The settings for the research were three juvenile justice correctional agencies that were using the Y-LSI for case classification in Ohio. The research sought to determine whether the Y-LSI is a valid predictor of case outcome for juvenile delinquents under correctional supervision; how juvenile correctional agencies use the Y-LSI for the allocation of correctional supervision and resources; and whether changes in the areas of risk measured by the Y-LSI through correctional treatment are associated with reductions in reoffending rates. Data were collected on youth assigned to each of the three correctional settings between July 1, 1998, and June 30, 1999. Information was collected on 1,679 juveniles. One year after the initial Y-LSI assessments, reassessment data were collected on the juveniles. Analyses were conducted for the entire sample and included calculating descriptive statistics on each group, developing a profile of offender risk and needs, and validating the instrument by using a number of outcome variables that would sufficiently answer the research questions posed. Overall, the Y-LSI was found to maintain a moderate relationship with recidivism. It was a valid predictor of risk across the three sites, maintaining the strongest relationship with recidivism measures of rearrest and technical violations. Based on these findings, this report recommends that agencies begin to use the Y-LSI to drive the delivery of services to juveniles. This involves using the individual subcomponent Y-LSI scores in addition to the overall risk score to develop offender case plans and to make treatment decisions. 35 tables, 8 figures, 46 references, and appended Y-LSI instrument, data collection instrument, and practitioner survey