I am a Ph.D. Candidate in Economics at
Washington University in St. Louis.
I will be available for interviews at
the 2018 ASSA Meeting in Philadelphia, PA.
The Rise of Software and Skill Demand Reversal (Job Market Paper) PDF
Jobs have polarized in the U.S. since at least the 1980s: the employment share of low- and high-skill jobs grew at the expense of middle-skill jobs. But since the late 1990s, low-skill occupations increased even more and high-skill occupations less. We document that this change was accompanied by a rise in software innovation, and also provide empirical evidence that high-skill occupations rely more on software, and middle-skill occupations on equipment. We then propose a model with sorting and directed technical change that endogenously explains both employment share and software innovation trends. When occupations are complementary, productivity growth in the equipment-producing sector leads to a reduction in the employment share of middle-skill occupations which use equipment more intensively. Thus the demand for equipment declines, resulting in more software innovation than equipment innovation. This, in turn, leads to a skill demand reversal: if jobs are complementary, the rising employment share of high-skill occupations decelerates since they use software more intensively. Quantitative analysis shows that the model explains approximately two-thirds of the rise in software and skill demand reversal observed in the data.
Computerizing Industries and Routinizing Jobs: Explaining Trends in Aggregate Productivity (with Sang Yoon (Tim) Lee and Yongseok Shin), invited for the Carnegie Rochester NYU Conference for Public Policy, Journal of Monetary Economics, July 2018 PDF
Aggregate productivity growth in the U.S. has slowed down since the 2000s. We relate this to the rise of computers, and differential productivity growth across multiple jobs (routinization) and industries since the 1980s. In our model, complementarity across jobs and industries in production leads to aggregate productivity slowdowns, as the relative size of those jobs and industries that experienced high productivity growth shrinks, reducing their contributions toward aggregate productivity. During the 1980s and 1990s, this effect was countervailed by extraordinarily high productivity growth in the computer industry, of which output became an increasingly more important input in production across all industries (computerization). It was only as the productivity growth in the computer industry slowed down in the 2000s that the negative effect of differential productivity growth across jobs became apparent for aggregate productivity. Our quantitative results show that the decline in the labor share can also be explained by computerization, which substitutes labor across all industries.
Two Funding Sources and Exchange Rate Policy PDF
This paper analyzes the welfare implication of exchange rate policy in the presence of two substitutable funding sources: domestic and foreign. We show that a welfare rank of exchange rate smoothing depends on the share of foreign liability to total liability: Exchange rate smoothing becomes welfare superior to the free-floating when the share exceeds a certain threshold. Moreover, the threshold share itself varies by the degree of substitutability between two funding sources; the threshold share rises as the substitutability increases. The main implication of the results is that the policy recommendations from the model of a single funding source may be misleading when we analyze economies where domestic, as well as foreign borrowing, plays an important role.
Industrial and Occupational Employment Changes During the Great Recession (with Sang Yoon (Tim) Lee and Yongseok Shin), Federal Reserve Bank of St. Louis Review, Vol 99. No. 4, 2017 PDF
The U.S. labor market contracted sharply during the Great Recession. The ensuing recovery has been sluggish and by some measures still incomplete. In this paper, we break down aggregate employment during the Recession and the recovery into changes across industries and occupations. There is a clear asymmetric pattern: The contraction is driven by sectors and the recovery by occupations. In particular, the contraction between 2008 and 2010 primarily reflects a steep decline in construction employment, partially mitigated by expansions in the food services, education, and health industries. The recovery first came from a gradual increase in low-skill occupation employment across all sectors but after 2012 from a pronounced increase in high-skill occupation employment across all sectors. This pattern of recovery is a continuation of the underlying trend of polarization across occupations, which commenced in the 1980s.
PUBLICATIONS (in Korean)
The Role of Money and Banking in Monetary Policy (with Hyun-Euy Kim), Economic Analysis, vol 17:45-102, 2011 PDF
Unlike the prediction of financial accelerator model, a pro-cyclical relation between output and loan in Korea is weak. We extend banking attenuator model of Goodfriend and McCallum (2007) by assuming monitoring to be skilled labor to account for the Korean context where jobs in the financial sector are more secure and well-paying than the manufacturing sector. Results of the analysis show the attenuation effect has a quantitatively significant role in Korea.
The Money Demand Stability in Korea (with Kijung Park), Ewha Journal of Social Science, vol 20:133-168, 2008 PDF
Motivated by fast-growing monetary aggregates despite consecutive policy rate hike between the year 2005 and 2006 in Korea, we investigated whether money demand is stable. A large number of tests for structural breaks are conducted on various combinations of money demand determinants that are widely considered in the literature. We find stable money demand when house price is augmented. The results imply that fast-growing monetary aggregates were intricately linked with house prices, not a result of instability.
Uncovered Interest Parity: Duration, Expectation, and Non-linearity, Bank of Korea Monthly Bulletin, 2013-1 PDF
I examine empirical findings in the study of uncovered interest parity (UIP) using Korean data. I find evidences against the UIP condition for long-term as well as short-term interest differential and for rational expectations. However, introducing nonlinearity in UIP condition provides evidence for the UIP holding in an outer regime, consistent with theoretical prediction of limits to speculation hypothesis.
TA, Macroeconomics I (PhD Core), Washington University in St. Louis, Fall 2014, Evaluation
TA, Macroeconomics II (PhD Core), Washington University in St. Louis, Spring 2015, Evaluation