Since traditional outcome evaluations are costly and usually assess only one program at a time, Iowa's Department of Management uses performance audits in evaluating agency operations and program effectiveness. These audits are intended to help agencies demonstrate key results and also provide information that can improve program operations, facilitate decisionmaking, and contribute to public accountability. Performance audits assess the performance of a group of interventions rather than just one program. The focus of Iowa's performance audits has been the development of a methodology for performance measurement that will assess outcomes of the Department of Corrections' licensed institutional substance abuse programs. The intent of the audit is to provide an overall view of substance abuse treatment delivery within the prison system, so as to ensure fair comparisons among programs. The strength of this approach is its examination of a set of interventions designed to achieve the same outcomes. This yields data on system performance and the comparative performance of individual programs. At a minimum, this approach requires a dataset that is sufficiently large to support disaggregating data to the program/intervention level, so a comprehensive profile of outcome performance can be developed. The methodology holds the most promise when it is used as an initial screen to complement a more indepth analysis that examines causes. 1 figure and 5 notes