How Gun Violence Spreads through Networks

Publication date 
January 23, 2017
In a paper published recently in JAMA Internal Medicine, ”Modeling Contagion Through Social Networks to Explain and Predict Gunshot Violence in Chicago, 2006 to 2014”, Andrew Papachristos and fellow researchers Ben Green and Thibaut Horel present their findings that gun violence mimics the process of an epidemic. The question proposed by the researchers focuses on the probability of a person becoming the subject of firearm violence and the extent to which subjects can be predicted.
The study was conducted among a social network of arrested individuals, most of whom were black and male, from Chicago, Illinois. Results of the study demonstrate that the subjects of gun violence in the city were shot an average of 125 days after “the infector” was targeted. “The infector” is defined as “the person most responsible for exposing the subject to gunshot violence.” According to the researchers, social contagion accounted for 63.1% of the 11,123 occurrences of gun violence recorded in Chicago between 2006 and 2014.
Papachristos and co-authors explain that the significance of their study is the change by which gun violence prevention can be approached. Their models, which account for social contagion and demographics, predicted the victims of future gun violence better than exclusively demographics-based models. Acknowledging the epidemic-like nature of the spread of gun-related attacks can lead to a greater potential in reducing the number of shootings in a city.

Media coverage:

  • “Study Says Gun Violence Should Be Treated As a Public Health Crisis” NPR 
  • “Yale Study Finds that Gun Violence is a ‘Contagious’ Social Epidemic” Yale News
  • “Yale Study: Epidemic of Gun Violence is ‘Contagious’ ” New Haven Register
  • “Yale Study Models Gun Violence as a Social Epidemic” Yale Daily News
  • “Gunshot Wounds Are Contagious; Bullets Spread like the Flu, Study Finds” Arstechnica