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Police-initiated diversion for youth to prevent future delinquent behavior

Additional Info

  • Authors: David B. Wilson, Iain Brennan, Ajima Olaghere
  • Published date: 2018-06-01
  • Coordinating group(s): Crime and Justice
  • Type of document: Title, Protocol, Review, Plain language summary
  • See the full review:

About this systematic 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.

What are the main results?

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.


Overly 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.


The 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 methods

A 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 criteria

Only 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 analysis

This 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.


The 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’ conclusions

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.

See the full review

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