among Wisconsin women. Findings indicated that people lacking socioeconomic resources, including adequate food and housing, may be unable to access their preferred contraceptive method(s). Amidst competing demands on time and resources, the inability to obtain preferred contraceptive method(s) may represent system-wide barriers as well as people's lowered ability to prioritize and access care in light of socioeconomic struggles.


Working Papers

In-Utero Exposure to Abortion Legalization and Adult Disability and Mortality
with Hamid Noghanibehambari and Jason Fletcher
Revision requested, Demography

This paper examines the long-term health impacts of in utero exposure to legal abortion, a policy shift that occurred in the early 1970s in the United States. While prior research highlights the short-term benefits of legal abortion on maternal and infant health, such as reduced mortality and improved infant health outcomes, this study investigates whether these benefits extend into later life. Leveraging variation in the timing of abortion legalization across states and the complete set of death records, we find that exposure to legal abortion in utero leads to significant reductions in cumulative mortality and disability in adulthood. Our analysis of the mechanisms suggests that improved maternal and infant health, along with compositional changes in the characteristics of mothers giving birth, may explain these lasting health improvements.

Subminimum Wage Elimination and Economic Inclusion: Evidence from a National Analysis Michelle Yin and Regina Seo
Revision requested, Labour Economics

This study examines the labor market effects of eliminating subminimum wage employment (SWE) laws for people with disabilities (PWD) in the United States. Using data from the Current Population Survey and the staggered adoption of SWE reforms across states, we estimate causal effects using a difference-in-differences and event study framework. Our findings indicate that SWE elimination significantly reduces the share of PWD earning subminimum wages, with declines of six percentage points among prime-age adults and nine percentage points among young adults. These reductions occur without measurable adverse effects on overall employment rates or labor force participation, alleviating concerns about widespread job displacement. The reforms also lead to increased weekly work hours, higher annual earnings, and a shift away from low-wage service-sector employment. Further, we find no evidence of increased reliance on Supplemental Security Income, suggesting that the policy change does not induce greater dependency on public assistance. These findings provide the first national-level evidence on the labor market implications of SWE elimination, contributing to broader debates on wage policy and labor market regulation.

The Relationship Between Oil and Gas Production and Infant Health Outcomes: Evidence from National Data
with Hamid Noghanibehambari, Mahmoud Salari, and Nahid Tavassoli
Revision requested, Economics and Human Biology

This paper examines the effects of oil and gas production on infant health using birth records from 1990 to 2020. We focus on the rise of unconventional extraction methods—particularly hydraulic fracturing (“fracking”)—as a quasi-exogenous shock to local production. Exploiting the staggered discovery of fracking potential across shale counties, coupled with measures of production potential as identifying variation, we implement a difference-in-differences design to estimate the impact of drilling exposure on birth outcomes. We find that exposure to drilling activity significantly reduces birth weight, increases the incidence of low birth weight and preterm birth, and impairs fetal growth. Linking drilling to changes in local ambient pollution, we show that exposure significantly increases concentrations of ozone, PM2.5, PM10, and SO2—pollutants known to affect fetal development. These environmental changes likely contribute to the observed negative effects on infant health. Our findings offer insights into the broader costs and benefits of oil and gas extraction for local communities.

From Access to Wellness: Early Life Exposure to Abortion Legalization and the Next Generation’s Health
with Hamid Noghanibehambari and David Slusky
NBER Working Paper No. 33571 (Featured working paper) & IZA Discussion Papers No. 17760

We examine the multigenerational impacts of legalized abortion in the United States by analyzing how early-life exposure to this policy shift affects birth outcomes in the next generation. Using event study and two-way fixed effects models, we link maternal early-life exposure to legal abortion with improved birth outcomes in the subsequent generation, including higher birth weights and reduced rates of low birth weight. Our analysis of the mechanisms shows that these improvements in birth outcomes are not driven by changes in maternal racial or age composition within the treated generation. Instead, enhanced educational attainment and increased prenatal care utilization among the treated generation appear to play a critical role. Our results highlight the far-reaching implications of reproductive health policies, especially relevant in the post-Dobbs era, where access may once again become constrained for many.

Is Lynching Over? Long-Term Effects of In Utero Exposure to Racialized Violence in the U.S. Black Population
with Hamid Noghanibehambari, Jason Fletcher, and Tiffany Green
Under review

This study explores the long-term health effects of prenatal exposure to racialized violence by analyzing Social Security Administration death records linked with the 1940 census. We exploit variations in lynching incidences to understand their impact on old-age longevity. The results reveal a 3.7 month decrease in longevity for Black males who were exposed to a lynching of a Black victim during gestation. This exposure accounts for approximately 10% of the life expectancy gap between Black and White men in 1980, without negative effects observed among White individuals. Further analysis suggests reductions in socioeconomic measures are likely explanatory factors.

