Research

Working Papers



This paper studies the extent to which delaying or skipping medical care affects infant and maternal health, using medical procedure delay executive orders issued by more than thirty US states at the beginning of the COVID-19 pandemic and a nationwide large claims dataset. Fuzzy RD estimates suggest that infants born after the orders are issued are more likely to experience postponed emergency room or urgent care visits, miss immunizations, have health issues related to the perinatal period, and show delayed physiological development, particularly among those less than four months old. Moreover, difference-in-difference results show delayed medical care threatens infant health through maternal health. Newborns delivered by women with pregnancy exposure to procedure delay orders are more likely to be low birth weight, and women are more likely to develop pregnancy-related health problems after procedure delay orders.




This paper examines the long-term impacts of the Area Health Education Centers (AHEC) program that promotes medical education and training to local communities. Using an event study strategy, I find the AHEC program increases local healthcare workforce. I show cohorts with childhood exposure to the AHEC program are less likely to be overweight and develop health limitations, report better subjective health, are less depressed, and consume fewer alcohol drinks and cigarettes than those without any childhood exposure to a local AHEC. Furthermore, these cohorts are more likely to remain enrolled in school after 16 and pursue a higher education degree.




This paper investigates the impacts of early life exposure to persecution on human capital formation and marriage market outcomes and analyzes how such impacts depend on the timing of the exposure over early life. By utilizing the "class struggle" period of China in the form of persecuting landlords, capitalists, intellectuals, etc., I show that persecution survivors with longer early childhood exposure to persecution complete less formal schooling, have worse cognitive skills, and earn lower incomes in the long run. Furthermore, they are more likely to marry people from classes once favored by the regime but with poorer human capital outcomes.




Institutional leaders have long championed interdisciplinary research; however, researchers have paid relatively little attention to the people responding to such calls and their subsequent career outcomes. With the benefit of two large datasets spanning from 1986 through 2016, we show that interdisciplinary dissertations have become consistently more common in recent years as institutional leaders have highlighted the value of boundary-spanning research for solving important and emergent problems. With the benefit of survey data from a near-complete population of all dissertators in the US starting in 2001 through 2016, we observe a consistent upward trend in interdisciplinary dissertations. Unfortunately, we show that these interdisciplinary dissertators have experienced a comparably persistent penalty when considering salaries for their first year after earning the PhD. We also show that among interdisciplinary dissertators, individuals in lower-paying fields tend to earn more when choosing distantly related topic-combinations whereas researchers in higher-paying fields tend to be most rewarded for staying within relatively narrow disciplinary silos.




The novelty of this paper is to comparatively study the intergenerational economic mobility in rural and urban China through an exploration of multiple intergenerational transmission mechanisms. Comparing rural and urban households in China, this paper finds lower intergenerational economic mobility in urban areas over the past quarter century (1989 to 2015). Furthermore, using the predicted community level time-invariant measures as instruments, the 2SLS estimates show that parental human capital has a bigger impact on child income in rural than urban China, while parental nonhuman capital goods, such as household wealth and social spending, are relatively stronger intergenerational economic transmission mechanisms within the urban households than the rural ones. This paper casts light on the heterogeneous intergenerational economic transmission patterns in China's dual society under the Rural-Urban Household Registration System. Moreover, the existing rural-urban difference of intergenerational economic transmission does not diminish with internal migration.



  • Medical Practice Shutdowns and Healthcare Utilization: Evidence from the COVID-19 Pandemic (with Rebecca McKibbin)


This paper studies the impacts of the COVID-19 pandemic on office-based physician practices and the further effects on patient healthcare utilization. We use a nationwide claims dataset to investigate all types of claims from January 2018 to January 2021. An event study design shows that physician practices are negatively affected by the COVID-19 pandemic, with fewer patient visits, lower revenues, and higher probabilities of permanent shutdowns among these practices after Stay-at-home orders are issued. Moreover, the impact of physician practice closures was disparate, leading patients who previously used physician practice services more frequently to visit hospitals and ED and pay higher costs per service if they switch to other surviving physician practices. Heterogeneity analysis shows that practices run mainly by female doctors and those located in ZIP code areas with higher minority population shares and lower per capita incomes are disproportionately affected during the COVID-19 pandemic.




The United States rose to become a global leader in scientific research in the early 20th Century. Using comprehensive data matching the universe of ProQuest PhD recipients to the full count decennial US Censuses (1850-1940), this paper investigates how access to PhD training facilitated research manpower in the US during this critical period. Evidence from our event study design suggests that opening one more PhD program during the peak ages of graduate study induces about 2 more PhD recipients per 1 million people born in that state. Furthermore, the expansion of PhD programs improved access for minority, immigrant, and lower socioeconomic status families. We also find that the location and field of the PhD program openings help to determine the institution and research area of doctoral recipients.




Marketing and strategy researchers have often studied how firms navigate multiple identities but less attention has been paid to understanding how individuals do so. As a model domain to examine this question, we focus on interdisciplinary dissertators in the United States since there are clear uptrends in dissertators engaging multiple identities and unclear trends in their outcomes. We introduce a novel two-step econometric approach to characterize salaries of interdisciplinary dissertators as functions of the identities (academic fields) they acquire as graduate students. In our approach, the key is to treat people with multiple identities (academic fields) as linear or non-linear combinations of their separate identities. To do this, we estimate a first-stage regression, where we regress earnings for monodisciplinarians on field dummies and respondent characteristics. After capturing the estimated discipline effects, we then regress earnings for interdisciplinarians on combinations of these estimated discipline effects. Our estimates robustly reject the hypothesis that interdisciplinarians receive a wage premium. We also find evidence that the market prefers to compensate researchers by their primary discipline, an outcome that challenges emphases on interdisciplinarity. While our findings among interdisciplinarians point to the primary identity holding predominant importance for doctoral graduates in the United States, our two-step method provides a framework for studying the varied impacts of multiple identities across contexts.



  • Robots, Demand for Skill and Inequality: Evidence from the China Employer-Employee Survey (with Albert Park and Xiaobo Qu)


This paper examines the equilibrium effects of the most recent automation technology transition towards industrial robots in the manufacturing industry using the newly collected China Employer-Employee Survey (CEES) data. We correct the endogeneity issue by using the constructed provincial capture of nationwide robotics technology as the instrumental variable for the individual firm's use of industrial robots. The 2SLS estimates show that the use of industrial robots in manufacturing firms awards wage premiums to all types of jobs and workers, meanwhile, also reshapes the employment structure and augments wage inequality within the firm. Moreover, the heterogeneity analysis across education groups, occupation levels, and task contents suggests that the shift in the demand for skill is the mechanism, through which the industrial robots affect the labor market.



Work In Progress


  • Short-term and Long-term Impacts of Childhood Exposure to Racial Injustice



  • Out of the University, Into the Workforce: Early 20th Century Scientific Training and Industrial Research (with Peter Nencka)


  • Short-term and Long-term Impacts of Opening Medical Schools (with Rebecca McKibbin and Ioanni Nicholopoulos)