Given the robust positive association between gangs and crime, a better understanding of factors related to reported youth gang membership is critical and especially since youth in gangs are a universal concern. The present study investigated the role of delinquency, proactive aggression, psychopathy and behavioral school engagement in reported youth gang membership using a large sample of 1027 Singapore adolescents. Results from logistic regression showed that delinquency, proactive aggression, and behavioral school engagement were statistically significant risk factors for reported youth gang membership, and that psychopathy was not related to reported gang membership. Implications for prevention and intervention work with respect to youth gang membership were discussed. In particular, strengthening students' engagement with school and meaningful school‐related activities and developing supportive teacher–student relationships are particularly important in working with young people with respect to prevention work. Additionally, the present study's theoretical and empirical contributions were also discussed.

Moffitt’s theory of delinquency suggests that at-risk youths can be divided into two groups, the adolescence- limited group and the life-course-persistent group, predetermined at a young age, and social interactions between these two groups become important during the adolescent years. We built an agent-based model based on the microscopic interactions Moffitt described: (i) a maturity gap that dictates (ii) the cost and reward of antisocial behavior, and (iii) agents imitating the antisocial behaviors of others more successful than themselves, to find indeed the two groups emerging in our simulations. Moreover, through an intervention simulation where we moved selected agents from one social network to another, we also found that the social network plays an important role in shaping the life course outcome.

Youth violence is a growing concern in Singapore. To address this complex social issue, we surveyed the psychology, social science, and criminology literature to identify a total of 11 intrinsic (familial, individual, school) complex agent is represented by a complex factor network of the 13 factors along with youth violence, coupled to each other through the extrinsic factors to form a complex social network. We simulated the model using as initial conditions the results from a large-scale school-based survey of the factors and random social ties. We¯nd factors in each complex agent evolving with time under the in°uences from other factors, and the social ties between agents evolving with time as a result of behavioral imitation between agents. We ran a sensitivity analysis on the model, to¯nd that the model is most sensitive to the parameters linking (1) non-intact family, (2) delinquency in general, (3) school disengagement, (4) peer delinquency, and (5) friends in gang to gang involvement. We also ran a series of intervention scenario simulations, and our results show that it is critical to intervene early, and successful interventions work by tipping the balance between competing intrinsic and extrinsic factors. Mental health professionals and school counsellors can then apply this unique insight from the model to design more e®ective interventions.