SEER-Medicaid: Medicaid Data

Medicaid is a program that is jointly funded at the federal and state level that provides health insurance for persons with limited income and/or resources that is administered by the Centers for Medicare & Medicaid Services (CMS).

Personal identifiers for all tumors diagnosed between 2006-2013, as reported to the SEER registries by November 2015, were linked to the CMS Medical Statistical Information System (MSIS) Medicaid Analytic Extract (MAX) Personal Summary (PS) Files (2006-2013*) from all 50 states and the District of Columbia using a deterministic process. Personal identifiers considered were Social Security Number (SSN), Health Insurance Claim (HIC), which is a unique Medicare number, date of birth and sex.

The resulting Medicaid Enrollment File contains one record per person-state-year combination for all persons who were found to be Medicaid enrolled during at least one month between 2006-2013. Persons can have more than one record if they were found to be enrolled in Medicaid during more than one year and/or more than one state. Note there are some persons who were found to have Medicaid enrollment in more than one state during the same year and even month.

*During the included years, states began transitioning from MSIS to the Transformed Medical Statistical Information System (TMSIS), meaning MAX-PS files were not available for all years from all states. Therefore, it is possible that some enrollment data may not have been captured. Please refer to this summary table of available MAX-PS files by state and year (XLSX, 17 KB). Depending on the research question, investigators will need to decide how to handle persons who were assessed but were never found to be enrolled in Medicaid (i.e., personal identifiers were not found in any of the Medicaid state MAX-PS files).

Last Updated: 17 Sep, 2021