Lockdowns Echo: Exploring the Impact on Later-Life Longevity
with William Duncan and Hamid Noghanibehambari
Under review

Non-Pharmaceutical Interventions (NPIs) remain a subject of intense debate during major pandemics and endemics, with studies highlighting varied benefits and costs. Yet, little is known about the long-term effects of NPIs, particularly among those exposed during early life and childhood. This study examines the long-term effects of early-life and childhood exposure to NPIs implemented during the 1918-1919 influenza pandemic on later-life longevity. Utilizing Social Security Administration death records linked to the 1940 census, we investigate the differences in longevity of cohorts exposed to the pandemic during early childhood compared to those born post-pandemic, in cities with stricter NPIs to those with less stringent measures. The findings suggest a reduction in longevity of approximately 2.8 months for those exposed at ages 7-10. We attribute these effects to school closures and disruptions in children’s socioemotional and cognitive development and provide empirical evidence that their later-life reductions in education and socioeconomic status as potential pathways.

The Enduring Impact of Prenatal Exposure to Racial Riots on the Black Population

This paper provides causal evidence on the long-term health consequences of prenatal exposure to racial riots in the United States. We construct a novel database linking historical riot events to individual-level mortality records and Census data, and estimate difference-in-differences models that exploit quasi-random variation in birth timing relative to riot events. Our design compares changes in longevity across adjacent nine-month cohorts exposed to anti-Black versus non-Black riots. We find that prenatal exposure to anti-Black riots reduces Black Americans’ life expectancy by about 7.1 months. This effect is nearly twice the magnitude of the longevity reduction associated with prenatal exposure to lynchings documented in prior research, suggesting that the broader community disruption caused by riots—including housing loss, resource deprivation, and social dislocation—may have more severe long-run health consequences than individualized acts of racial terror. Our findings underscore the enduring biological imprint of structural racial violence and contribute to a growing literature documenting how early-life exposure to social shocks can shape long-term human capital and health outcomes.

Legacy of Equality: Black-White Teacher Pay Gap and Male Students’ Longevity
with Hamid Noghanibehambari, Jason Fletcher, and Tiffany Green

During school segregations of the early decades of the 20th century, Black teachers faced lower salary compared to their similarly qualified white counterparts owing to de jure segregated pay schedules. The National Association for the Advancement of Colored People (NAACP) embarked on a mission to equalize teacher salaries through court rulings and litigations. In several southern states, such litigations resulted in state policy reforms that restructured the pay schedule in an attempt to increase Black teachers’ salary. Prior literature documented that the reforms were successful in increasing salary, students’ enrollment, and grade progression. In this paper, we contribute to this literature by investigating the long-term impacts of these policies on students’ longevity. We find that a full exposure to the reform during school ages is associated with 2.5 months increases in longevity among Black males. Through a battery of tests, we rule out the concern that the results are confounded by within-state cross-cohort changes in longevity, within-state race-specific overall improvement in longevity, or socioeconomic and sociodemographic compositional change in the treated cohorts versus control cohorts. We discuss the policy implications of these results in light of the literature on later-life impacts of schooling inputs, emphasizing the imperative to address racial disparities in educational access and quality, which play a crucial role in shaping health outcomes for Black males.

Inclusive by Design: Unveiling the Effectiveness of Accommodations and Universal Design Elements through Process Data
with Burhan Ogut, Michelle Yin, Juanita Hicks, and Ruhan Circi
revision requested, Educational Measurement: Issues and Practice

This study examines the correlation between testing accommodations and universal design (UD) elements and standardized test performance within a digital testing framework. Utilizing a novel dataset—the National Assessment of Educational Progress (NAEP) process data—and advanced statistical methodologies such as inverse propensity weighting and doubly robust models, we provide compelling evidence on the efficacy of specific accommodations and UD features. Extended time usage significantly improves test performance for students with disabilities, emphasizing the crucial role they play in fostering equitable testing conditions. While scratchwork is associated with improved test performance for students with disabilities, the association between text-to-speech and equation editors, and student performance is mixed, suggesting potential distractions rather than support for some students.

Not Feeling Welcome: The Impact of 2016 Presidential Election on International Student Enrollments
with William Duncan
Under review

This paper examines the effects of the 2016 election on international student enrollments in the United States. Using variation in international student enrollments across U.S. higher education institutions, we find that the Trump election has a negative and significant impact on international enrollments. We provide suggestive evidence that Trump's 2016 win increases the weight on political factors when international students decide where to study. This is evidenced by the decline in international enrollments in Trump counties relative to Clinton counties. Some students, who would have chosen to study at a university in a Trump county may now no longer do so, favoring a university in a Clinton county. Other students who might once have chosen the U.S. for higher education now seem to be reconsidering and looking at other English speaking countries as alternatives.


Work in Progress

Beyond Women’s Empowerment: The Intergenerational Health Benefits of Contraceptive Access
with Hamid Noghanibehambari, Jason Fletcher, and David Slusky

Early Life Disease and Later Life Mortality: Evidence from the Polio Vaccination
with Hamid Noghanibehambari and Jason Fletcher

Medical Insurance and Financial Inclusion: Evidence from Low-Income Households
with Mingming Ji, Liangliang Jiang, and Michelle Yin

Effects of Medicaid Birth Cost Recovery Policy Changes on Child Support Outcomes
with Tiffany Green and Steve Cook