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Medicare HOS Research Data Files

Several types of Medicare HOS data files are available for research purposes. Medicare HOS data files are available as public use files (PUFs), limited data sets (LDSs), and research identifiable files (RIFs). Please note that the HOS PUFs are not intended to be generalizable or used for national estimates.

HOS PUFs contain most of the survey items collected on the HOS instrument (excluding beneficiary identifying information) as well as selected additional administrative variables. HOS PUFs are constructed to prevent the identification of any single beneficiary or Medicare Advantage Organization (MAO) and only respondents to the survey are included in the files. HOS PUFs are available at no cost and can be downloaded directly from this page (see below for additional information).

Medicare HOS Public Use Data Files (PUFs)

To facilitate the dissemination of data collected by the Medicare HOS project for additional research, PUFs have been created for each cohort of data. The files have been constructed in accordance with current CMS and Department of Health and Human Services (HHS) policies and other applicable statutes and laws. All identifying information has been excluded from the files, and demographic categories (i.e., age and race) have been aggregated such that identification of any given individual is not possible.

Two distinct categories of PUFs have been generated:

1. Baseline PUFs contain the data collected during a given baseline survey administration.
2. Analytic PUFs contain the merged baseline and two-year follow up files as well as supplemental variables.

Baseline PUFs contain data for all respondents in a new cohort. Analytic PUFs contain a completed cohort of data for all baseline respondents and are constructed to be self-contained, with a baseline component and a follow up component, if available, for each beneficiary's record. There is no field that allows identification of a particular individual across the cohorts in the analytic PUFs; however, baseline PUFs have been constructed with a unique anonymous ID field that does allow identification of the same individual across multiple baseline cohorts.

Medicare HOS Limited Data Set (LDS) and Research Identifiable File (RIF)

HOS LDSs and RIFs are comprised of the entire national sample for a given cohort (including both respondents and non-respondents), and contain all the HOS survey items. The RIFs contain all the variables in the LDSs; however, the RIFs also include specific direct person identifiers and plan identifiers that are excluded or modified in the LDSs. These data files are available as SAS datasets. A signed Data Use Agreement (DUA) with CMS is required to obtain either LDS or RIF data files.

The RIFs contain direct person identifiers (i.e., name, address, Medicare Beneficiary Identifier [MBI], Medicare Health Insurance Claim [HIC] number where available, and Social Security Number [SSN] where available) that allow identification of the same individuals across multiple cohorts. Note that MBID is no longer included in RIFs beginning with Cohort 25, HIC numbers are no longer included in RIFs beginning with Cohort 22 and SSNs are no longer included in RIFs beginning with Cohort 21. The RIFs also include plan identifiers and plan characteristics for the participating MAOs, such as MAO contract number, enrollment at sampling, and plan name. The HOS LDSs retain some protected beneficiary-level health information such as date of birth, sex, race/ethnicity, and county of residence; however, specific direct person identifiers (i.e., name, address, MBI, HIC number, and SSN) are not included in the LDSs, as outlined in the Health Insurance Portability and Accountability Act (HIPAA Privacy Rule). Additionally, the MAO contract number is blinded in the LDS and certain fields describing MAOs have been modified (i.e., categorical enrollment) or excluded (i.e., plan name) to prevent identification of specific MAO contracts.

The downloadable LDS file specifications document details the characteristics of the merged baseline and follow up LDS for each available cohort of data that used the specified version(s) of the HOS (e.g., HOS 1.0, HOS 2.0, HOS 2.5, or HOS 3.0). The documentation describes the field name/description, field type, field length, additional information (including valid values), and indication of field inclusion or exclusion for the fields in each cohort file. The File Specifications document is linked below.

• Cohort 26 LDS File Specifications (PDF, 0.8 MB) includes HOS 3.0 at baseline and follow up
• Cohort 24-25 LDS File Specifications (PDF, 1.4 MB) include HOS 3.0 at baseline and follow up

HOS LDS Requests

All research requests for LDS files must be submitted through the CMS Limited Data Set File Process. Instructions are available here: Limited Data Set (LDS) Files. The Medicare HOS Information and Technical Support at hos@hsag.com remains available to answer questions about the HOS LDS files. Questions about topics such as the availability of specific data cohorts and variables should be directed to the technical support email before contacting CMS. Technical support is also available for questions about the feasibility of using the LDS files to address specific research aims.

HOS RIF Requests

Requests for HOS RIF files will continue to be processed through the Research Data Assistance Center (ResDAC), a CMS contractor that provides assistance to academic, government and non-profit researchers interested in using Medicare and/or Medicaid data. ResDAC is available to assist in the completion and/or review of data requisition forms for Medicare HOS research data files prior to their submission to CMS. For additional information and assistance obtaining Medicare HOS RIF files, please visit the ResDAC HOS page. ResDAC may also be contacted by calling 844-685-3100 between the hours of 9am to 5pm ET Monday through Friday or by emailing datarequests@cms.hhs.gov.

National Cancer Institute (NCI) SEER - MHOS Linked Data

The Surveillance, Epidemiology, and End Results (SEER) and the Medicare Health Outcomes Survey (MHOS) data resource is a data linkage available to cancer researchers. This resource links cancer registry data with patient-reported outcome measures, supporting research on the health status and health related quality of life of older adults enrolled in Medicare Advantage Organizations, including those with and without a cancer diagnosis. The current SEER-MHOS linked data resource includes HOS baseline and follow up survey data for Cohorts 1-24, collected from 1998-2023. Researchers who are interested in using the SEER-MHOS linked data will find details about the SEER-MHOS data resource and how to complete a data use application at the NCI SEER-MHOS page.

A technical report titled: “Validation of health-related quality of life scales using the VR-12 in the SEER-MHOS Data Resource” provides a validated method for scoring the Eight Scales from the VR-12 with the Eight Scales of the SF-36® for the Medicare HOS cohorts. Extensive documentation and scoring algorithms are available without any cost from Dr. Lewis Kazis at Boston University School of Public Health or the National Cancer Institute.

For access to the full technical report and SAS code to generate the algorithms, please email SEER-MHOS@hsag.com.

Additional information about the VR-12 is available from Dr. Kazis at:  

This page was last modified on 10/22/2026