The MBSF base segment includes beneficiary enrollment information, (A/B/C/D). Medicare Advantage (Part C) and the Prescription Drug Program (Part D) plan enrollment information is included.
What does this file include? (variable highlights)
- State, county annual SSA codes
- State, county monthly FIPS codes
- Zip code, State and County
- Date of birth, date of death
- Race
- Reason for entitlement
- Monthly enrollment for each part of the Medicare program, A/B/C/D
- Dual eligible status
- Part C plan and enrollment information
- Part D plan and enrollment information
- Part D low income cost sharing
Special considerations
- An enhanced version of this file (MBSF Base A/B/C/D V2) is available starting with the 2023 enrollment year. When requesting 2023 data, researchers will receive both the current MBSF Base A/B/C/D and the new V2 files. The current MBSF Base A/B/C/D file will no longer be produced starting with annual 2024 data. For more detailed information about the MBSF data and enhancements, reference the CCW Medicare Administrative Data User Guide and Codebook.
- Four additional segments are available for order with this file:
- Part C and Part D enrollment information are available beginning with the 2006 file year. Years prior to 2006 include an indicator variable for managed care enrollment.
