“We certainly hope that our work in New Haven will have greater application,” Roy said. “Although New Haven is small, it definitely has common urban problems. For the people living in these neighborhoods, violent crime has become the norm; I don’t think we have a misrepresentative sample.”

In the Yale study, New Haven residents were asked to fill out a survey of 55 questions pertaining to their experiences of violence and community engagement. Ultimately, the participants expressed interest in having more communal events and programs for youth, refurbishing abandoned homes and yards, and improving relationships with the police, said Dr. Carley Riley, another lead researcher on the Yale team. Such activities could improve the community’s ability to prevent and recover from gun violence, because they help to forge trust and cooperation among residents.

Notably, the majority of people surveyed knew none or few of their neighbors, and almost all had heard gun shots at some point. Two-thirds of them had a family member or friend hurt by an act of violence, with roughly 60 percent of the survey participants reporting that one of their loved ones had been killed.

Nonetheless, defining and measuring social cohesion can be challenging—even a U.N. report from 2010 described it as a “quasi-concept.” But it’s no leap in logic to suggest that the closer people in a community are to one another, the more resilient they will be in the face of violence.

Along similar lines, proponents of social cohesion often focus on areas affected by earthquakes and hurricanes for research: As Emma Green has pointed out, “it helps to like your neighbor during a natural disaster.” The basic logic here is that trust among residents makes way for more efficient recoveries. Thus, close social ties are no less vital in poor communities than in rich ones—and in fact, may be even more key to getting the members of poor communities back on their feet after incidents of gun violence.

Natural disasters aren’t acts of crime, but they have many of the same effects on communities. So it makes sense that social cohesion would help alleviate the problems resulting from both. A 2006 paper based on data from over 10,000 respondents across 20 local areas found that crime decreased as “sense of community” increased. That metric was defined as whether people worked together to improve their neighborhoods, felt safe walking at night, and trusted their neighbors.

Likewise, a 2013 study funded by the U.S. Department of Justice characterized community bonds as a resource of, by, and for the people. “Residents living in neighborhoods with close social ties tend to watch out for each other and their property,” it stated. “Intervening can include things like calling the police, asking questions of strangers, notifying parents if children are misbehaving, forming community groups to address problems, or attending city council meetings to request assistant from government.”