Providing offenders with support from a more experienced person, to improve their knowledge, skills, ability or experience.
First published
Effect scale Quality of evidence
Effect Impact on crime Mechanism How it works Moderator Where it works Implementation How to do it Economic cost
Overall reduction, some rises

Very strong




Focus of the intervention

Mentoring involves interactions between two individuals over an extended period of time and an inequality of experience or knowledge between the mentor and mentee – with the mentor possessing the greater share.

The idea is that the mentee is in a position to imitate and benefit from the knowledge, skill, ability, or experience of the mentor.

The mentor may provide practical assistance, such as with job applications, teaching or training, as well as emotional support for the mentee to help increase self-esteem and confidence.

Mentoring may be between a youth and an adult, or between peers.

This narrative is based on one review of 46 studies that focused on juvenile delinquents and a second review based on 18 studies that focused on general offending.

A third review based on eight studies of mentoring provides information in the implementation and economics sections.

The crime outcomes measured in the reviews were delinquency (for example, anti-social behaviour) and reoffending.

Effect – how effective is it?

Overall, the evidence suggests that mentoring has reduced crime, but there is some evidence that it has increased crime.

The overall evidence comes from Review one, based on 46 studies. A meta-analysis of outcomes from 25 of the 46 studies showed a statistically significant reduction in reoffending among participants who received mentoring compared to those who did not.

While 14 of these 25 studies showed a significant reduction in reoffending, three studies showed a significant increase. The other eight studies showed no significant effect on reoffending.

Review one also tested to see if there was a correlation between the effect size and study methodology, finding no statistically significant effect. Studies of arguably weaker methodology found similar levels of reoffending to those of stronger methodologies.

The Review also found no significant difference between the level of reoffending of participants and whether mentoring was carried out as a stand-alone intervention or as part of a package.

This was in contrast to Review two, which found that mentoring was significantly more effective when implemented as part of a suite of interventions, rather than alone.

How strong is the evidence?

The Review was sufficiently systematic that most forms of bias that could influence the study conclusions can be ruled out. 

Review one considered many elements of validity, conducted relevant statistical analyses and used quality assurance to ensure the accuracy of the information collected from primary studies.

It also took into account the potential effects of publication bias, and only combined studies of similar methodological quality.

The Review also took into account the possible effect of statistical outliers.

Mechanism – how does it work?

Review one noted that mentoring may help to reduce crime by diverting individuals from criminal activities and attitudes, as well as by fostering healthy or positive development.

Review one identifies four processes as central to mentoring in order to encourage this healthy development.

  • The mentee identifies with the mentor, which can help with motivation and behaviour.
  • Providing information or teaching to help the mentee manage social, educational, legal, family and peer challenges.
  • Advocacy for the mentee in various systems and settings.
  • Emotional support and friendship to promote self-efficacy, confidence, and sense of self-worth.

The Review tested whether certain components of mentoring programmes had a positive effect in reducing crime, finding that significant reductions were found when advocacy and emotional support components were present.

Review two noted that having a mentor might reduce the likelihood of reoffending by providing direct assistance (for example, helping fill in job applications) and indirect support (for example, acting as a positive role model).

Echoing Review one, it also noted that the time spent with the mentor might reduce the opportunity that the mentee has to offend or might help to break up previously established delinquent networks.

Review two also noted that mentoring is usually intended as method of both reducing reoffending and increasing positive life outcomes, such as greater levels of education, training and employment.

In a test of the relationship between mentor and mentee, Review two found that having a longer duration per contact saw significantly greater reductions in reoffending than programmes with shorter durations of contact.

The review suggested that longer durations of contact allow a stronger relationship to be built between mentor and mentee.

Moderators – in which contexts does it work best?

Review one found that mentoring produced a statistically significant reduction in delinquency, aggression and drug use, and a significantly positive effect on academic achievement for mentees.

The Review also tested to see if a number of key features had an effect on reoffending rates, including:

  • selectivity in deciding which participants to include (high risk versus universal or no selectivity) 
  • explicit attention to the presence of four key processes – modelling, emotional support, advocacy and teaching
  • whether or not mentoring was a stand-alone approach or was undertaken along with other components
  • motivation of the mentors in participating
  • the extent to which quality of work and fidelity were assessed or emphasised

It was found that only the motivation of the mentor had significance. Reductions in crime were significantly larger when mentor motivation was based on the mentor’s professional development.

Review two focused on adults and young people, so was able to test whether there was a difference in the efficacy of mentoring by age.

It found that mentoring had a more desirable but not statistically significant effect on reoffending for younger as opposed to older mentees (although exact age ranges were not specified).

However, when testing at which point in the criminal justice process mentoring worked best, it was found that the only time mentoring had a significant benefit on reoffending was if it was conducted pre-sentence.

