Research

1. When Cities Grow: Urban Planning and Segregation in the Prewar US Solo-authored job market paper, recipient of the Distinguished CESifo Affiliate Award (2023), the AREUEA Best Paper Award by a Junior Scholar (2022), and the IPUMS USA Research Award (2019).

How did zoning and transit infrastructure shape racial segregation in American cities? Combining a new panel dataset from historical U.S. federal censuses with newly digitized real-estate transaction records, this paper examines New York City from 1870 to 1940 and shows that between-neighborhood segregation rose dramatically with transit expansion, while the 1916 zoning code emerged largely as an endogenous response to the segregation that transit had already facilitated. Together, zoning and new subways produced a pattern in which inner-city neighborhoods zoned for factories and multi-family dwellings “flipped” to African American majorities; housing prices in tipped neighborhoods fell by 40 percent. White and African American migrants from the rural South both benefited from urban wage premia of roughly 40 percent — but this premium was substantially reduced for African American migrants who lived in segregated minority neighborhoods.

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2. Immigration, Innovation, and Urban Hubs: Theory and Evidence from the Age of Mass Migration With Costas Arkolakis and Michael Peters. Previously circulated as “European Immigrants and the United States’s Rise to the Technological Frontier.”

Mass migration to the United States between 1850 and 1920 brought millions of European workers to American cities — and reshaped where innovation happened. This paper develops a quantitative spatial model in which immigrants concentrate in urban hubs that, through knowledge spillovers and agglomeration economies, become engines of innovation for the broader economy. We assemble linked census and patent data spanning the period and use the model to quantify the contribution of immigration to America’s rise to the technological frontier. Our findings highlight the role of urban geography in translating immigration into long-run productivity growth.

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3. Debt, Drought, and Mobility: How Bankruptcy Institutions Shape Adjustment to Economic Shocks With Tao Chen, Marta Santamaria, Claudia Steinwender.

When economies are hit by climate or commodity shocks, how does the legal framework for personal debt shape who moves, who stays, and who recovers? This paper examines the adjustment of American agricultural communities to the droughts of the 1930s, exploiting variation in state bankruptcy regimes that altered debtor mobility and the cost of default. We show that more debtor-friendly bankruptcy institutions facilitated out-migration from drought-stricken regions, while restrictive regimes left households locked in place — with persistent effects on local economic recovery decades later. The paper draws on archival debt and migration records linked at the household level.

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4. Growing Through Vintages With Ana Cecília Fieler.

What drives long-run economic growth — the productivity of breakthrough ideas, or the rate at which they arrive? This paper studies how research, entrepreneurship, and labor reallocate across finely defined industries over more than 150 years of American economic history. We draw on the entire database of U.S. patents at the patent level (1836–present), a newly digitized Census of Manufactures (1860–1940), and newly harmonized County Business Patterns (1946–present). Our semi-endogenous growth model centers on the birth of “new nests” — entirely new product categories that set off boom-and-bust cycles of innovation and industry growth. We validate the model against text-based measures of patent influence, showing that the most influential patents cluster around the birth years of new nests. Quantitatively, the higher productivity of breakthrough ideas — not the rate at which new ideas arrive — accounts for 83 percent of U.S. economic growth since the 1870s.