Quantifying Disparities in Urban Firearm Violence by Race and Place in Philadelphia, Pennsylvania: A Cartographic Study.

Abstract

To describe variability in the burden of firearm violence by race, income, and place in an urban context. We used Philadelphia Police Department data from 2013 to 2014 to calculate firearm assault rates within census block groups for both victim residence and event locations, stratifying by race and block group income. We used cartographic modeling to determine variations in incidence of firearm assault by race, neighborhood income, and place. The overall rate of firearm assault was 5.0 times higher (95% confidence interval [CI] = 4.5, 5.6) for Black people compared with White people. Firearm assault rates were higher among Black people across all victim residence incomes. Relative risk of firearm assault reached 15.8 times higher (95% CI = 10.7, 23.2) for Black residents in the highest-income block groups when compared with high-income White individuals. Firearm assault events tended to occur in low-income areas and were concentrated in several "hot spot" locations with high proportions of Black residents. Profound disparity in exposure to firearm violence by race and place exists in Philadelphia. Black people were substantially more likely than White people to sustain firearm assault, regardless of neighborhood income.