Internationally, governments are making efforts to reduce rates of reoffending. Measuring progress against this objective is difficult because officially recorded reconviction rates are determined not only by how effective the justice system is in dealing with offenders but also by the characteristics of offenders coming to court. One way to measure improvements in reoffending is to develop a formula that predicts what the reconviction rate should be and then compare the predicted to the observed reconviction rate. The United Kingdom Home Office demonstrated the feasibility of this approach by developing a model to make predictions about the expected reconviction rates for adult and juvenile offenders separately. This study describes the first phase of research undertaken to construct a risk-adjustment model in Australia, similar to that developed in the United Kingdom. The technique known as the Group Risk Assessment Model (GRAM) adjusts for the characteristics of offenders coming before the courts in order to obtain more accurate estimates of trends in reoffending over time. Separate logistic regression models were developed for juvenile and adult offenders given non-custodial sanctions in 2002. An application of the models in relation to the 2003 and 2004 adult and juvenile offender cohorts revealed that there had been a statistically significant decrease in rates of reconviction among juveniles convicted in 2004 but not among adults convicted in 2004. Reconviction rates among the adult and juvenile cohorts in 2003 were not significantly different. Tables, figure, references, notes, and technical appendix