Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Improvements Are Needed To Ensure Provider Enumeration and Medicare Enrollment Data Are Accurate, Complete, and Consistent


Health care provider information, including providers' unique National Provider Identifiers (NPIs), is maintained in the National Plan and Provider Enumeration System (NPPES). To enroll in Medicare, providers must supply their NPIs and other information to CMS to be entered into the Provider Enrollment, Chain and Ownership System (PECOS). Accurate, complete, and consistent provider data in NPPES and PECOS help to ensure the integrity of all health care programs. Previous OIG work has revealed ongoing problems with CMS's oversight of provider data, sometimes resulting in improper Medicare payments to fraudulently enrolled providers.


We surveyed a random sample of individual Medicare providers to determine the accuracy of the provider information stored in NPPES and PECOS. We reviewed individual provider data in both NPPES and PECOS to determine whether these data were complete and consistent between the two databases. Additionally, we interviewed CMS staff to gather information about oversight of provider data in NPPES and PECOS.


Medicare provider data in NPPES and PECOS were often inaccurate and occasionally incomplete and were generally inconsistent between the two databases. In NPPES, provider data were inaccurate in 48 percent of records and complete for nearly all required variables but incomplete for conditionally required variables in 9 percent of records. In PECOS, provider data were inaccurate in 58 percent of records and incomplete in almost 4 percent. Additionally, provider data were inconsistent between NPPES and PECOS for 97 percent of records. Addresses, which are essential for contacting providers and identifying trends in fraud, waste, and abuse, were the source of most inaccuracies and inconsistencies. Finally, CMS did not verify most provider information in NPPES or PECOS.


Inaccurate, incomplete, and inconsistent provider data coupled with insufficient oversight place the integrity of the Medicare program at risk and present vulnerabilities in all health care programs. CMS should require Medicare Administrative Contractors to implement program integrity safeguards for Medicare provider enrollment as established in the Program Integrity Manual. Additionally, CMS should require more verification of NPPES enumeration and PECOS enrollment data. Finally, CMS should detect and correct inaccurate and incomplete provider enumeration and enrollment data for new and established records. CMS concurred with all three of our recommendations.