Research
Research
The Effects of Educational Transitions on Adolescent Behavior and Mental Health
South Korean students transitioning from middle school to high school face longer school hours, increased academic pressure, and an older peer group. All of these have the potential to cause mental health problems. I estimate the effects of transitioning to high school from middle school on sleep patterns, risky behaviors, and mental health using a regression discontinuity design on date of birth. I find that students lose 40 minutes of sleep as they advance from middle school to high school, and their probability of trying alcohol or cigarettes goes up by 3.7 and 2.2 percentage points, respectively. Despite the reduction in sleep and the increase in risky behaviors, I find little evidence of statistically significant effects on various mental health measures, including stress, depression, and suicidal ideations or attempts. In fact, some measures of mental health improve with the transition to high school, which is surprising as there is substantial literature linking reduced sleep and substance abuse to worse mental health outcomes.
God is in the Rain: The Impact of Rainfall-Induced Early Social Distancing on COVID-19 Outbreaks (with Rolly Kapoor, Kinpritma Sangha, Bhavyaa Sharma, and Guanghong Xu)
Journal of Health Economics
January 2022, 81: 102575
The Impact of Delayed School Start Times on Sleep and Mental Health: Evidence from South Korea
This paper evaluates the effects of a 2014 school policy in South Korea that delayed start times to 9:00 a.m. for all public middle and high schools in one of the country’s largest regions. Using a difference-in-differences design and nationally representative data from the Korea Youth Risk Behavior Survey (KYRBS), I estimate the impact of the policy on students’ sleep duration and mental health outcomes. The reform led to an average increase of approximately 16 minutes in weekday sleep, primarily through later wake-up times. Despite this measurable gain, I find no significant changes in mental health indicators, including stress, depression, suicide ideation, and self-reported happiness. Two-stage least squares estimates, using the policy as an instrument for sleep, reinforce these null results, suggesting that modest increases in sleep may not be sufficient to yield meaningful psychological improvements. These findings underscore the limits of light-touch sleep interventions and emphasize the role of broader social and institutional contexts in shaping adolescent well-being.
The Impact of Mental Shock on Birth Outcomes: Evidence from the US Presidential Election in 2016
This paper investigates the impact of the 2016 U.S. presidential election on infant health, leveraging the unexpected outcome of the election as a quasi-natural experiment. Using restricted-use individual-level natality data from the CDC, we implement a difference-in-differences design to compare birth outcomes for infants exposed in utero during the election result period. We first examine differential responses by county-level political leaning, finding that birth weights declined modestly—but statistically significantly—in more Democratic-leaning counties. We then analyze maternal ethnicity as an alternative dimension of exposure, comparing outcomes between Hispanic and non-Hispanic mothers. In both approaches, we find small reductions in birth weight following the election, with limited evidence of effects on other outcomes such as prematurity or gestational age. These findings suggest that political shocks may generate modest physiological responses during pregnancy, though their interpretation requires caution given potential confounding factors.