Polarisation of Adolescent Offending Trajectories During the Youth Crime Decline: A Multi-cohort Analysis of Justice-Involved Adolescents in Australia

Abstract Despite growing research on the youth crime decline, there has been limited analysis of how these trends have influenced offending trajectories in cohorts born after the mid-1990s. This study aimed to examine changes in offending trajectories among Australian adolescents with a proven offence aged 10–16 years across 12 consecutive birth cohorts (1995 to 2006), in Queensland, Australia. Findings indicate notable polarisation of youth offending participation and frequency trends, with a 44% decrease in the number of adolescents with a proven offence from the oldest to the youngest cohort, but significant increases in high frequency and violent offending in recent cohorts of justice-involved adolescents. Additionally, despite declines in offending participation, First Nations adolescents have become more over-represented in the youth justice system, due to steeper declines in offending participation for non-First Nations adolescents. Latent class growth analysis identified three types of offending trajectories across the birth cohorts. Multinomial logistic regression indicated that recent cohorts of justice-involved adolescents were significantly more likely to display moderate or chronic offending trajectories, compared to low-level offending. Findings suggest that while criminogenic risk has reduced across the majority of adolescents in recent birth cohorts, for a subset of adolescents it has also increased. Theoretical and policy implications are explored.