One of two programs established by the Centers for Medicare and Medicaid Services (CMS) to monitor and report the accuracy of Medicare FFS payments: the Comprehensive Error Rate Testing (CERT) program and the Hospital Payment Monitoring Program (HPMP). The national error rate is calculated using a combination of data from the CERT contractor and HPMP with each component representing about 60% and 40% of the total Medicare FFS dollars paid. The CERT program measures the error rate for claims submitted to Carriers, Durable Medical Equipment Regional Carriers (DMERCs), and Fiscal Intermediaries (FIs). The HPMP measures the error rate for the quality improvement organizations (QIOs). Beginning in 2003, CMS elected to calculate a provider compliance error rate in addition to the paid claims error rate. The provider compliance error rate measures how well providers prepare Medicare FFS claims for submission. CMS calculates the Medicare Fee-For-Service error rate and estimate of improper claim payments using a methodology the OIG approved. The CERT methodology includes randomly selecting a sample of approximately 120,000 submitted claims, requesting medical records from providers who submitted the claims, and reviewing the claims and medical records for compliance with Medicare coverage, coding, and billing rules.