Police stops are associated with reductions in crime but also a broad range of negative individual-level outcomes
Police stop interventions produce meaningful and significant reductions in crime without evidence of spatial displacement. However, people subject to stops are associated with significantly less desirable mental and physical health outcomes, attitudes toward police, and self-reported crime/delinquency. For some outcome measures, the negative effects of pedestrian stops are considerably more pronounced for youth, though the data did not permit a comparison of individual effects by race.
What is this review about?
Police stops have become one of the most controversial yet widely-used crime prevention strategies in modern policing. This intervention involves the police-initiated stop of an individual (or group of individuals) on the street, for the purpose of investigation and/or questioning. Police stops have been commonly used as a tactic to combat violent and gun-related crime.
The current review assesses the effect of police stops (used interchangeably here with “pedestrian stops”) on both place-based and person-based outcomes, including crime, spatial displacement, mental health, physical health, attitudes toward the police, and self-reported crime/delinquency.
What is the aim of this review?
This Campbell systematic review examines the effects of police-initiated pedestrian stops on both place-based and person-based outcomes. It synthesizes results from 40 studies across six outcome groupings. Studies were predominately conducted in the USA.
What studies are included?
Forty studies published between 1970-2021 are included in this review. Eligibility was limited to experimental and quasi-experimental studies with a treatment group of people or places that experienced police stops and a control group of people or places that did not experience police stops (or experienced a lower dosage of stops).
Studies focusing only on police-initiated traffic stops were excluded from this review. Only one eligible study was a randomized controlled trial, 33 studies were conducted in the USA, and seven were conducted in Europe.
What are the main findings of this review?
Police stop interventions lead to significant reductions in area-level crime with evidence of a diffusion of crime control benefits to nearby areas. However, methodological difficulties limit the strength of the causal inferences derived from these studies; further research is needed.
Individuals stopped by police are associated with significantly higher odds of both mental and physical health issues, significantly more negative attitudes toward the police, and elevated levels of self-reported crime/delinquency. The impact of a direct stop experience on mental health issues is also considerably larger for youth, compared to adults.
Despite this finding, place-based studies incorporating community surveys suggest that stop interventions do not impact community-level attitudes toward the police, and thus the negative effects of these interventions may be limited to the individuals directly experiencing them.
The findings of this review should be interpreted with caution, however, as only one randomized experiment assessing crime prevention outcomes was identified, and person-based studies were often unable to establish temporal ordering between the treatment and outcome measures.
What do the findings of the review mean?
Policing efforts focused on high-volume pedestrian stops are likely to reduce crime but may do so at the cost of negative health outcomes, negative attitudes toward the police, and higher levels of delinquency for individuals subject to the intervention. Given the net-widening effects of pedestrian stops (i.e., low proportions of stops lead to arrests or weapon seizures), these interventions may produce more harm than good. Police agencies should carefully weigh the potential benefits and harms associated with these interventions.
Furthermore, recent reviews on tactics such as hot spots policing and problem-oriented policing have demonstrated larger reductions in crime without similar backfire effects. The evidence-base for these tactics is also of considerably higher methodological rigor, generating stronger conclusions regarding program effectiveness. While it is possible that police agencies can mitigate the negative effects of pedestrian stops through a focus on improving officer conduct during police-citizen encounters, this review is unable to provide evidence of this effect.
How up-to-date is this review?
The authors of this review employed search strategies intended to capture studies through December 2021.