Three essays of this dissertation explore the impact of policies and shocks on education and health outcome of K-12 students and young adults.

Chapter 1 documents the gender achievement gap and gender difference in remote learning, exploiting differential exposure to remote learning induced by the COVID-19 pandemic. Using longitudinal administrative data of a school district in Georgia and employing Blinder-Oaxaca decomposition method, I find that exposure to disruptive peers in classroom and a lack of self-control generally have a detrimental effect on students' academic performance. Moreover, gender achievement gaps in both math and reading widen, favoring girls, over the course of the pandemic and the pandemic-induced shift to remote learning where gender-based impact differences in exposure to remote learning and proportion of disruptive peers in classroom explain considerable share of the gender gaps.

Chapter 2 estimates the impact of the universal gaming shutdown policy in South Korea. The analyses utilize 7-year panel data obtained from the Korean Children and Youth Panel Survey and employ a difference-in-differences method. Exploring heterogeneous effects of the policy based on students' pre-policy gaming pattern, I find that heavy gamers decreased their gaming hours by 26 percent of the pre-policy mean. The findings also suggest that the policy reduced the intensity of computer game usage and cellphone game usage among individuals who were heavy gamers.

Lastly, chapter 3 investigates the impact of the Affordable Care Act (ACA) Medicaid expansion on young adults falling in a "coverage gap". Utilizing the March Current Population Survey (CPS) and employing the difference-in-differences method, the results indicate that the ACA Medicaid expansion had a positive impact on the health insurance coverage rate of poor young adults who fell within the Medicaid coverage gap. In particular, young adults in expansion states experienced a significant increase in Medicaid coverage rate and a decrease in uninsured rate compared to those in non-expansion states. Moreover, the event study results suggest a gradual increase in Medicaid coverage rates and decrease in uninsured rate among young adults in expansion states in the years following the implementation of the expansion.