“Baby Bonus, Fertility, and Missing Women”, January 2021. Draft

This paper presents novel causal evidence on the effects of pro-natalist financial incentives on babies. I exploit rich spatial and temporal variation in the generosity of cash transfers provided to families with newborn babies and the universe of birth, death, and migrant registry records in South Korea. I find that the total fertility rate in 2015 would have been 3% lower without the cash transfers. These cash transfers were particularly effective among working mothers and encouraged them to have second and third children. This selection of working mothers into childbearing led to a decrease in gestational age, which in turn led to an overall reduction in birth weight, but no change in early mortality. The cash transfers had an unintended consequence of correcting the unnaturally male-skewed sex ratio closer to its natural level.

“Optimal Lockdown in a Commuting Network” (with Pablo Fajgelbaum, Amit Khandelwal, Cristiano Mantovani, and Edouard Schaal), November 2020. Draft / Slides / VoxEU / Codes and Replication

conditionally accepted at American Economic Review: Insights

We study optimal dynamic lockdowns against Covid-19 within a commuting network. Our framework integrates canonical spatial epidemiology and trade models, and is applied to cities with varying initial viral spread: Seoul, Daegu and NYC-Metro. Spatial lockdowns achieve substantially smaller income losses than uniform lockdowns, and are not easily approximated by simple centrality-based rules. In NYM and Daegu—with large initial shocks—the optimal lockdown restricts inflows to central districts before gradual relaxation, while in Seoul it imposes low temporal but large spatial variation. Actual commuting responses were too weak in central locations in Daegu and NYM, and too strong across Seoul.

“The Valuation of Local Government Spending: Gravity Approach and Aggregate Implications”, June 2020. Draft

How much do people value local government spending? What are the effects of fiscal transfers that finance this spending? I develop a spatial equilibrium framework where people’s simultaneous (internal) migration and commuting choices reveal preferences. I combine this framework with administrative data from South Korea and leverage the plausibly exogenous variation in local government spending across districts induced by national tax reforms in 2008 and 2012. The estimated mobility responses imply that workers value each additional dollar of per-capita local government spending by 75 cents of their after-tax income. The general-equilibrium counterfactuals imply that a fiscal arrangement with lower redistribution would result in aggregate gains. A key aspect of my analysis is that bilateral migration and commuting decisions are made jointly. I show that ignoring any one of these margins biases the estimates of preferences for public goods, distance elasticities of migration or commuting, and the aggregate effects of alternative fiscal arrangements.

Work in Progress

“Spatial Learning vs. Learning by Doing: Evidence from Airbnb Listings in New York City”

“International Trade, Pollution, and Welfare”, with Yasheng Zhang


Commuting and migration in Korea (2005; 2010; 2015): this dataset is used in "The Valuation of Local Government Spending: Gravity Approach and Aggregate Implications" and constructed based on the Population Census of Korea 2005, 2010, and 2015. ***permission required for data use***