A realist review on the police use of stop and search powers

Proponents of police use of stop and search powers argue that they are essential to prevent crime and improve public safety. However, there is increasing evidence that stop and search generates a range of adverse effects, including poor mental health outcomes. Missing from these debates is an understanding of the mechanisms that drive the practice and why and in what circumstances it can lead to negative outcomes. To fill this gap, a realist review was conducted on police use of stop and search of people in public places. Searches of academic and grey literature from January 2000 to December 2022 identified 206 relevant studies from 21 countries. The review identified a range of contextual factors, mechanisms and moderators that affect stop and search outcomes in developing a programme theory of stop and search. The review shows that police stop and search practice can be shaped by contextual factors, such as political climate, organisational priorities and the characteristics of where stop and search is deployed and who is stopped. The review further distinguishes four different mechanisms for stop and search, including three commonly stated justifications for stop and search (detection, deterrence and disruption) and one mechanism increasingly associated with negative outcomes (surveillance). A range of outcomes are also discussed, including crime reduction, attitudes about the police and mental health outcomes. The review brings to the fore contexts and mechanisms that are more (and less) likely to cause negative outcomes from stop and search: a vital contribution to more evidence-informed and just policy and practice.