How the reduction of Temporary Foreign Workers led to a rise in vacancy rates in South Korea
(Forthcoming in the Journal of Human Capital )
This study investigates the causal relationship between the reduction of low-skilled temporary foreign workers (TFWs) and job vacancies in South Korea's manufacturing sectors, utilizing the COVID-19 quarantine policy as a natural experiment. Employing a Difference-in-Differences methodology, the research reveals that sectors with high dependence on TFWs, particularly for permanent positions, experienced significantly elevated vacancy rates for a two-year period following the onset of the pandemic. The inability of native workers to fill these positions highlights the critical role of foreign labor in mitigating labor shortages. Notably, vacancy rates began to decline only after the government relaxed quarantine restrictions, facilitating the re-entry of TFWs into the country. These findings are corroborated by local projection methods.
The Causal Effects of Tariff-Rate Quota Policies on Agricultural Product Retail Prices
with Youngmi Kim (Under Review, Food Policy)
(한국어 버전 : Unpublished Institutional Working Paper Korean version, Not peer-reviewed)
This study examines the causal effect of Korea's Tariff-Rate Quota on consumer price reduction and stabilization, in contrast to previous foreign studies that focused on the domestic producer price support effects of Tariff-Rate Quotas. Using daily retail price data for 40 agricultural products from 2021 to 2025, this study analyze retail price changes in response to the intensity of tariff reductions using the Local Projection Difference-in-Differences method. The results indicate that while no significant price reduction was observed for leafy and root vegetables, fruits exhibited a causal retail price decline of approximately 0.9% for every one percentage point reduction in tariff rates. This implies that the tariff pass-through rate for fruits is approximately 90%. These findings suggest that when the policy objective is price stabilization, priority consideration should be given to applying Tariff-Rate Quotas to fruits.
Automation, Human Task Innovation, and Labor Share
(Under Review, Journal of Economic Behavior and Organization)
This study examines the impacts of robotic innovation (RI) and human innovation (HI) on labor share across nine EU countries. Using a general equilibrium model and novel shift-share instruments, we address endogeneity concerns by utilizing International Federation of Robotics data, US patents, and a Cognitive Tasks Index. Our findings show that until 2024, RI's negative impact has exceeded HI's positive effect on labor share. We estimate the elasticity of substitution between labor and non-robot capital at 0.52, and between labor and robots at 2.67. These results offer insights for policymakers addressing declining labor share, emphasizing the importance of fostering human innovation alongside technological advancement.
with Tai Lee (Work in Progress)
This study proposes an innovative methodology for quantifying Routine Task Intensity (RTI) and Cognitive Task Intensity (CTI) using Large Language Models to analyze O*NET task descriptions. Employing these LLM-derived measures, we reveal a consistent decline in routine occupations across Service and Sales sectors, with Sales receiving limited attention in existing literature. Regression analysis indicates a significant upward trend in cognitive impact on wages for females, particularly in Service, Sales, and to a lesser extent, Management occupations, while routine coefficients remain stable across five decades. These results underscore the growing significance of cognitive skills, especially for women in the workforce. Despite limitations in LLM output reliability and replicability, our methodology offers a complementary perspective to existing approaches, enabling a comprehensive understanding of labor market transformations.