What to know
- Learn what restricted data are available from the National Center for Health Statistics (NCHS) surveys and data systems.
- Researchers interested in using these data must obtain approval through the NCHS Research Data Center.
About these resources
The National Center for Health Statistics (NCHS) restricts access to data that could compromise the confidentiality of survey respondents and institutions. Researchers must submit an application to the Research Data Center (RDC) to access these data.
You should review all relevant methodological information, including analytic guidelines and sample design documentation, before applying for access.
Tip
Available NCHS data
Each NCHS survey, study, and data system collects and provides different restricted data variables. Visit the individual pages linked here to learn what variables each NCHS data collection provides.
Please refer to the resources on these pages when preparing the data dictionary for your RDC proposal.
Birth data files
Mortality data files
Geographic variables
The RDC provides select geographic codes for many NCHS surveys and data systems. Learn more about the level of geographic information provided by these data collections.
Linked data
The NCHS Data Linkage Program combines two or more datasets that have some related variables to create a new dataset. Researchers can analyze the new linked dataset to understand the relationships between different variables using data collected separately. NCHS restricts access to linked datasets, which are available through the RDC.
Other restricted variables
The RDC also hosts restricted-use data from several operating divisions within the Department of Health and Human Services (HHS) and the Environmental Protection Agency (EPA).
Learn more about other restricted data provided by these data collections.