Key points
- The National Center for Health Statistics (NCHS) Data Linkage Program links NCHS survey data with data from Medicaid.
- Linking NCHS data with Medicaid enrollment and claims records supports research studies on health outcomes.
- Find links to data, reports, and resources for linked Medicaid data.
Overview
The National Center for Health Statistics (NCHS) connects surveys with Medicaid enrollment and claims records. These records are collected from the Centers for Medicare & Medicaid Services (CMS) Transformed Medicaid Statistical Information System (T-MSIS).
Linking NCHS survey participants with CMS T-MSIS data creates a new resource that can support research studies on health outcomes. Studies also examine the connection between government insurance programs and health outcomes.
Medicaid enrollment and claims data for 2014-2019 are available for all successfully matched NCHS survey participants. For certain NCHS surveys, the Medicaid administrative files include data from before and/or after the survey year of interview.
- Linked Medicaid data citation list (rev. 05/12/2025)
CMS T-MSIS data
- National Health Interview Survey (NHIS): 1994–2018
- National Health and Nutrition Examination Survey (NHANES): 1999–2018
- Third National Health and Nutrition Examination Survey (NHANES III)
- National Nursing Home Survey (NNHS): 2004
Formatting differences
Linked NCHS-CMS Medicaid Analytic Extract (MAX) data from 1999–2014 are available from a previous linkage for some NCHS surveys. This previous linkage is still available for use in approved research proposals, but the formats differ.
The 1999-2014 linked Medicaid data are in the Medicaid Statistical Information System (MSIS) MAX format. The current 2014-2019 linked data are in T-MSIS data format.
Restricted-use
Restricted-use NCHS-CMS Medicaid Data can be accessed only through the NCHS Research Data Center (RDC) network for approved research projects.
Data dictionaries
- Match Status (07/11/2022)
- Demographic and Eligibility (07/11/2022)
- Inpatient (07/11/2022)
- Long-term Care (07/11/2022)
- Pharmacy (07/11/2022)
- Other Services (07/11/2022)
Variable list
Linkage methods and analytical support
- The Linkage of National Center for Health Statistics Survey Data to Centers for Medicare & Medicaid Services Transformed Medicaid Statistical Information System Claims Data (2014–2019): Matching Methodology and Analytic Considerations (09/27/2024)
- Match Rate Table for NCHS-CMS T-MSIS files
- Sample sizes for restricted-use NCHS-CMS T-MSIS files
Resources
- Chronic Conditions Warehouse (CCW) T-MSIS Analytic Files Data Dictionaries
- CCW T-MSIS Analytic Files (TAF) User Guide
- TAF Technical Documentation: Annual Demographic and Eligibility File (04/2022)
- TAF Technical Documentation: Claims Files (06/2022)
- T-MSIS Analytic Files Data Quality Atlas (CMS)
- Research Data Assistance Center (ResDAC) at the University of Minnesota