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Using maps and networks to reduce gun violence

Sociology professor Andrew Papachristos deploys big data to help cities save lives

“The average age of a gunshot victim in Chicago is about 27 years old. Everybody thinks it’s younger, and that means that gun violence prevention efforts are not nearly as targeted and effective as they could be.” 

gun violence
Andrew Papachristos

Sociology professor Andrew Papachristos has been interested in criminal justice ever since childhood, when his Greek immigrant parents were the victims of gang violence on Chicago’s North Side. Now, his research applies public health concepts and network science to map gun violence in U.S. cities, in an effort to save lives and craft more effective long-term prevention policies. 

“We should address youth violence, but the older population — the population most at risk — is often overlooked in prevention programs,” Papachristos says. “If an organization is working on gun violence, and they only focus on 12 year oldsthey need to think about directing some resources to older groups, too.” 

Smarter solutions 

Papachristos has shown that violence cascades through communities, much like an infectious disease spreads through a school or city. He has also found that seemingly isolated events — shootings that are not retaliatory, for example — predict subsequent violence within network. With these findings in mind, Papachristos believes gun violence — much like opioid abuse or another public health problem — demands multilayered solutions.  

“We need to save lives today, and at the same time we need to implement long-term strategies,” he says. “If I come in with a heart attack, and you save my life, I should also have access to primary care that will help me with other parts of my physical and mental health. At the same time, I should have access to nutritious food and other community resources.” 

Intervention and prevention 

Networking gun violence, Papachristos says, strongly suggests that very focused interventions can produce immediate reductions in gang violence. Importantly, network data allow for interventions customized to individual circumstances 

“I can look at the data and say, ‘Andy got shot. What do we know about Andy?’ Papachristos says. “If Andy is in the system, we know where he lives, if he has mental health issues, if he’s in school, if he has kids. And then we can send support services to make sure Andy’s kids are ok, or make sure Andy has access to counseling. We can send resources we already have that work for this specific case.” 

Gun Violence Network of ChicagoA network showing a Chicago Public School gunshot victim and his network of co-arrestees

Papachristos acknowledges that this sort of intervention is an ideal: It faces many challenges and requires various groups — police, community groups, outreach workers — to work together and share data.  

“Everybody wants their group to be the one doing the work and getting the resources,” Papachristos says. “A more effective system would require everyone to be both flexible and nimble. It would likely require long-term realignment of funding. If, for instance, you need fewer cops and more outreach workers, you would need to fund that.” 

Papachristos is now working with several U.S. cities, including Chicago and New Orleans, to develop violence prevention programs that look beyond criminal justice to include social workers, community organizers, schools and other support services.  

By mapping gun violence networks and sharing them with teachers, trauma responders and others, Papachristos hopes to make a data-driven case for breaking down these barriers on a large scale. 

“The science is getting clearer and clearer,” he says. “It’s what I’ve been doing for almost 10 years, and we know enough now to do somethingI’m not in the business of designing programs or policies, but I work with people to think about how we can design interventions that are informed by data and research. That’s how I see my role. 

Mapping misconduct in the Chicago police force 

Now, Papachristos is also using network science to understand police misconduct. With help from the Invisible InstitutePapachristos and his colleagues have created a network of all the Chicago police officers who have been accused of misconduct, linking the officers who were accused of misconduct when they were together on the job. 

“We’re trying to figure out what predicts this network, and if police shootings are contagious,” Papachristos says. “We also want to know more about the career trajectories of officers with high misconduct rates.” 

Papachristos network of police misconduct spans 10 years and 7,000 officersPapachristos notes that some officers are falsely accused of misconduct, and most complaints against officers are procedural: failure to fill out a certain form or respond to a call, for instance.  

But then there are some cops who have 20 or more complaints, or 100 or more complaints,” he says.

While the research is ongoing, preliminary data from this work indicate police shootings — and use of force — may follow patterns of contagion similar to neighborhood violence. Additionally, complaints of police misconduct are lowest when an officer new to the force is paired with an officer with a long tenure.

Both gun violence and policing are focus areas for the recently launched Northwestern Neighborhood and Network Initiative (N3). Led by Papachristos and housed within the Institute for Policy Research, N3 is committed to leveraging social connections among people, places and institutions to bring about positive change in communities.


Andrew Papachristos

Andrew Papachristos is a professor of sociology in the Weinberg College of Arts and Sciences. He is also the director of the Northwestern Network and Neighborhood (N3) Initiative and a faculty fellow at the Institute for Policy Research (IPR).

Journalists: View press materials for Andrew Papachristos here.

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