Unexpected events during survey design and trust in the police: a systematic review

Objectives: The current review has two aims: (1) to synthesize the impact of unexpected events on trust in police across different contexts and types of events, and (2) to evaluate the methodological characteristics of each study with attention to the assumptions for causal inference. Methods: We conducted a pre-registered narrative systematic review on 12 independent studies. Results: Studies closely adhering to causal inference assumption checks (i.e., excludability and ignorability) find significant changes in trust in police following incidents of police (non) violence and protest. Still, excludability is assessed and addressed less rigorously than ignorability in the included studies. Conclusion: Regarding the procedural justice framework, this provides some causal evidence that vicarious (positive and negative) experiences can shape short-term assessments of public trust in police. We furthermore highlight issues related to design and power, statistical conclusion validity, and the evaluation of assumptions to detect threats to internal validity.