SEER-Medicare: How the SEER & Medicare Data are Linked
The linkage of the SEER-Medicare data is a collaborative effort of the NCI, the SEER registries, and the Centers for Medicare and Medicaid Services (CMS), formerly known as the Health Care Financing Administration. The linkage of persons in the SEER data to their Medicare claims is performed by NCI and CMS and is not the responsibility of investigators seeking to use the data.
To link SEER with Medicare data, the registries participating in the SEER program send individual identifiers for all persons in their files. These identifiers are matched with identifiers contained in Medicare's master enrollment file. The linkage was first completed in 1991 and has been updated in 1995, 1999, 2003, 2006, 2009, 2012, 2014, 2016, and 2018. For each of the linkages, 95 percent of persons age 65 and older in the SEER files were matched to the Medicare enrollment file. NCI and CMS plan to update the SEER-Medicare linkage every two years, with Medicare claims for linked cases extracted in the intervening years.
The process for matching persons appearing in the SEER data with their Medicare records is described in:
Warren JL, Klabunde CN, Schrag D, Bach PB, Riley GF. Overview of the SEER-Medicare Data: Content, Research Applications, and Generalizability to the United States Elderly Population. Med Care 2002 Aug;40(8 Suppl):3-18.