Mentoring Interventions to Affect Juvenile Delinquency and Associated Problems: A Systematic Review

Mentoring is one of the most commonly used interventions to prevent, divert, and remediate youth engaged in, or thought to be at risk for delinquent behavior, school failure, aggression, or other antisocial behavior. In this update we report on a meta‐analytic review of selective and indicated mentoring interventions that have been evaluated for their effects on delinquency outcomes for youth (e.g., arrest or conviction as a delinquent, self‐reported involvement) and key associated outcomes (aggression, drug use, academic functioning). Of 164 identified studies published between 1970 and 2011, 46 met criteria for inclusion. Mean effects sizes were significant and positive for delinquency and academic functioning with trends (marginal significance level) for aggression and drug use. Effect sizes were modest by Cohen's differentiation. However, there was heterogeneity in effect sizes across studies for each outcome. The obtained patterns of effects suggest mentoring may be valuable for those at‐risk or already involved in delinquency and for associated outcomes. Comparison of study design (randomised control trial (RCT) or quasi‐experimental (QE)) did not show significant differences in effects. Moderator analysis showed larger effects when professional development was the motivation of the mentors for involvement, but not for basis of inclusion of participants (environmental vs. person basis of risk), presence of other interventions, or assessment of quality of fidelity. We also undertook the first systematic evaluation of key processes that seem to define how mentoring may aid youth (e.g. identification/modeling, teaching, emotional support, advocacy) to see if these related to effects. Based on studies we could code for the presence or absence of each as part of the program effort, analyses found stronger effects when emotional support and advocacy were emphasized. These results suggest mentoring is as effective for high‐risk youth in relation to delinquency as many other preventive and treatment approaches and that emphasis on some theorized key processes may be more valuable than others. However, the collected set of studies is less informative than expected with quite limited specification about what comprised the mentoring program and implementation features. The juxtaposition of popular interest in mentoring and empirical evidence of benefits with the limited reporting of important features of the interventions is seen highlights the importance of more careful and extensive evaluations. Including features to understand testing of selection basis, program organization and features, implementation variations, and theorized processes for effects will greatly improve understanding of this intervention. All are essential to guide effective practice of this popular and very promising approach. Synopsis Mentoring is one of the most commonly used interventions to prevent, divert, and remediate youth engaged in, or thought to be at risk for delinquent behavior, school failure, aggression, or other antisocial behavior. In this update we report on a meta‐analytic review of selective and indicated mentoring interventions that have been evaluated for their effects on delinquency outcomes for youth (e.g., arrest or conviction as a delinquent, self‐reported involvement) and key associated outcomes (aggression, drug use, academic functioning). Of 164 identified studies published between 1970 and 2011, 46 met criteria for inclusion. Mean effects sizes were significant and positive for delinquency and academic functioning with trends (marginal significance level) for aggression and drug use. Effect sizes were modest by Cohen's differentiation. However, there was heterogeneity in effect sizes across studies for each outcome. The obtained patterns of effects suggest mentoring may be valuable for those at‐risk or already involved in delinquency and for associated outcomes. Comparison of study design (RCT vs. QE) did not show significant differences in effects. Moderator analysis showed larger effects when professional development was the motivation of the mentors for involvement, but not for basis of inclusion of participants (environmental vs. person basis of risk), presence of other interventions, or assessment of quality of fidelity. We also undertook the first systematic evaluation of key processes that seem to define how mentoring may aid youth (e.g. identification/modeling, teaching, emotional support, advocacy) to see if these related to effects. Based on studies we could code for the presence or absence of each as part of the program effort, analyses found stronger effects when emotional support and advocacy were emphasized. These results suggest mentoring is as effective for high‐risk youth in relation to delinquency as many other preventive and treatment approaches and that emphasis on some theorized key processes may be more valuable than others. However, the collected set of studies is less informative than expected with quite limited specification about what comprised the mentoring program and implementation features. The juxtaposition of popular interest in mentoring and empirical evidence of benefits with the limited reporting of important features of the interventions is seen highlights the importance of more careful and extensive evaluations. Including features to understand testing of selection basis, program organization and features, implementation variations, and theorized processes for effects will greatly improve understanding of this intervention. All are essential to guide effective practice of this popular and very promising approach. Abstract BACKGROUND Mentoring has drawn substantial interest from policymakers, intervention theorists, and those interested in identifying promising and useful evidence‐based approaches to interventions for criminal justice and child welfare outcomes (Grossman & Tierney, 1998; Jekliek et al., 2002). Mentoring is one of the most commonly‐used interventions to prevent, divert, and remediate youth engaged in, or thought to be at risk for, delinquent behavior, school failure, aggression, or other antisocial behavior (DuBois, Holloway, Valentine, & Cooper, 2002, DuBois, Portillo, Rhodes, Silverthorn, & Valentine, 2011). One account lists over 5000 organizations within the United States that use mentoring to promote youth wellbeing and reduce risk (MENTOR/National Mentoring Partnership, 2006). Definitions of mentoring vary, but there are common elements. For the purpose of this review, mentoring was defined by the following 4 characteristics: 1) interaction between two individuals over an extended period of time, 2) inequality of experience, knowledge, or power between the mentor and mentee (recipient), with