The effectiveness of youth crime prevention

Evidence-based interventions are crucial for preventing that at-risk youth will develop a persistent criminal carreer. This dissertation includes a meta-analysis of the effectiveness of youth crime prevention, and an evaluation of the Dutch youth intervention ‘New Perspectives’ (NP). At-risk youth (N = 101) aged 12 to 19 years were randomly assigned to NP and care as usual (CAU). New Perspectives proved not to be more effective than other existing youth care services. However, the time to re-arrest appeared to be longer for NP-participants than for CAU-participants. Also, NP was most successful for youth with prior offenses, whereas participants without prior offenses performed better in CAU. The effectiveness of NP could be enhanced by focusing on youth with prior offenses. In addition, the findings of the meta-analysis showed small effects of crime prevention. However, under specific conditions, prevention could lead to larger positive effects; programs with behavioral contracting and training parenting skills, carried out in a family-based or multimodal format, produced the largest effects. Group-based interventions and too intensive interventions should be avoided among youth showing low risk of delinquency. Finally, this dissertation includes the results of two separate structural equation models showing that social factors, including deviant peers and low parental monitoring, mediated the association between attachment and delinquency, whereas the association between attachment and aggression was mediated by individual factors, including cognitive distortions. Clinical practice should focus on the attachment relationship between adolescent and parents in order to positively affect risk and protective factors for adolescents’ externalizing problem behavior.