The National Death Index

Purpose

The National Death Index (NDI) is a resource to help researchers find out if participants in their studies have died. NDI also can help researchers learn selected mortality information for study participants' deaths.

NDI does this by providing the public health and medical research community a single source for obtaining selected mortality data for approved uses.

The National Center for Health Statistics (NCHS) worked with states to establish the National Death Index. When using NDI, researchers don't need to work through multiple jurisdictions to access selected mortality data for their study participants.

Mortality data for researchers

NDI services are available only to researchers for statistical purposes in public health and medical studies. NDI is not available for use by organizations or the general public for any non-statistical purposes, including personal losses, legal, administrative, or genealogical purposes.

NDI has helped to determine whether participants in thousands of studies have died. Researchers have used NDI data to study—

• Survival time among people with health conditions like cancer and heart disease
• Mortality risk among certain occupations like radiologists, pesticide applicators, and auto workers
• Life expectancy after surgeries from procedures like gastric bypass and bone marrow transplant
• Impact of dietary factors—like drinking alcohol or coffee, taking vitamins, coffee, and consuming dietary fats—on risk of death
• Relationships between healthcare and mortality, like the effects of types of health care on survival times
• Mortality among groups whose conditions or circumstances increase the risk of poor health outcomes, like children and adolescents with developmental disabilities, people released from prison, and people living in poverty

Available data

NDI provides selected mortality data from death certificates. States and territories submit death certificate data to NCHS through the Vital Statistics Cooperative Program.

NDI is the most complete source of death information in the United States with more than 115 million death records. It includes—

• Death records from 1979‒current for the 50 states, the District of Columbia, New York City, Puerto Rico, and the U.S. Virgin Islands
• Records from select years for Guam, American Samoa, and the Northern Mariana Islands
• Out-of-country deaths of U.S. military personnel (since 1979)
• Belated records submitted after that year's data file has closed (when available)

Once NDI makes these data available, researchers can use them to determine if any of their study participants have died. If a participant has died, NDI can provide additional information—

• State where the death occurred
• Date of death
• Death certificate number
• Cause or causes of death, if using the NDI Plus service

Data releases

The final NDI file for a calendar year becomes available 12 or more months after the end of that year. Before this can happen, NCHS must receive, process, and edit all death records from all jurisdictions.

The NDI Early Release Program makes a specific year's records available within 1 week or more from the end of that calendar year. NDI Early Release data are changed from preliminary to final within 12 months or more from the end of that year.

Latest releases

• The NDI Final File for 2022 is now available for searching.
• The NDI Early Release File for 2023 is now available for searching.
  • See completion percentages by state and territory.

Cost of searches

NDI search fees consist of a base service charge, plus an additional fee per user record. Base service charges are higher for the NDI Plus service. The additional fee per user record varies by the type of search requested.

NDI is fully funded through user fees; it receives no appropriated funds. User fees have covered all NDI operating expenses since the service was launched. Jurisdictions also receive a portion of the NDI user fees.

Contacts

Resources

Bibliographies of NDI-related articles

• Articles Describing the Performance of the National Death Index
• Use of the National Death Index in Health Research
  

Related information

• National Vital Statistics System – Mortality Data
• NCHS surveys linked to the National Death Index