Rowan McMullen Cheng

Rowan McMullen Cheng has been the User Experience and Systems Improvement Officer at ResDAC since March 2025. She received her Master of Arts in Journalism and Mass Communication from the University of Minnesota, Bachelor of Science in Environmental Science from Iowa State University, and has over 5 years of experience in leading user experience research programs.

Master Beneficiary Summary File (MBSF) Base A/B/C/D V2

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
  • Social Security disability status variables

Special considerations

Improvements to the MBSF Base A/B/C/D file and the MBSF OTCC file!

CMS is pleased to announce the release of the enhanced Master Beneficiary Summary File (MBSF) Base A/B/C/D Version 2 (V2) file starting with the 2023 enrollment year. Additionally, the MBSF Other Chronic and Potentially Disabling Conditions (OTCC) file has also been improved.

MBSF A/B/C/D V2 File Updates

The new file includes the following enhancements:

Research Data Request & Access Policy Changes Feedback Opportunity

The Centers for Medicare & Medicaid Services (CMS) continues to evaluate our research data request and access policies, processes, and tools to ensure we are maximizing protections for controlled unclassified information (e.g., personally identifiable information and protected health information) while also enabling important research using CMS data. To further inform our next steps, CMS is seeking additional feedback from the research community. We are also releasing a summary of researcher feedback we received from CMS’ Request for Information released in February 2024.

Accountable Health Communities (AHC) Model

In 2017, the Innovation Center launched the AHC Model to assess whether identifying and addressing Medicare and Medicaid beneficiaries’ health-related social needs (HRSNs) would reduce health care use and costs. The Innovation Center funded entities called bridge organizations to convene a coalition of clinical delivery sites (CDSs) and community service providers (CSPs) to implement the AHC Model in communities across the country. Under the AHC Model, Medicare and Medicaid beneficiaries were screened by participating entities for five core HRSNs, and up to 8 supplemental HRSNs.

The AHC Research Identifiable File (RIF) contains beneficiary-level screening and navigation information about individuals participating in the AHC model. Participants included Medicare and Medicaid enrollees, 94% of whom can be linked to other CMS research files. The remaining 6% cannot be linked to Medicaid or Medicaid claims, since their Medicare and/or Medicaid ID was either missing or incomplete.

The file contains data for the entire AHC Model performance period, which began on May 1, 2017 and concluded on April 30, 2023. Screenings were conducted between May 1, 2018, and January 31, 2023, and navigation services were provided to those with at least one health-related social need (HRSN) and two or more emergency department (ED) visits between May 3, 2018, and April 30, 2023.

The file includes one record per beneficiary screening, with some beneficiaries having more than one screening. For each beneficiary, screening outcomes across domains (e.g. food, housing, safety, transportation, utilities) are reported. Some beneficiaries also have supplemental indicators related to disabilities, education, employment, family and community support, mental health, physical activity, and substance use. For screened items where a need is identified, the file contains information about services offered and their outcomes.

What does this file include? (variable highlights)

  • Person level identifiers (i.e., BENE_ID, MSIS_ID) that researchers can use to link to other CMS research files
  • Sociodemographic variables (e.g., date of birth, race and ethnicity, education, income)
  • HRSN screening results (e.g., HRSNs reported, number of ED visits in the 12 months prior to screening)
  • Navigation case information for those who were eligible and opted in to receive navigation (e.g., navigation case start and end dates)
  • Contacts between navigator and beneficiary who received navigation services (e.g., total number of successful contacts during the navigation period)
  • Navigation outcomes (e.g., beneficiary reported connection with a community service provider, beneficiary had their HRSN(s) resolved)

Special Considerations

Most beneficiaries (94%) in the file have been linked to an identifier (BENE_ID and/or MSIS_ID) that researchers can use to link to other CMS research files. For more information on how to use the data, please refer to the Accountable Health Communities (AHC) Model Data File User Guide.

EPPE Code
AHCMD

2022 and 2023 T-MSIS Medicaid and CHIP Data Now Available

CMS is pleased to announce that updated and preliminary Medicaid T-MSIS Analytic Files (TAFs) for service years 2022 and 2023, respectively, are now available. The TAF research files* contain data on Medicaid and Children's Health Insurance Program (CHIP) beneficiary demographics, program enrollment, service use, and payments. They are designed to meet the diverse research needs of the Medicaid and CHIP data user community.

Carmen Wagener

Carmen Wagener joined ResDAC in November 2024. She has a Bachelor of Science in Microbiology and Immunology from McGill University and a Master of Public Health in Environmental Health and Epidemiology from Emory University. She has previous work experience in tuberculosis transmission dynamics, foodborne disease epidemiology, and cancer clinical research.