A recent OIG report examined $4.7 million in improper FY 2009 Medicare payments identified by CMS’s Comprehensive Error Rate Testing contractor. According to the OIG, six types of providers accounted for 94% of these errors: inpatient hospitals, durable medical equipment suppliers, hospital outpatient departments, physicians, SNFs, and HHAs. Almost all of these errors related to insufficient documentation, miscoded claims, and medically-unnecessary services and supplies.