Should the national government undertake policies aimed at strengthening the economies of particular localities or regions? Agglomeration economies and human capital spillovers suggest that such policies could enhance welfare. However, the mere existence of agglomeration externalities does not...

Do urban children live more segregated lives than urban adults? Using cellphone location data and following the 'experienced isolation' methodology of Athey et al. (2021), we compare the isolation of students over the age of 16--who we identify based on their time spent at a high school--and...

How effective are restrictions on mobility in limiting COVID-19 spread? Using zip code data across five U.S. cities, we estimate that total cases per capita decrease by 20% for every ten percentage point fall in mobility. Addressing endogeneity concerns, we instrument for travel by residential...

Empirical research on cities starts with a spatial equilibrium condition: workers and firms are assumed to be indifferent across space. This condition implies that research on cities is different from research on countries, and that work on places within countries needs to consider population,...

Recent literature on the relationship between ethnic or racial segregation and outcomes has failed to produce a consensus view of the role of ghettos; some studies suggest that residence in an enclave is beneficial, some reach the opposite conclusion, and still others imply that any relationship...