Effect of awareness and notification of body-worn cameras on procedural justice, police legitimacy, cooperation, and compliance: Findings from a randomized controlled trial

Objectives The study examined the effects of awareness and notification of body-worn cameras (BWCs) on encounter-based citizen perceptions including procedural justice, police lawfulness, compliance with police, and global-level perceptions including police legitimacy, cooperation, and compliance with law. Methods A vignette-based cluster randomized controlled trial was conducted. As a cluster, participants were randomly selected and then randomly assigned to one of the four conditions (non-BWC, unawareness of BWC, awareness of BWC, and notification of BWC). Participants in the experimental conditions (i.e., unawareness of BWC, awareness of BWC, and notification of BWC) viewed a video of a real traffic stop in which the officer used a BWC. The data were obtained from a survey about participants' perceptions. A one-way ANOVA test for bivariate analysis and a hierarchical generalized linear model for multivariate analysis were conducted. Results Compared with the control condition, the three experimental conditions significantly improved encounter-based citizen perceptions. Compared with unawareness of BWC, notification of BWC significantly improved the perceptions of procedural justice and police lawfulness, while awareness of BWC significantly improved the perceptions of police lawfulness. Conclusions BWC awareness improves citizen encounter-based perceptions. Police should notify citizens of the use of BWCs to increase the effectiveness of BWCs.