Results indicated that the LSI-R was a valid and robust predictor of subsequent incarceration for the sample of Federal probationers. The validity of the LSI-R remained after controlling for the effects of offender age, sex, and ethnicity. The findings suggest that the LSI-R can be used effectively to inform correctional decisions regarding the supervision and service provision for Federal probationers. Multivariate analyses were used to examine the LSI-R scores in light of official recidivism data (subsequent incarceration in a Federal facility). Faltering budgets and increasing numbers of incarcerated offenders have strained the Federal probation and pretrial services and have required corrections staff to do more with less. Actuarial classification systems that provide valid and reliable measures of offender recidivism risk and criminogenic needs are presented as an efficient way for corrections agencies to prioritize staff workloads and budgetary resources. Classification systems place correctional populations into subgroups of similar types of offenders with similar risks and needs. While most corrections agencies use some type of classification system, all systems are not alike and are differentiated on the basis of how predictions of risk are reached (actuarial assessment versus clinical judgment) as well as the focus of the assessment. The Level of Service Inventory-Revised (LSI-R) is described as an example of an actuarial classification system that measures 54 risk and criminogenic need factors within 10 criminogenic categories, including criminal history, education/employment, family/marital relationships, and alcohol or drug use. Participants were a sample of 2,107 adult Federal probationers who were assessed using the LSI-R over a 2-year period between December 2001 and December 2003. Limitations of the study are discussed and future research is recommended on the relationship between the LSI-R and outcomes across offender sex, ethnicity, and race. Tables, references