Delinquent Peers and Delinquency: Findings From a Longitudinal Study of Youth.

This article investigates the dynamic, reciprocal relationship between juvenile delinquency and delinquent peer affiliation from a developmental life-course criminology (DLC) perspective, using longitudinal data from Korean adolescents. Employing group-based trajectory models (GBTMs) and cross-lagged dynamic panel data models (CLDPMs), the study identifies six distinct developmental trajectories for both delinquency and peer delinquency, revealing strong overlap and mutual influence between the two over time. Findings support interactional theory's view of continuous reciprocal effects, showing that changes in peer delinquency are significantly associated with changes in individual delinquency and vice versa, challenging theories that minimize peer influence among chronic offenders. The study highlights implications for juvenile intervention programs to address peer associations broadly across offender groups and calls for further research on offense subtypes, peer relationship continuity, measurement biases, and gender differences in peer delinquency effects.