top of page
Medicaidfocus-logo

FoCUS: Facts on Care in the US

Brown_School-of-Public-Health_Primary logo

FAQs

What dimensions of Medicare Advantage (MA) do these variables capture?

The MAFoCUS dataset tracks five primary dimensions of the MA program, including:

  1. Contract and Plan Types

  2. Financial and Premium Structures

  3. Geographic Plan Reach

  4. Quality Ratings

  5. Enrollment Stability and Churn

 

Please see the MAFoCUS Data Dictionary for additional details on each included measure.

 

Where do the MAFoCUS data come from?

The variables in MAFoCUS were developed from several sources: 

  • Master Beneficiary Summary File (MBSF) includes beneficiary-level data from CMS that provides beneficiary characteristics and Part C plan and enrollment information.

  • Medicare Encounter files from CMS provide detailed records on healthcare utilization by MA enrollees. These data were used to identify enrollees with an Alzheimer’s Disease and Related Dementias (ADRD) diagnosis.

  • Residential History File (RHF) is a data resource developed at the Brown University Center for Gerontology and Healthcare Research. This dataset was used to identify enrollees with nursing facility admissions. See the LTCFoCUS FAQ for more information on RHF.

  • Publicly available CMS Medicare Advantage/Part D Contract and Enrollment files were used to develop plan and contract characteristic variables. These included files such as MA Contract Service Area by State/County Data, MA Part D Benefit Data, Special Needs Plan (SNP) Data, Dual-Eligible SNP Data, and Medicare Advantage Value-Based Insurance Design (VBID) Materials. 

  • National Bureau of Economic Research (NBER)’s MA and Cost Plans Data were used to develop plan and contract financial characteristics.

 

Please see the Data Dictionary for the data source of each variable.

​

How are the data aggregated? 

The MAFoCUS dataset includes data from years 2016 to 2023 and represents organizations operating in all 50 states, Washington, D.C, and Puerto Rico. The data are available in two separate files that provide data at the Contract or Plan level. Data in each file represent one observation per year per unit. 

 

What is the timeframe of the aggregation?

Measures are based on April of each year, considering that the MA Open Enrollment Period runs from January 1 to March 31.

​

Where can I see a full list of variables?

The Data Dictionary for each available file is provided using the same link sent to your email following your data download request. You can request the data download link on the Download the Data webpage. 

​

How is missingness defined in the dataset?

Missingness is defined in 5 ways in the dataset:

  • .A = “Absent,” which indicates that the source data for the year in question is not available. Example variables with missing values due to absent years of data include Value-Based Insurance Design variables (only years 2021 - 2023 are available) and variables summarizing Alzheimer's and related dementias prevalence (only years 2016 - 2021 are available for now due to a lag in encounter data availability). The “Year” column in the data dictionary for each file indicates the years available for each variable.

  • .L = “Low number,” which indicates that the cell count for the variable was 10 or less. A cell of 10 or less cannot be displayed per CMS’s suppression policy. Therefore, in this data, if either the numerator or the denominator was less than or equal to 10 after aggregating, the result was set to .L, along with the cell with next lowest value, as counter-suppression. 

  • .N = “Not applicable,” which indicates that the measure’s denominator is missing or set to 0. For example, if a plan is not a special needs plan (SNP), then variables indicating type of SNP (dsnp, isnp, and csnp) will be set to .N. 

  • .M = “True missing,” which indicates that the data source is available and successfully linked into the base file by ID (e.g., plan or contract ID), but the value is reported as missing in the data source.

  • .U = “Unmatched ID”, which indicates that the data source is available, but the contract or plan ID was not found in the data source.

​

How were the measures chosen? Can we request additional measures?

We compiled measures that we viewed as top priorities as of July 2026. We plan to expand the dataset to include additional measures in the future. Please feel free to contact us if you would like to submit measures for consideration in future versions of MAFoCUS!



If you have additional questions related to the data, please reach out to us at FoCUS@Brown.edu.

bottom of page