SEER-Medicare: Encrypted and Restricted Variables

Physician and Hospital Identifiers

The Center for Medicare and Medicaid Services (CMS) and the SEER registries require that the identity of physicians and other health care providers be protected. The SEER registries require that the identity of hospitals also be protected. Therefore the physician and hospital variables on the claims are encrypted. This includes the Unique Physician Identification Number (UPIN), National Provider Identifier (NPI), the provider Taxpayer ID number (tax_num), and hospital provider number (Provider Number). These numbers are encrypted in a similar manner across files and years making it possible to track the same hospital or physician over time.

Investigators who want information about hospital characteristics may request the hospital file. The hospital file includes encrypted hospital numbers making it possible to link the hospitals in the hospital file to the hospital found in Medicare claims. Investigators who wish to obtain information about physician characteristics, such as demographics, medical specialty, and board certification, can arrange for the UPINs/NPIs identified from the Medicare carrier data to be linked to data collected by the American Medical Association (AMA). This linkage is accomplished by sending the UPINs/NPIs that the researcher wishes to have linked AMA data to NCI's information technology contractor, IMS Inc. Please e-mail the UPINs/NPIs to Bob Banks at IMS will unencrypt the UPINs/NPIs and send them to the AMA's programming contractor, Medical Marketing Service, Inc. Upon completion of the linkage to the AMA data, IMS will return to the investigator a file with encrypted UPINs/NPIs and the selected AMA variables. Investigators must negotiate directly with Medical Marketing Services, Inc. about the variables needed and the cost of any processing.

Please direct any inquiries to:

Tom Lorge
Medical Marketing Services, Inc.
185 Hansen Court, Suite 110
Wood Dale, IL 60191
Phone: 630-477-1564
Fax: 630-350-1896

Geographic Identifiers

The patient's county of residence is available on the PEDSF (FIP codes) and in the Medicare files (SSA codes). To protect patient and provider identification, NCI encrypts other geographic variables including patient's census tract and ZIP code, physician ZIP code, and hospital ZIP code. Separate files that contain geographically-based (ZIP code and census tract level) socioeconomic information from the 1990 and 2000 Censuses and the 2008 – 2012 American Community Survey are provided and can be matched by the encrypted patient census tract and ZIP code.


If investigators determine that unencrypted or restricted variables are an essential part of their analysis, they must go through a special approval process. Investigators must submit their completed application form to the SEER-Medicare contact with a detailed justification for access to the restricted/unencrypted variable(s). A completed and signed request form and a list of people that will have access to these data must be included with the request. Once NCI supports the request for these variables, investigators must obtain permission from each of the registries prior to release of restricted/unencrypted variables for that registry. As of July 2014, the NCI will no longer be releasing unencrypted UPINs/ NPIs. The SEER-Medicare contact will provide investigators with contact information for the SEER registries.

Note: Files with restricted variables cannot be stored with regular SEER-Medicare data. In order to combine multiple requests when purchasing data, all requests must have the same permissions for access to any restricted variable.