Research
Published Papers
- The Structure and Growth of Ethnic Neighborhoods (with Tianran Dai), Journal of Urban Economics, September 2023
final (page proof) version; MPRA working paper; project page; maps; replication archive
We introduce a new statistical definition of an immigrant ethnic neighborhood based on a choice model and using the location distribution of natives as a benchmark. We then examine the characteristics of ethnic neighborhoods in the United States using decadal census tract data from 1970 to 2010. We estimate that 43% of the foreign- born population lived in ethnic neighborhoods in 1970, increasing to 67% by 2010. Ethnic neighborhoods have lower average incomes and housing values, and a higher percentage of residents living in rental housing and commuting without a car, than other locations in the city where the same group lives. Neighborhoods vary greatly in size and the population distribution across neighborhoods within a group follows a power law. Most neighborhoods disappear within one or two decades but larger neighborhoods persist longer. Large neighborhoods have a well-defined spatial structure with negative population gradients from the center of the neighborhood and grow primarily through spatial expansion into adjacent locations.
- Delivery in the City: Differentiated Products Competition among New York Restaurants (with Jacob Cosman and Tianran Dai), Journal of Urban Economics, March 2023
–final (page proof) version; MPRA WP ; data and code repository for replication
We examine the response to entry in a large market with differentiated products using a novel longitudinal dataset of over 550,000 New York City restaurant menus from 68 consecutive weeks. We compare “treated ”restaurants facing a nearby entrant to “control ”restaurants with no new competition, matching restaurants using location characteristics and a pairwise distance measure based on menu text. Restaurants frequently adjust prices and product offerings but we find no evidence that they respond differentially to new competition. However, restaurants in locations with an entrant count in the top decile —areas with many new competitors —are 22% more likely to exit after a year than restaurants in the lowest entry decile.
- Reducing Frictions in College Admissions: Evidence from the Common Application (with Brian Knight), American Economic Journal: Economic Policy, February 2022
on AEJ website; NBER WP; Revised WP
College admissions in the U.S. is decentralized, creating frictions that limit student choice. We study the Common Application (CA) platform, under which students submit a single application to member schools, potentially reducing frictions and increasing student choice. The CA increases the number of applications received by schools, reflecting a reduction in frictions, and reduces the yield on accepted students, reflecting increased choice. The CA increases out-of-state enrollment, especially from other CA states, consistent with network effects. CA entry changes the composition of students, with evidence of more racial diversity, more high-income students, and imprecise evidence of increases in SAT scores.
- The Common Application and Student Choice (with Brian Knight), AEA Papers and Proceedings, May 2021
–on AEAPP website
In this paper, we investigate the role of the Common Application (CA) in increasing student choice in the college admissions process. The CA allows students to submit a single application to multiple colleges and has grown from 15 institutional members in 1975 to nearly 900 institutions today. By reducing frictions in the college admissions process, the CA facilitates applying to multiple colleges, potentially leading to more admissions offers for applicants, our definition of student choice. A greater degree of student choice thickens the market for higher education, contributing to a more integrated market and potentially enhancing competition among institutions for students. We investigate these issues using data from the Higher Education Research Institute (HERI) Freshman Survey over the period 1982–2014 and information regarding the timing of CA entry by colleges.
- The Out-of-State Tuition Distortion (with Brian Knight), American Economic Journal: Economic Policy, February 2019
–on AEJ website; final WP; NBER WP
Public universities typically charge much higher tuition to non-residents. We first investigate the welfare implications of this tuition gap in a simple model. While the social planner does not distinguish between residents and non-residents, state governments set higher tuition for non-residents. The welfare gains from reducing the tuition gap can be characterized by a sufficient statistic relating out-of-state enrollment to the tuition gap. We estimate this sufficient statistic via a border discontinuity design using data on the geographic distribution of students by institution.
- Cities and Product Variety: Evidence from Restaurants, Journal of Economic Geography, November 2015
-Winner of Urban Land Institute Prize for best 2015 paper in Journal of Economic Geography
on JoEG website; working paper version; ULI presentation; 中文摘要
This paper measures restaurant variety in US cities and argues that city structure directly increases product variety by spatially aggregating demand. I discuss a model of entry thresholds in which market size is a function of both population and geographic space and evaluate implications of this model with a new data set of 127,000 restaurants across 726 cities. I find that geographic concentration of a population leads to a greater number of cuisines and the likelihood of having a specific cuisine is increasing in population and population density, with the rarest cuisines found only in the biggest, densest cities. Further, there is a strong hierarchical pattern to the distribution of variety across cities in which the specific cuisines available can be predicted by the total count. These findings parallel empirical work on Central Place Theory and provide evidence that demand aggregation has a significant impact on consumer product variety. Click here for a longer discussion.
- Spatial Competition and Cross-border Shopping (with Brian Knight), American Economic Journal: Economic Policy, November 2012
on AEJ website; working paper version
This paper investigates competition between jurisdictions in the context of cross-border shopping for state lottery tickets. Our theoretical model, in which consumers consider both travel costs and lottery payoffs, predicts that per-resident sales should be more responsive to prices in small states with densely populated borders. Using weekly sales data from US lotteries and drawing identification from the rollover feature of jackpots, we estimate this responsiveness and find large effects that vary significantly across states. Using these estimates, we show that competitive pressures from neighboring states may lead to substantially lower optimal prices.
- Momentum and Social Learning in Presidential Primaries (with Brian Knight), Journal of Political Economy, December 2010
on JPE website; working paper version
New York Times coverage
This paper investigates social learning in sequential voting systems. In the econometric model, candidates experience momentum effects when their performance in early states exceeds expectations. The empirical application uses daily polling data from the 2004 presidential primary. We find that Kerry benefited from surprising wins in early states and took votes away from Dean. Owing to these momentum effects, early voters had up to five times the influence of late voters in the selection of candidates, and this helps to explain the distribution of advertising expenditures. Finally, we use the estimated model to conduct two counterfactual experiments.
