Procedural justice, routine encounters and citizen perceptions of police: main findings from the Queensland Community Engagement Trial (QCET)

Objectives To test, under randomized field trial conditions, the impact of police using the principles of procedural justice during routine encounters with citizens on attitudes towards drink-driving, perceptions of compliance, and their satisfaction with the police. Methods We conducted the first randomized field trial—the ‘Queensland Community Engagement Trial’ (QCET)—to test the impact of police engaging with citizens by operationalizing the key ingredients of procedural justice (neutrality, citizen participation, respect, and trustworthy motives) in a short, high-volume police–citizen encounter. We randomly allocated 60 roadside Random Breath Testing (RBT) operations to control (business-as-usual) and experimental (procedural justice) conditions. Driver surveys were used to measure the key outcomes: attitudes towards drinking and driving, satisfaction with police and perceptions of compliance. Results Citizen perceptions of the encounter revealed that the experimental treatment was delivered as planned. We also found significant differences between the experimental and control groups on all key outcome measures: drivers who received the experimental RBT encounter were 1.24 times more likely to report that their views on drinking and driving had changed than the control group; experimental respondents reported small but higher levels of compliance ( d = .07 ) and satisfaction ( d = .18 ) with police during the encounter than did their control group counterparts. Conclusions Our results show that the way citizens perceive the police can be influenced by the way in which police interact with citizens during routine encounters, and demonstrate the positive benefits of police using the principles of procedural justice. Our study was limited by the use of paper-only surveys and low response rate. We also recognize that the experiment setting (RBT road blocks) is limiting and non-reflective of the wider set of routine police–citizen encounters. Future research should be undertaken, using experimental methods, to replicate our field operationalization of procedural justice in different types of police–citizen encounters.