Restricted NCHS Data

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.
Research Data Center logo. Image of open and locked files.

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

After reviewing the documentation, if you cannot find the information you are looking for, please email rdca@cdc.gov.

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.

National Health and Nutrition Examination Survey
Access NHANES restricted data on genetics, dates, and geography via RDC.

National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey
Access NAMCS/NHAMCS restricted data through RDC approval; submit proposals with data dictionaries.
National Electronic Health Records Survey
Information on what restricted data are available from the National Electronic Health Records Survey
National Home and Hospice Care Survey and National Home Health Aide Survey
Access restricted data from NHHCS and NHHAS through NCHS.
National Hospital Care Survey
Explores NHCS vital data insights on hospital care patterns, policy, research, and trends.
National Hospital Discharge Survey
Find details for NHDS public and restricted variables, RDC access, and codebooks for 1977–present.
National Nursing Home Survey and National Nursing Assistant Survey
Details restricted variables in NNHS and NNAS surveys and guides on accessing them for research.
National Post-acute and Long-term Care Study
Overview of NPALS's methods and data on U.S. long-term care providers.
National Survey of Residential Care Facilities
Accessing NSRCF's restricted data via NCHS proposal submission.

National Health Interview Survey
Access NHIS variables, codebooks, and detailed data requests for 1997-2019.
NHIS-Teen
The NHIS survey that collects data about teens from teens

National Survey of Family Growth
Access NSFG restricted variables, contextual data, and geographic details for demographic research.

Restricted-Use Vital Statistics Data
National Center for Health Statistics
Data Release Policy for Vital Statistics Micro-data Files
Over the years, confidentiality standards have changed for the public release of certain details on...

Birth data files

National Maternal and Infant Health Survey
The objective of the National Maternal and Infant Health Survey (NMIHS) was to collect data needed b...

Mortality data files

Restricted-use Mortality Data Dictionary
2021 Restricted-use Mortality Data Dictionary
Download
Download
Vital Statistics: Drug Involved Mortality
Access DIM restricted use data with detailed substance and demographic insights.
Vital Statistics: Redacted Death Certificate Literal Text File
Outlines how to access redacted death certificate literal text files

NCHS Rapid Surveys System
Learn how to access National Center for Health Statistics Rapid Surveys System restricted variables

Research and Development Survey
Access RANDS survey focusing on health behaviors, conditions, and COVID-19 research.

State and Local Area Integrated Telephone Survey
Details about restricted variables in SLAITS datasets for various health surveys.

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.

Restricted-Use NCHS-VA Data
National Center for Health Statistics

Restricted-Use NCHS-HUD Data
NCHS survey data have been linked to HUD administrative data containing information on the timing of...

Restricted-Use NCHS-CMS Medicare Data
NCHS survey data have been linked to Medicare data files containing information on program enrollmen...
Restricted-Use NCHS-CMS Medicaid Data
NCHS survey data have been linked to the research-oriented Medicaid files known as the Transformed S...

2019 Restricted-Use Linked Mortality Files
NCHS survey data have been linked to the NDI data containing information on mortality status, date o...

Restricted-Use NCHS-USRDS End-Stage Renal Disease Data
NCHS survey data have been linked to End-Stage Renal Disease (ESRD) data obtained from United States...

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.

Read next

Public NCHS Data

Related Pages

NCHS Geographic Variables
Other Restricted Data
Public NCHS Data
Location of Access
Application Process
View All RDC
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About the National Center for Health Statistics
About This Page
Published: November 20, 2024
Updated: February 26, 2026

This page was last updated on this date. Updates may include minor edits, image changes, or other modifications to page content.

Reviewed: February 26, 2026

The information on this page was last reviewed by subject matter experts to ensure accuracy.