The likelihood of experiencing gun violence may be less about the victims themselves and more about their acquaintances, a recent Yale study concludes.

The study observed increased probabilities of nonfatal gun violence among those in networks with other gun violence victims. Since most theories of criminology are based on networks, studying gun violence with network techniques was a logical methodology, said Andrew Papachristos, a Yale professor of sociology and study co-author. The findings, which were based on data from Chicago, have already informed the work of gun violence prevention programs in New Haven.

“I see networks at work in every city,” said New Haven Police Department Chief Dean Esserman. “The work [Papachristos] is doing in Chicago is as relevant in New Haven as it is in New York.”

In the study, the researchers created networks from the 2006-2012 records of the Chicago Police Department that outline cases of nonfatal gun injuries and arrests. The researchers used this data to construct a network linking individuals based on instances of being arrested for the same crime, also called co-offending. The network included over 100,000 individuals.

Analysis of this network found that approximately 70 percent of all nonfatal gunshot injuries in Chicago were associated with this co-offending network, which only comprised six percent of the Chicago population. Individuals within the co-offending network were over 12 times more likely to be the victims of nonfatal gunshot injuries than other people in the city.

One’s chance of falling victim also increases as an individual has more connections to other affected individuals, said Elizabeth Roberto GRD ’14, a Yale graduate student in sociology and co-author of the study.

Papachristos said he aims to use this research to improve empirically-driven violence prevention policies. More scientifically informed interventions can improve the effectiveness of deterrent messages by preemptively targeting at-risk individuals, he said.

“The severe concentration of violence in networks really changes how we think about gun crimes,” Papachristos said. “It helps us get a clearer picture of who the next victims might be.”

The team’s next steps include expanding the study from Chicago to other large cities to see if the patterns they observed are consistent. Data has been collected in Chicago and Boston, and the researchers’ sights are now set on New Haven, where a partnership between Papachristos and the New Haven Police Department has been under negotiation for over a year.

In addition to collecting data locally, there are efforts on the part of both the NHPD and local organizations to use this new understanding of gun crimes to prevent further violence. The NHPD has used Papachristos’ findings to combat gang violence by thinking about gun crimes as group behaviors. The department’s changed approach to how it thinks about and responds to violence has been accompanied by improved results, Esserman said.

New Haven antiviolence program Project Longevity has also adopted the network perspective in its own community outreach. Project Longevity offers support to individuals at risk of being involved in gun violence, whom they identify through network analysis. Other organizations, such as the National Network for Safe Communities (NNSC), have followed a similar approach to reach out to community members, said Amy Crawford, deputy director of the NNSC.

“The clear benefit of this approach is that it allows law enforcement to focus resources on the few individuals most likely to be involved in violence,” Crawford said.

In 2013, New Haven faced 18 homicides and 67 shootings.