Police‐initiated diversion for youth to prevent future delinquent behavior: a systematic review
Authors: Wilson David B. , Brennan Iain , Olaghere Ajima 
Published: June 2018

This Campbell systematic review examines the effects police‐initiated diversion programs on delinquent behavior, compared to traditional system processing. The review summarizes evidence from nineteen high‐quality studies, including 13 randomized controlled trials and six quasi‐experimental studies.This review includes studies that evaluated the effects of police‐led diversionary practices compared to traditional processing for youth under 18 years of age. We identified a total of 14 manuscripts representing 19 evaluations. Of these 19 evaluations, 13 used randomized controlled designs (random assignment to conditions) and 6 used quasi‐experimental designs (no random assignment to conditions). Many of these designs included two or more diversionary conditions compared to a common control (traditional processing) producing 31 treatment‐comparison contrasts for analysis. These studies were conducted between 1973 and 2011, inclusively. Most were conducted in the USA (11) with the remaining conducted in Canada (4), Australia (2), and the UK (2).The general pattern of evidence is positive, suggesting that police‐led diversion reduces the future delinquent behavior of low‐risk youth relative to traditional processing. Assuming a 50 percent reoffending rate for the traditional processing condition, the results suggest a reoffending rate of roughly 44 percent for the diverted youth. This overall benefit of diversion holds for the random assignment studies judged to be free from any obvious risks of bias. No meaningful differences were found across types of diversionary programs. Furthermore, we found no evidence to suggest these findings suffer from publication selection bias.Plain language summaryPolice‐led diversion of low‐risk youth reduces their future contact with the justice systemPolice‐led diversion of low‐risk youth who come into contact with the justice system is more effective in reducing a youth's future contact with the justice system compared to traditional processing.What is this review about?Youth misconduct and misbehavior is a normal part of adolescence and that misbehavior sometimes crosses the line from disruptive or problematic to delinquent. Nationally representative surveys of youth in the USA have indicated that minor delinquent behavior is normative, particularly for boys. The normative nature of minor delinquent behavior raises the question of how police should respond to minor delinquent behavior in a way that is corrective, but also avoids involving the youth in the criminal justice system beyond what will be effective in reducing future misbehavior.Police diversion schemes are a collection of strategies police can apply as an alternative to court processing of youth. Diversion as an option is popular among law enforcement officers, as it provides an option between ignoring youth engaged in minor wrongdoing and formally charging such youth with a crime. Police‐led diversion has the potential to reduce reoffending by limiting the exposure of low‐risk youth to potentially harmful effects of engagement with the criminal justice system.What is the aim of this review?This Campbell systematic review examines the effects police‐initiated diversion programs on delinquent behavior, compared to traditional system processing. The review summarizes evidence from nineteen high‐quality studies, including 13 randomized controlled trials and six quasi‐experimental studies. This review examined whether police‐led diversion and traditional processing of youth have different effects on rates of official delinquency.What are the main findings of this review?This review includes studies that evaluated the effects of police‐led diversionary practices compared to traditional processing for youth under 18 years of age. We identified a total of 14 manuscripts representing 19 evaluations. Of these 19 evaluations, 13 used randomized controlled designs (random assignment to conditions) and 6 used quasi‐experimental designs (no random assignment to conditions). Many of these designs included two or more diversionary conditions compared to a common control (traditional processing) producing 31 treatment‐comparison contrasts for analysis. These studies were conducted between 1973 and 2011, inclusively. Most were conducted in the USA (11) with the remaining conducted in Canada (4), Australia (2), and the UK (2).The general pattern of evidence is positive, suggesting that police‐led diversion reduces the future delinquent behavior of low‐risk youth relative to traditional processing. Assuming a 50 percent reoffending rate for the traditional processing condition, the results suggest a reoffending rate of roughly 44 percent for the diverted youth. This overall benefit of diversion holds for the random assignment studies judged to be free from any obvious risks of bias. No meaningful differences were found across types of diversionary programs. Furthermore, we found no evidence to suggest these findings suffer from publication selection bias.What do the findings of this review mean?The findings from this systematic review support the use of police‐led diversion for low‐risk youth with limited or no prior involvement with the juvenile justice system. Thus, police departments and policy‐makers should consider diversionary programs as part of the mix of solutions for addressing youth crime.Many of the studies included in the review were conducted in the 1970s and 1980s. Newer high quality studies are needed to ensure that the findings still hold for contemporary juvenile justice contexts. Additional studies are also needed outside of the USA for this same reason. Finally, we recommend that research explore the usefulness of diversion for low‐risk adult offenders.How up‐to‐date is this review?The search for eligible studies was completed in January of 2017, so only studies identifiable through January 2017 were included. This Campbell systematic review was published in May 2018.Executive summary/AbstractBackgroundOverly punitive responses to youth misconduct may have the unintended consequence of increasing the likelihood of future delinquency; yet, overly lenient responses may fail to serve as a corrective for the misbehavior. Police diversion schemes are a collection of strategies police can apply as an alternative to court processing of youth. Police‐initiated diversion schemes aim to reduce reoffending by steering youth away from deeper penetration into the criminal justice system and by providing an alternative intervention that can help youth address psychosocial development or other needs that contribute to their problem behavior.ObjectivesThe objective of this review was to synthesize the evidence on the effectiveness of pre‐court interventions involving police warning or counseling and release, and cautioning schemes in reducing delinquent behavior.Search methodsA combination of 26 databases and websites were searched. References of relevant reviews were also scanned to identify studies. We also consulted with experts in the field. Searches were executed by two reviewers and conducted between August 2016 and January 2017.Selection criteriaOnly experimental and quasi‐experimental designs were eligible for this review. All quasi‐experimental designs must have had a comparison group similar to the police diversion intervention group with respect to demographic characteristics and prior involvement in delinquent behavior (i.e., at similar risk for future delinquent behavior). Additionally, studies must have included youth participants between 12 and 17 years of age who either underwent traditional system processing or were diverted from court processing through a police‐led diversion program. Studies were also eligible if delinquency‐related outcomes, including official and non‐official (self‐report or third‐party reporting) measures of delinquency were reported.Data collection and analysisThis study used meta‐analysis to synthesize results across studies. This method involved systematic coding of study features and conversion of study findings into effect sizes reflecting the direction and magnitude of any police‐led diversion effect. There were 19 independent evaluations across the 14 primary documents coded for this review. From this, we coded 67 effect sizes of delinquent behavior post diversion across 31 diversion‐traditional processing comparisons. We analyzed these comparisons using two approaches. The first approach selected a single effect size per comparison based on a decision rule and the second used all 67 effect sizes, nesting these within comparison condition and evaluation design.ResultsThe general pattern of evidence is positive, suggesting that police‐led diversion modestly reduces future delinquent behavior of low‐risk youth relative to traditional processing.Authors' conclusionsThe findings from this systematic review support the use of police‐led diversion for low‐risk youth with limited or no prior involvement with the juvenile justice system. Thus, police departments and policy‐makers should consider diversionary programs as part of the mix of solutions for addressing youth crime.