Americans travel 7 to 9 miles on average for shopping and recreational activities, which is far longer than the 15-minute (walking) city advocated by ecologically-oriented urban planners. This paper provides a comprehensive analysis of local trip behavior in US cities using GPS data on...

During the COVID-19 pandemic, states issued and then rescinded stay-at-home orders that restricted mobility. We develop a model of learning by deregulation, which predicts that lifting stay-at-home orders can signal that going out has become safer. Using restaurant activity data, we find that...

Does bounded rationality make paternalism more attractive? This Essay argues that errors will be larger when suppliers have stronger incentives or lower costs of persuasion and when consumers have weaker incentives to learn the truth. These comparative statics suggest that bounded rationality...

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,...

The pension landscape in the U.S. has changed dramatically over the past 25 years. Saving through personal retirement accounts has become the principal form of retirement saving. We document the transition from a defined benefit system to a personal account system and show the effect it has had...

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...

In the past few decades, some measures of population risk have improved, while others have deteriorated. Understanding the health of the population requires integrating these different trends. We compare the risk factor profile of the population in the early 1970s with that of the population in...