When mentees were chosen for being at risk of offending behaviour or were post-sentence, mentoring had no statistically significant effect on reoffending.  

Implementation – what can be said about implementing this initiative?

Review one did not find any training, implementation or dosage parameters that can be consistently identified as important in mentoring programmes.

There were also few indications of what is considered essential or critical for mentoring, or helpful in distinguishing mentoring from other models of supportive relationships and approaches.

However, mentoring was defined by four characteristics.

  • Interaction between two individuals over an extended period of time.
  • Inequality of experience, knowledge or power between the mentor and mentee (recipient), with the mentor possessing the greater share.
  • The mentee being in a position to imitate and benefit from the knowledge, skill, ability or experience of the mentor.
  • The absence of the role inequality that typifies other helping relationships and is marked by professional training, certification or predetermined status differences, such as parent-child or teacher-student relationships.

Further analyses suggested that mentoring may be particularly valuable for those at risk of or already involved in delinquency or related issues.

Review two suggests that the mentor should provide guidance, advice and encouragement that would help to develop the competence and character of the mentee.

The mentee is usually perceived to be at risk of offending behaviour for various reasons, including individual factors (for example, disruptive behaviour in school, offending, substance abuse) and/or social circumstances (for example, lone-parent family, socially excluded).

Review two also noted a number of implementation factors that were associated with stronger desirable effects on reoffending.

Mentoring interventions involving at least weekly contact between mentor and mentee, and those where the average duration time per contact between mentor and mentee was longer, tended to be more successful than less intensive and less frequent interventions.

The Review found that by itself, mentoring had little effect on reoffending. Only when mentoring was offered alongside other interventions (such as ensuring employment or education) was there a desirable impact on reoffending.

Also, mentoring was more successful with persons arrested by the police rather than young people at risk of offending or those on probation (although numbers in this last group were small).

Any beneficial impact of mentoring on reoffending was limited to the time period that mentoring was being offered.

The authors go on to state that these results suggest that mentoring could be implemented as a valuable component of a long-term intervention strategy with people who have been in contact with the police, but do not have a long criminal history.

Review three gave some specific information about the inputs of different mentoring programmes, which varied significantly.

One programme required mentors to have 16 to 20 hours of training and instruction before helping mentees.

Another programme saw mentors with a caseload of approximately ten young people each with 50 hours of face-to-face contact over seven months.

A further programme, which mentored young people after release from custody, required seven contacts with the mentor over 12 to 18 months.

A further study was much more intense, requiring two to six hours of contact per week between mentors and mentees during the first year.

Economic considerations – how much might it cost?

Review three was the only review to provide any information on the costs or benefits of mentoring programmes. All financial information was only available at individual study level and no synthesis was attempted due to a lack of information from the studies in the review.

One study based in hospital emergency departments in California, USA noted that mentors each received a total payment of $240 for their time, including time spent on training and mentoring.

Another study based in Australia calculated the programme costs, including staff time, office space, transport, and other administrative costs. They also included volunteer time, estimated at AUD$16 per hour.

They calculated the annual cost for each mentee in 2004 as AUD $6,264. The cost of mentoring 2,200 vulnerable, ‘at risk’ young people over a number of years was estimated at AUD $40 million, while the associated costs of their predicted adult offending was AUD $3.3 billion.

Therefore, the mentoring programme would be cost effective if it prevented only 1.3% of mentees from offending.

General considerations

  • There is often limited description of the content of mentoring programmes and substantial variation in what is included as part of these programmes. This means it can be difficult to understand what contributes to any successes or failures of specific mentoring interventions.


Overall, the evidence suggests that mentoring has reduced crime, but there is some evidence that it has increased crime.

A significant reduction in reoffending was seen amongst participants of mentoring programmes compared to those who were not on any programmes.

Mentoring is based on encouraging healthy development of mentees, providing them with direct and indirect support, and potentially reducing the time they can engage in criminal activities.

Mentoring programmes where the mentor and mentee meet more often and spend more time together produced the highest reductions in offending behaviour.

The evidence suggests that mentoring could be a valuable diversionary tool if it is used as a component of a long-term intervention strategy, particularly with people who have been in contact with the police but do not have a long criminal history.


Review two

Quality of evidence
Mechanism How it works Moderator Where it works Implementation How to do it Economic cost What it costs




No information


Jolliffe, D. and Farrington, D. P. (2008) 'The Influence of Mentoring on Reoffending', Swedish National Council for Crime Prevention

Review three

Quality of evidence
Mechanism How it works Moderator Where it works Implementation How to do it Economic cost What it costs




No information


Summary prepared by

This narrative was prepared by UCL Jill Dando Institute 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.

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