Focus of the intervention
Police-led pre-charge diversion models are an alternative response to traditional court procedures for young offenders under 18 years of age with limited or no prior involvement with the criminal justice system.
Diversion occurs prior to charging. It involves the police imposing sanctions such as a caution, restorative caution, final warning and reprimand.
Pre-charge diversion models typically occur in the form of either:
- diversion only
- diversion with referral to services (internal or external to criminal justice system)
- diversion with police-led restorative justice
These models start before the imposition of charges to:
- avoid labelling young people as offenders
- avoid exposing them to the formal criminal justice system
- provide a mechanism of forgiveness and non-stigmatisation for reintegration purposes
This narrative is based on one meta-analytic review covering 19 studies. Eleven of the primary studies in the meta-analysis were based on evidence from the USA, four from Australia, two from Canada and two from the UK.
Effect – how effective is it?
Overall, the evidence suggests that police-led pre-charge diversion models for young offenders has reduced reoffending.
The meta-analysis found that police-led pre-charge diversion models for young offenders led to a modest but statistically significant 6% decrease in reoffending compared to those who received standard formal sentencing.
Assuming a 50% reoffending rate for those who received traditional processing, the average reoffending rate for those receiving pre-charge diversion was 44%.
Across the 19 studies, 31 individual comparisons of diversion versus traditional processing were identified as some studies included two or more diversion conditions compared to a single control condition.
Eight studies found that police-led pre-charge diversion led to a statistically significant decrease in reoffending, none of the studies reported an increase in reoffending and 23 found no evidence of effect compared to traditional processing.
When the results are combined, the increased sample size provides a more precise estimate and overall statistically significant result.
After analysing the effect sizes by the quality of study methodology, the results from both the higher-quality study designs (random assignment studies) and those of lower quality (quasi-experimental studies) show a decrease in reoffending for those who received pre-charge diversion compared to traditional processing.
In both cases, the effect is not statistically significant, but this is unsurprising given the small number of studies and the relatively modest overall result.
Again, when the results of the two types of study design are combined, a result with greater precision is produced.
How strong is the evidence?
The review was sufficiently systematic that many forms of bias that could influence the conclusions can be ruled out.
The evidence is taken from one meta-analytic review covering 19 studies. The studies demonstrated a high quality design in terms of having a transparent and well-designed search strategy, featuring a valid statistical analysis, sufficiently assessing publication bias, the risk of bias in analysis and considering the way outcomes are measured and combined.
However, the review did not sufficiently consider the influence of statistical outliers and did not appear to use an appropriate weighting scheme to account for less rigorous study designs.
Mechanism – how does it work?
Police-led pre-charge diversion models for young offenders are assumed to reduce reoffending by:
- reducing the exposure of young offenders to deviant peer groups within the criminal justice system who may transmit negative values, attitudes or techniques or motivate deviant behaviour
- reducing the potential for young offenders to become labelled as delinquents, which might encourage offenders to develop expectations for offending in the future
- providing a mechanism of forgiveness and non-stigmatisation, therefore allowing a young offender to successfully reintegrate into society
- signposting young offenders to services that may assist with the prevention of further deviant behaviour
However, these assumptions were not empirically tested. Future research should consider testing these potential change mechanisms.
Moderators – in which contexts does it work best?
The review noted that the effect of the intervention might function according to a number of contextual conditions.
- Intervention type – the review did not find a statistically significant difference in terms of reoffending between the three types of diversion models. These are diversion only (for example, caution) (13 studies), diversion with referral to services (internal or external to the criminal justice system) (14 studies), or diversion with police-led restorative justice (four studies).
- Intervention setting – the review did not find a statistically significant difference between the effectiveness of the intervention in different countries. The effect of the intervention did not vary depending on whether the study was conducted in the USA or other countries (Canada, Australia or the UK).
Implementation – what can be said about implementing this initiative?
The review did not include detailed information relating to implementation of diversion models in the included studies, however it noted a number of elements specific to particular models.
- Traditional police cautioning schemes include a police officer, the young person in question, and their parents or guardian at the minimum. Victims are not involved and police officers do not routinely receive training, but explain the legal and social consequences of continued antisocial or criminal behaviour.
- Variants of the above scheme – such as caution plus and restorative cautioning – involve additional elements. For example, the involvement of a script to structure discussion between the young person and affected parties, and presence of the victim in the case of restorative cautioning or conferencing.
- The final warning and reprimand scheme involves an assessment-based approach evaluating the seriousness of the offence. The gravity of the offence determines whether the young person receives a reprimand or final warning with referral for multi-agency assessment and placement in a behavioural treatment program.
Economic considerations – how much might it cost?
The review did not mention the costs or benefits of diversion models. No formal economic analysis was provided.
- Many of the primary studies were conducted several decades ago – the timeframe covered in the studies is 1973 to 2011. Thirteen studies were conducted pre-2000. There are too few studies conducted in the last decade to be confident that the positive results will hold for contemporary youth justice.
- The majority of the evidence is based in the USA, so caution should be taken when applying to other geographical contexts.
- There is limited information about the content and implementation of police-led pre-charge diversion models. As suggested by the review, the underlying message delivered through diversion models (for example, a 'last chance opportunity' message compared to a 'helping out' message) might have different effects on reoffending rates.
There is evidence that police-led pre-charge diversion models for low-risk young offenders can modestly reduce crime overall.
Diversion models are expected to prevent young offenders from being exposed to deviant peers in the criminal system and from being labelled as delinquents, which can increase the likelihood of reoffending.
The review concluded that there were no statistically significant differences in terms of reoffending between different diversion models or countries of study.
Further research is needed to examine the implementation and economic issues surrounding police-led pre-charge diversion for young offenders.
Wilson, D.B., Brennan, I. and Olaghere, A. (2018), Police‐initiated diversion for youth to prevent future delinquent behavior: a systematic review. Campbell Systematic Reviews, 14: 1-88. doi:10.4073/csr.2018.5
Summary prepared by
This narrative was prepared by the College of Policing and was co-funded by the College of Policing and the Economic and Social Research Council (ESRC). ESRC grant title: 'University Consortium for Evidence-Based Crime Reduction'. Grant reference: ES/L007223/1.