Research in public and applied economics has established ways for measuring the impact of government policies to answer policy-relevant questions within public, labor, and environmental economics. I tend to analyze the unexpected impacts of government policies that policymakers might not consider ex-ante, and I document the potential mechanisms underlying impacts on subjects.

Chapter 1 studies the question evaluating whether the single-sex schooling makes an impact on the future labor market outcomes, such as extensive margin of entering labor force and earning level. Entering single-sex schooling is not free from selection bias problem, as students choose the education institutes based on their preference. However, in South Korea, students are randomly assigned to high schools within the education district by lottery system, which makes it possible to find the treatment effect addressing the self-selection bias. We use the individual-level panel data spanned from their high school graduation until the late twenties and find the results which are heterogeneous by gender. Entering female single-sex high school decreases female earnings compared to the co-education high schools, whereas there is no solid evidence entering male single-sex high schools affects male labor market outcomes. We explore possible mechanisms for these asymmetric treatment effects, including the job sector choice and communication skills. Females from single-sex high schools tend to enter the healthcare industry as a worker such as nursing practice which pays lower income on average, and less enter the male dominant industry such as manufacturing. Furthermore, they show lower level of self-evaluation about the communication ability with coworkers compared to the females from the co-education high schools

Chapter 2 explores the impact of air pollution guideline change on pharmaceutical consumption. In South Korea, government changed the air pollution guideline related to the particulate matter 2.5 to improve the awareness of pollution seriousness. According to this change, the labeling of air pollution level became more strict. For example, the day labeled as “Normal” air pollution is now labeled as “Bad” after the policy change though it has the same level of air pollution. Exploiting this policy change and district-level spatial variation, we find that one additional day labeled as bad after the new guideline is associated with 0.9\% increase of medicine consumption related to the respiratory system per person. We also find that the impact is more negligible in one day of consecutive days of bad air pollution than a single day of bad air pollution. In addition to it, this impact varies by healthcare institutions; more accessible health care institutions (primary care and pharmacy) show a stronger impact than less accessible (tertiary) health centers.

Chapter 3 analyzes the research question of whether political alignment impacts the tax evasion rate in South Korea. According to the concept of reciprocity in tax morale, it is theoretically argued that a better attitude toward the government can lower the tax evasion motivation. Therefore, if the political alignment is correlated with attitude toward government, political alignment may affect the tax evasion rate. In this paper, we check this relationship between attitude toward government and political alignment from the Korean General Social Survey data set. Furthermore, by combining several Korean data sets, we find that people evade their tax payments less when politically aligned with the ruling party in South Korea.