Homicide as Infectious Disease: Using Public Health Methods to Investigate the Diffusion of Homicide

This study examined the spatial and temporal movement of homicide in Newark, New Jersey from January 1982 through September 2008. We hypothesized that homicide would diffuse in a similar process to an infectious disease with firearms and gangs operating as the infectious agents. A total of 2,366 homicide incidents were analyzed using SaTScan v.9.0, a cluster detection software. The results revealed spatio-temporal patterns of expansion diffusion: overall, firearm and gang homicide clusters in Newark evolved from a common area in the center of the city and spread southward and westward over the course of two decades. This pattern of movement has implications in regards to the susceptibility of populations to homicide, particularly because northern and eastern Newark remained largely immune to homicide clusters. The theoretical and practical implications of the findings, as well as recommendations for future research, are discussed.