Depending on the type of provider to be reviewed and the emphasis of the evaluation, HCFA uses three distinct approaches. When statistics or other information suggest questionable practices, an aberrant cost study is conducted for institutional providers who are reimbursed on a cost basis, while ambulatory care providers who are reimbursed on a charge or fee basis are subjected to a systematic abuse review. In a program implementation review, HCFA examines specific aspects of a program to determine if monies are being spent appropriately. HCFA conducts all program validations by first reviewing information on the suspected problem, conducting an onsite assessment, evaluating these data and preparing a report, communicating these findings and recommendations to the agency, and monitoring implementation of corrective actions. HCFA reviewers are careful not to alienate providers by assuring them that selection for review does not infer misconduct but is simply a necessary administrative function. HCFA circulates summaries of reviews to Medicare contractors and State Medicaid agencies and may use their services to accomplish validation goals. Program validation supports HCFA's commitment to quality control by assessing how programs operate at the provider level and by determining if recommended improvements are made. The Office of Program Validation also administers the Secretary's authority to expel or suspend health care providers convicted of fraud or abuse from the Medicare and Medicaid programs. Program validation was still in an experimental phase in 1979, but preliminary data indicate that the goal of saving at least $4 for each dollar spent will be achieved. Examples of actual program validation reviews are cited throughout the article.