What are the effects of the Washington State Department of Labor and Industries (L&I) utilization review (UR) program on patterns of care, medical costs, and lost work time? What is the efficiency of UR as a screening tool to identify inappropriate or unnecessary medical care? The project focused on several questions: 1) What is the pattern of UR denials within and across treatment guidelines and types of procedures? 2) What factors are predictive of UR denial? 3) Did the program generate net cost savings? 4) How do these savings differ by treatment guideline, procedure or physician specialty? 5) Can the efficiency of UR be improved by using a targeted approach for case selection as opposed to the common practice of reviewing all requests for care? 6) Does UR reduce lost work time and disability by decreasing the occurrence of invasive procedures that have poor outcomes? The objective of the study was to provide policymakers with a better understanding of the efficiency, effectiveness, and clinical and economic value of UR programs.