Space-Time Association between Gunshot Detection Alerts, Calls for Service, and Police Enforcement in Chicago: Differences Across Citizen Race and Incident Type

Abstract

Abstract Objectives This study explores the level to which Gunshot Detection Technology (GDT) leads to increased arrests and stops as compared to shots fired calls for service (CFS) in Chicago, Illinois. Methods A two-process Knox test and point process test are applied to measure the level to which GDT alerts and CFS cluster with arrests and stops in space and time. Both tests are first applied to the aggregate arrest and stops data. We then disaggregate arrests and stops by type as well as suspect race/ethnicity to measure any disproportionate effects across GDT and CFS. Results Both GDT alerts and CFS are significantly associated with arrests and stops occurring in close spatial and temporal proximity. The relative effect of GDT and CFS was consistent across race in the majority of instances. The small number of instances with disparate effects did not exhibit any clear patterning. For some racial groups and arrest/stop types, GDT was associated with heightened enforcement while CFS had a null effect, with the opposite relationship observed for other racial groups and arrest/stop types. Conclusions Overall, the results indicate that GDT systems may not generate racial disparities in arrests and stops above and beyond what results from the standard police response to gunfire. Racial disparities resulting from police responses to reported gunfire likely relate to aspects of the reporting and dispatch processes generally rather than as they relate specifically to GDT.