Peer Review Organizations (PROs) are charged by the Health Care Financing Administration (HCFA) to assist in protecting the integrity and solvency of the Medicare program. Recent audits of the Medicare program from the Office of Inspector General (OIG) revealed that more than $12 billion Medicare dollars in 1998 were spent in improper payments, with more than 25% attributed to prospective payment system (PPS) hospitals. The Payment Error Prevention Program (PEPP) is an initiative designed by HCFA in 1999 to assist PROs in meeting the goal of reducing payment errors in PPS hospitals. PEPP is implemented through the development of quality improvement (QI) methodologies. These projects are designed to achieve measurable improvements in processes and outcomes of payment errors. PEPP works to reduce payment errors at PPS hospitals through cooperative efforts with Ohio agencies and licensing boards, federal law enforcement organizations, HCFA contractors, hospital medical staffs, and medical and osteopathic associations.