Purpose – To determine whether neighborhood disorder changes an individual's risk of being injured with a firearm.

Methods – A one-year, population-based, case-control study set in Philadelphia.  Information from residents who were shot (the cases) was collected from a dozen local, state, and national data partners.  Based on this information, an age, race, and sex-matched resident was randomly selected (the controls) and asked their location at the time of each shooting.  Neighborhoods were defined as 1,801 block groups and disorder was separated into both social and physical dimensions.  Odds and 95% confidence intervals were calculated with conditional logistic regression.

Results – A total of 472 cases and 485 controls were used for analysis.  Shooting cases were located in neighborhoods with significantly higher levels of both physical (Map 1) and social disorder (Map 2) (p<0.001) and the risk of being shot increased significantly and monotonically with neighborhood disorder (p<0.001).  The most socially disordered neighborhoods were 6.96 [2.49, 19.46] times more likely and the most physically disordered neighborhoods were 3.97 [1.40, 11.26] times more likely to experience an interpersonal shooting.  The most socially disordered neighborhoods were 1.15 [0.21, 6.19] times more likely and the most physically disordered neighborhoods were 1.08 [0.17, 5.52] times more likely to experience a self-directed shooting.

Conclusions – Social disorder was more strongly associated with increased interpersonal shooting risk than physical disorder.  Similar associations were not found for self-directed shootings.  Efforts to modify neighborhoods with identifiable characteristics of social and then physical disorder will go far to prevent interpersonal shootings.