Robert Sampson

He was speaking about broken windows and other forms of urban blight that suggest a lack of trust, cohesion, and collective social control (or, lack of order) within a neighborhood–big problems when trying to revitalize a community. These indicators affect what Sampson calls "collective efficacy" and could help explain crime, disorder, and the persistent presence of poor neighborhoods in an otherwise robust American economy.

What makes a neighborhood disadvantaged, Sampson asked. What makes one section of a city safe and another violent? Why does one community thrive and another stagger to survive?

Answers may be found in one of the country’s biggest cities, Chicago. Before coming to Harvard University as a professor, Sampson served as scientific director for the Project on Human Development in Chicago Neighborhoods (PHDCN), a longitudinal study. Felton Earls, professor of human behavior and development in the Department of Society, Human Development, and Health, was principal investigator on the project.

The project team divided Chicago into 343 neighborhood clusters composed of about 8,000 residents. Thousands of residents in those clusters were interviewed in 1995. Interviews were repeated in 2002.

In the intervening years, SUVs with video cameras rolled through neighborhoods. Those tapes were scanned for signs of community health (landscaping, rehabilitated housing, bustling shopping areas) and decline (abandoned or damaged buildings, drug sales, prostitution, vagrancy, or school truancy).

Archival records were also included in the study.

Researchers analyzed the videos, interviews, and archives, assigning ratings to each cluster based on the strength of social ties, such as family relationships or religious affiliation, and on the presence of cohesion and social control within a community–or its collective efficacy. A community that watches out for its young and elderly, joins together to push for a new traffic light, or organizes a block party would show good collective efficacy.

Ratings were correlated with rates of homicide, disease, infant mortality, low birthweight, and accidental injury.

The researchers were surprised to find that communities with residents who had strong social ties but did not trust their neighbors or share expectations for taking collective action had high rates of homicide. In other words, strong social ties did not necessarily protect against homicide. Instead, collective efficacy emerged as a significant factor.

Careful monitoring along with population-based interventions may prevent the decline of a particular neighborhood, said Sampson. City planners can help by working with public health professionals and sociologists to design prevention programs, reduce segregation, and distribute resources within cities.

"With respect to neighborhood inequality, there is little change absent intervention," Sampson said.

The Sol Levine Memorial Lecture was sponsored by the Harvard Center for Society and Health, Boston University School of Public Health, and the Health Institute at the New England Medical Center.

--PHC