Body-worn cameras and arrest: Zooming in on disaggregated metrics and possible unintended consequences

Purpose: This study sought to assess the effects of body-worn cameras (BWCs) on arrest in the Chicago Police Department (CPD). It builds on the small number of studies that have explored the BWC-arrest nexus through its focus on outcome measures disaggregated by initial arrest category to see if there is additional specificity to the relationship. Methods: This study uses a quasi-experimental design and propensity score matching (PSM) to compare similar groups of spatial units - police patrol districts - in the CPD over a 30-month study period. It also uses multivariate methods to assess whether difference scores in various types of arrest changed significantly over time after the introduction of BWCs. Results: The results showed that in the BWC districts, arrests for misdemeanor marijuana possession increased as time increased (i.e. the difference scores became less negative). This tendency did not appear in a control group of districts. For all other categories of arrest, change occurred at similar rates in the BWC-and control districts. Conclusion: An upward trend over time in arrests for marijuana possession after the introduction of BWCs could be an unintended consequence that may undermine benefits a department and community may gain from reductions in use of force and complaints.