The Social Science of Cities

The City

Cities account for an ever greater share of the world’s population.  In the U.S., urban areas now comprise more than 80 percent of the population and many cities are magnets for innovation and growth. We have come a long way since the urban changes documented in the classic text of 1925, The City.

Income inequality also continues to grow, sharpening the divergent pathways of cities and their neighborhoods.  What are the effects of this kind of urban inequality on the social cohesion of communities, cities, and the life chances of their inhabitants?  Are there long-term consequences for economic mobility, crime, and the development of human capital?  With projects in Boston, Los Angeles, and Chicago, I am studying these and other questions, with a major focus on everyday urban mobility.

Living in disadvantaged neighborhoods is widely assumed to undermine life chances because residents are isolated from neighborhoods with greater resources. Yet, residential isolation may be mitigated by individuals spending much of their everyday lives outside their home neighborhoods, a possibility that has been difficult to assess on a large scale. With colleagues, I have studied the consequences of urban mobility for the social structure of cities, including how a neighborhoods vitality depends not only on its own conditions, but also the conditions of the neighborhoods to which its residents are connected, through networks of everyday urban mobility. Based on this framework, we have highlighted three arguments. The first is that even though residents of disadvantaged neighborhoods may travel far and wide, their relative isolation by race and class persists. The second is that mobility-based socioeconomic disadvantage explains neighborhood rates of violence beyond residential-based disadvantage. Third, we argue that a city’s degree of social connectedness depends on how uneven and concentrated the networks of everyday mobility are among its neighborhoods, which in turn are hypothesized to predict rates of crime across cities beyond that expected by their residential-based segregation. We test these propositions using geocoded networks of movement throughout the 50 largest American cities. The results offer a new way of thinking about neighborhood effects, spatial inequality, and structural theories of crime.

Related Articles:

Wang, Ryan Q., Nolan Phillips, Mario Luis Small, and Robert J. Sampson. 2018. Urban Mobility and Neighborhood Isolation in America's 50 Largest Cities. Proceedings of the National Academy of Sciences 115: 7735–7740. See also Richard Florida on The Segregation of Our Everyday Lives in Atlantic CityLab.

Sampson, Robert J. and Brian L. Levy. 2020. Beyond Residential Mobility: Mobility-Based Connectedness and Rates of Violence in Large Cities. Race and Social Problems 1 2:77-86.

Phillips, Nolan, Brian Levy, Robert J. Sampson, Mario L. Small, and Ryan Qi Wang. 2019. The Social Integration of American Cities: Network Measures of Connectedness Based on Everyday Mobility across NeighborhoodsSociological Methods and Research.  See also Richard Florida, on How Socially Integrated Is Your City? Ask TwitterBloomberg City Lab.

Sampson, Robert J. 2019. Neighborhood Effects and Beyond: Explaining the Paradoxes of Inequality in the Changing American Metropolis. Urban Studies 56: 3 -32.


Boston Area Research Initiative

Professor Sampson is the founding director of the Boston Area Research Initiative (BARI), another project which seeks to spur original urban research on the cutting edge of social science and public policy. In conducting and interpreting this research, BARI forges mutually beneficial relationships among the region's scholars, policymakers, practitioners and civic leaders.  Today, BARI is directed by Daniel O'Brien at Northeastern University.

Over the years, BARI's organizers have focused on four primary strategies for achieving its goals: 

  • Providing opportunities for scholars and students to work with public officials on a variety of concrete projects, including support through internships and fellowships;
  • Creating two-way “data pipelines” and mapping tools that give researchers easier access to public data in ways not heretofore possible, and to give public officials easier access to academic analyses of the data;
  • Identifying core questions that concern both policymakers and scholars with the goal of facilitating original research that has both practical relevance and also addresses scholarly questions; and
  • Developing mechanisms that bring together officials and researchers in ways that ensure officials are aware of research findings and researchers are aware of policymakers’ knowledge and can learn from policymakers’ experiences in working on these topics. The  symposium that launched the initial effort of BARI in this area was held in the fall of 2011 at the Radcliffe Institute:

For more articles on the early years of BARI, see:

"Boston Neighborhoods Talk: Academics, City Government Officials Listen." Harvard Crimson. Wednesday, November 14, 2012

"Think Local: Why don’t Boston’s great professors study Boston? Top academics and city officials dig into a mystery."  Boston Globe, "Ideas" Section, October 9, 2011.

"When Town Meets Gown."  Harvard Gazette, October 27, 2011.

"Harvard and Boston" and "High-Tech Intersections."  Harvard Magazine, October 27, 2011.

"The City-University Connection."  NPR, November 14, 2011.

For BARI's current work, click here.