Technological Change and Demand for Redistribution (submitted)
Latest draft: March 17, 2025
Job Market Paper
Abstract: I study the role of technological change in explaining rising income inequality and non-increasing progressive taxes from 1978 to 2018. Linking occupation-level data with individual responses on preferences for the redistribution of income, I document that occupations that increasingly required computer-related work experienced substantially reduced preferences for the redistribution of income, even when current earnings of individuals are accounted for. To rationalize this finding, I develop a tractable quantitative model embedding technological change and voting for redistribution, in which workers who are more exposed to computerization have more to gain from skill investment, and thus are more hurt by more distortive progressive taxes. Therefore, they are more opposed to progressive taxation. A decline in equipment prices leads to an increase in earnings inequality, while the tax progressivity is non-increasing. If workers’ skill acquisition were not allowed or a policymaking process is of equal weight across voters during the technological change, the model generates a higher level of tax-and-transfer progressivity and less inequality.
Dynamics of U.S. Tax Progressivity: A Quantile Approach (with Wentao Hu, Kun Ho Kim, Wei Biao Wu) (submitted)
Latest draft: June 2, 2025
Abstract: This paper investigates the dynamics of U.S. tax progressivity from 1978 to 2022 by conducting year-by-year quantile regression and simultaneous inference on progressivity estimates. We find that: (i) the least-squares fit of the widely used log-linear tax function capturing the residual income elasticity worsens during recessions, (ii) the U.S. progressivity is counter-cyclical at all income quantiles, with stronger counter-cyclicality at higher income quantiles; (iii) the constancy of the progressivity is rejected in the 1980s with a gradual decline and during recessions with jumps in the progressivity. During recessions, least-squares-implied tax rate is unusually higher than those from the quantile approach.
The Expansion of Social Media Platforms through Intangible Investment (with Xiaohan Zhang) (submitted)
Latest draft: December 24, 2025
Abstract: Social media platforms have expanded rapidly since the early 2000s as households shifted time toward online leisure, despite modest growth in measured labor and physical capital. To understand this gap, we build a multi-sector dynamic general equilibrium model in which platforms use online traffic and invest in intangibles, including leisure-enhancing technologies and data-intensive capital. Calibrating the model to time-use data, firm financial statements, and website traffic, we infer intangible values and productivity paths. From 2003 to 2023, platform growth is driven mainly by intangible accumulation and platform productivity, with intangible investment rising from 0.11% to 3.27% of GDP.
Political Participation, Intergenerational Transfer, and Capital Accumulation in General Equilibrium
Latest draft: September 15, 2021
Abstract: This paper studies the dynamic politico-economic theory in general equilibrium where repeated voting on an intergenerational tax and transfer system disproportionately aggregates policy preferences of households, and the relative political power depends on households' voting participation, i.e. endogenous turnout. In particular, I incorporate household's turnout decision in an otherwise standard overlapping generations model with capital accumulation. Political process is modeled by the probabilistic voting theory in which the political power emerges endogenously to household's primitives. I characterize the Markov perfect equilibrium and policy rules of the incumbent government and private sector saving. The Social Security tax exhibits a positive relationship with aggregate capital, in contrast to the independent relationship when voter turnout is exogenous. This suggests that agents are faced with a trade-off between political participation and economic welfare, and this trade-off depends on the extent to which the current generation extracts resources from the next unborn generation. The transitional dynamics shows that in response to population aging, capital accumulation and evolution of the endogenous tax rate are substantially different with exogenous and endogenous turnout.
Selected Works in Progress
Skill-promoting Policy and Changes in Technology and Labor Market Power (with Han Gao)
Online Leisure and Digital Platforms in an Open Economy (with Xiaohan Zhang)
Simultaneous Inference of Regression with Time-varying Random Coefficients (with Wentao Hu, Kun Ho Kim, Wei Biao Wu)
Carbon Burden in South Korea (with Sehoon Kim, Ju Hyun Pyun, Moonyoung Kim, Yeong Jae Kim)
Discussion Slides
Discussion Slides for “Perceived versus Calibrated Income Risks in Heterogeneous-agent Consumption Models,” by Tao Wang
Discussion Slides for “Unmasking Social Security: Navigating the Impact on Welfare Distribution,” by Eungsik Kim
Discussion Slides for “Does Protectionism Save Domestic Jobs?: New Evidence from Tariffs on Washing Machines,” by Jaerim Choi