the mentor possessing the greater share, 3) the mentee is in a position to imitate and benefit from the knowledge, skill, ability, or experience of the mentor, 4) 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. A total of 46 topic and methodologically eligible studies (out of 164 outcome reports) were identified for inclusion in the meta‐analysis on delinquency and outcomes associated to delinquency: aggression, drug use, and academic achievement. OBJECTIVES This systematic review had the following objectives: a) To statistically characterize the evidence to date on the effects of mentoring interventions (selective and indicated) for delinquency (e.g. arrest, reported delinquency), and related problems of aggression drug use, school failure. b) To attempt to clarify the variation in effects of mentoring related to program organization and delivery, study methodology, and participant characteristics. c) To help define mentoring in a more systematic fashion than has occurred to date to, in turn, help clarify how intervention processes suggested as compromising how mentoring has effects and other important considerations for future research.. d) To inform policy about the value of mentoring and the key features for utility. SEARCH STRATEGY This is an update of a review completed 4 years ago. In the original review search we benefitted from the authors of three meta‐analyses on mentoring or related topics (1) DuBois et al. (2002) on mentoring in general, 2) Lipsey and Wilson (1998) on delinquency interventions in general, and 3) Aos et al. (2004) on interventions for delinquency and associated social problems) who provided databases on reports and coding approaches. In addition, we searched various databases including PsychINFO, Criminal Justice Abstracts, Criminal Justice Periodicals Index, Social Sciences Citation Index (SSCI), Science Citation Index (SCI), Applied Social Sciences Indexes and Abstracts (ASSIA), MEDLINE, Science Direct, Sociological Abstracts, Dissertation Abstracts, Database of Abstracts of Reviews of Effectiveness, and ERIC (Education Resources Information Center) and the Social, Psychological, Educational and Criminological Trials Register (SPECTR‐ in original search), the National Research Register (NRR, research in progress), and SIGLE (System for Information on Grey Literature in Europe). Finally, the reference lists of primary studies and reviews in studies identified from the search of electronic resources were scanned for any not‐yet identified studies that were relevant to the systematic review. For this update we searched the same databases (except SPECTR as it no longer existed), surveyed pertinent journals and the reference lists of primary studies and reviews. SELECTION CRITERIA 1. Studies that focused on youth who were at risk for juvenile delinquency or who were currently involved in delinquent behavior. Risk is defined as the presence of individual or ecological characteristics that increase the probability of delinquency in later adolescence or adulthood. 2. We included interventions focusing on prevention for those at‐risk (selective interventions) and treatment (indicated interventions) that included mentoring as the intervention or one component of the intervention and at least measured impact of the program. We excluded studies in which the intervention was explicitly psychotherapeutic, behavior modification, or cognitive behavioral training and indicated provision of helping services as part of a professional role. 3. We required studies to measure at least one quantitative effect on one of the four outcomes (delinquency, aggression, substance use, academic achievement) in a comparison of mentoring to a control condition. Experimental and high quality quasi‐experimental designs were included. 4. The review was limited to studies conducted within the United States or another predominately English‐speaking country and reported in English and to studies reported between 1970 and 2011. We did not have resources for translating reports not reported in English. DATA COLLECTION AND ANALYSIS All eligible studies were coded using a protocol derived from three related prior meta‐analyses, with 20% double‐coded. The intervention effect for each outcome was standardized using well established methods to calculate an effect size with 95% confidence intervals for each of the four outcomes (if included in that study): delinquency, aggression, drug use and academic achievement. Meta‐analyses were then conducted for each independent study within a given outcome (delinquency, aggression, drug use, and academic achievement). Effect sizes for each study were scaled so that a positive effect indicated a desirable outcome (i.e., lower delinquency, drug use, and aggression or higher academic achievement). MAIN RESULTS A total of 164 studies were identified as meeting inclusion criteria as focused on delinquency and mentoring. Of these, 46 met the additional criteria for inclusion in the quantitative analyses. 27 were randomized controlled trials and 19 were quasi‐experimental studies involving non‐random assignment, but with matched comparison groups as was described above. Twenty‐five studies reported delinquency outcomes, 25 reported academic achievement outcomes, 6 reported drug use outcomes, and 7 reported aggression outcomes. Main effects sizes were positive and statistically significant for all four outcomes. Some studies showed effects that were not significant and a few reported negative effects. For each outcome there was substantial variation in effect size, too. Average effects were larger for delinquency than for other outcomes. When moderation was tested, there was considerable variation in effect sizes of studies that were similar in regard to the presence of a given moderating influence. We compared effect sizes of those studies that were random assignment experimental designs with those that were quasi‐experimental using meta‐regression and found no evidence of differences in effect sizes. We conducted moderator analyses to determine whether effects found differed by 1) criteria for selecting participants, 2) presence of other components along with the mentoring intervention, 3) motivation of mentors for participation, or 4) assessment of quality or fidelity of implementation of the intervention. We also conducted moderator analyses to test for outcome differences by the presence or absence of four theorized key components of mentoring interventions. The relatively limited information about potential moderating characteristics extractable from many reports and the limited number of reports with extractable information led us to combine effects across all four outcomes to enable adequate power and in combination to our directional expectations for moderators to test significance using a one‐tailed test (p