SEER-Medicare: Medicare Enrollment & Claims Data (DENOM / SUMDENOM)

Denominator (DENOM) file

The Centers for Medicare & Medicaid Services (CMS)External Web Site Policy maintains a denominator file for each calendar year that includes a record for every Medicare beneficiary. For each person, the file contains his/her date of birth, date of death (if any), sex, race, state of residence, enrollment in Part A and/or Part B, and enrollment in an HMO by month. The information in the Denominator File is 'frozen' in March of the following calendar year. The Patient Entitlement and Diagnosis Summary File (PEDSF) includes enrollment information by month and year extracted from the CMS' denominator files. Therefore, a separate denominator file is not sent to investigators. Documentation for PEDSF is available on SEER Program and Data.

Summarized Denominator (SUMDENOM) file

A Summarized Denominator (SUMDENOM) file has been generated for the "non-cancer" cases. This file can be used to identify controls for cases or to develop population-based estimates of health care utilization, e.g. use of cancer tests such as PSA and mammography in the entire population. The persons in the SUMDENOM file have been identified from a random 5% sample of Medicare beneficiaries residing in the SEER areas. Some of the people in the 5% sample have cancer and will appear in the PEDSF (SEER) data. To prevent double counting, these people with cancer have been removed from the SUMDENOM file.

This file allows investigators easier access to and use of the CMS' yearly denominator data. The file includes one summary record per person with his/her date of birth, date of death (if any), sex, race, state of residence, enrollment in Part A and/or Part B, and enrollment in an HMO by month and year. In addition, there is a separate file that contains geographically-based (ZIP code level) socioeconomic information from the 1990 and 2000 Censuses and the 2008 – 2012 American Community Survey.

5% All Cancer Diagnosis File

The 5% All Cancer Diagnosis File will include all individuals that were part of the Medicare 5% sample file, but excluded from the SUMDENOM because they were reported to a SEER registry as being diagnosed with cancer. This file will include enrollment information and cancer data.

Investigators would be able to recreate a “true” 5% sample by combining the 5% All Cancer Diagnosis File and the SUMDENOM file.

The 5% All Cancer Diagnosis File may also be useful to investigators examining cancer etiology. SEER-Medicare data files can be extremely large and challenging to analyze without large computing capabilities (e.g., servers with large processing memory and storage space). Using a subset of cancers diagnosed in the SEER-Medicare 5% sample allows for more manageable analytic file sizes, particularly for questions evaluating cancer in general as an outcome.

View or download the documentation for these files: