National Death Index
The National Death Index (NDI) is a centralized database of death record information on file in state vital statistics offices. Working with these state offices, the National Center for Health Statistics (NCHS) established the NDI as a resource to aid epidemiologists and other health and medical investigators with their mortality ascertainment activities.
- Assists investigators in determining whether persons in their studies have died and, if so, provide the names of the states in which those deaths occurred, the dates of death, and the corresponding death certificate numbers. Investigators can then make arrangements with the appropriate state offices to obtain copies of death certificates or specific statistical information such as cause of death. Cause of death codes may also be obtained using the NDI Plus service.
- Records from 1979 through 2012 are available and contain a standard set of identifying information on each death. Death records are added to the NDI file annually, approximately 12 months after the end of a particular calendar year.
- The NDI service is available to investigators solely for statistical purposes in medical and health research. The service is not accessible to organizations or the general public for legal, administrative, or genealogy purposes.
- Download the National Death Index (NDI) Application Form. Allow approximately 2 to 3 months for your application to be reviewed and approved.
- If questions arise as you are completing a DRAFT of your NDI Application Form, feel free to call NDI staff at 301–458–4444 about any section of the form.
- E-mail your unsigned NDI Application Form to firstname.lastname@example.org. This initial draft submission does not need to be accompanied by a document showing that your study has been approved by an Institutional Review Board for the Protection of Human Subjects (IRB).
- NDI staff will respond by e-mailing your assigned NDI number. Within about 1 week, NDI staff will let you know whether your draft application needs revisions before you submit your final application.
- Express mail your final, signed NDI Application Form and a current IRB approval document to the National Center for Health Statistics (see address on website). E-mail the NDI staff at email@example.com or call 301–458–4444 to confirm that we received your package or to ask questions at any time. Always include your assigned NDI number in your communication.
- Your final application will be distributed to a 12-member panel for review and comment.
- While your application is being reviewed, you can begin preparing your study subjects' records for submission on a CD. Carefully follow the specifications in Chapter 2 of the User's Guide. Note: We require that you password-protect your files using any self-decrypting software, such as PointSec, PGP, or WinZip. Call us if you need to make other arrangements for transmitting your data.
- When your application is approved, an approval package will be sent via e-mail to the Principal Investigator or Project Director appearing on the application form. The package will include a blank NDI Transmittal Form(s) and a Worksheet for Calculating NDI Charges. (Contact NDI staff if you would like to be e-mailed the worksheet in Excel format.)
- Send to NCHS, by overnight delivery, your CD containing a file(s) of study subjects' records. Include a separate NDI Transmittal Form for each file, a Worksheet for Calculating NDI Charges, and your check or purchase order. A check or purchase order must be received by NCHS before we will send you the NDI search results. Credit card payments that do not exceed $1,500 can now be accepted—contact NDI staff to arrange for such payments. (Federal agencies must process a standard NDI interagency agreement in advance of their NDI searches. Checks or purchase orders are not acceptable from federal agencies, but credit card payments of $1,500 or less can be accepted.) Once you have sent in your file(s), e-mail to NCHS your overnight-mail tracking number and the password to open your encrypted file(s) (we recommend you send it in seperate e-mails).
- Within about 2 weeks after receiving your file(s), NDI staff will return, by overnight mail, a password-protected CD containing your NDI search results, your original CD, and an NDI Repeat Request Form for future searches for the same study. NCHS staff will e-mail to you the overnight-mail tracking number and the password to open your encrypted NDI files.
- Assess your results to identify the true matches using your own assessment criteria or the suggested NDI assessment criteria. (It is your responsibility to determine which, if any, of the possible NDI matches listed is actually the correct match.) You also have the option of purchasing death certificates on your own directly from state vital statistics offices—for all true matches, or just to adjudicate selected questionable matches.
If additional NDI searches are needed later for the same study or project, first mail to NCHS a signed NDI Repeat Request Form. (You will receive a new NDI Repeat Request Form each time you receive your NDI results, but you can also access a blank Repeat Request Form on the NDI website.) You should receive a letter or e-mail approving your repeat request within 2 weeks. You can then submit your new files for your next NDI search in the same manner as the first submission.
- National Death Index User's Guide [PDF - 6 MB]
- NDI Application Form [PDF - 1.8 MB]
- Criteria to be Applied in Approving NDI Applications [PDF - 1 MB]
- NDI User Fees [PDF - 1.1 MB]
- NDI Transmittal Form [PDF - 1.1 MB]
- NDI Early Release Transmittal Form [PDF - 300 KB]
- NDI Repeat Request Form [PDF - 510 KB]
- Articles Describing the Performance of the National Death Index [PDF - 32 KB]
- Use of the National Death Index in Health Research [PDF - 241 KB]
- Citation Lists for NCHS Surveys Linked to the National Death Index [PDF - 22 KB]
How are death records matched with user records?
The NDI Retrieval Program is used to search the NDI file to determine whether a particular NDI death record qualifies as a possible record match with a particular user record. To qualify as a possible record match, both records must satisfy at least one of seven conditions or matching criteria, and the specified data items must agree on both records. See Chapter 4 of the NDI User Guide for the complete list. NDI users are encouraged to submit as many of the following data items as possible for each study subject: first and last name, middle initial, father's surname, social security number, month, day, and year of birth, race, sex, marital status, state of residence, and state of birth.
How much will the service cost?
The fees for routine NDI searches consist of a $350.00 service charge plus $0.15 per user record for each year of death searched. For example, 1,000 records searched against 10 years would cost $350 + ($0.15 x 1,000 x 10) or $1,850. Fees for the NDI Plus service are slightly higher. Refer to the NDI User Fees document for all fees and for a worksheet to assist in calculating your total charges for a NDI search.
Are discounts provided for large volumes?
If you are considering submitting more than 100,000 records for an NDI search, you may be eligible for our fee discounts for large record volumes. Contact Lillian Ingster at (301) 458-4286 for more information.
Please send us an email at firstname.lastname@example.org to submit any requests or questions you may have concerning the NDI. Please include your name, address, and phone number in your email request, and let us know if you would like to receive a free NDI information packet. You can also reach us by calling (301) 458-4444.
Contact NDI Staff:
- Division of Vital Statistics
National Center for Health Statistics
3311 Toledo Road, Room 7316
Hyattsville, MD 20782
- (301) 458-4444
- National Center for Health Statistics
3311 Toledo Rd
Hyattsville, MD 20782
- 1 (800) 232-4636
- Contact CDC–INFO