Data from the National Death Index (NDI) has been linked to several NCHS datasets, including:
Linked mortality records provide rich data for epidemiological studies and supplementary data for project using NCHS datasets.
Participants are eligible for matching if NDI records contains sufficient information to identify them. (Different combinations of social security number, last name, first initial, date of birth, and sex are needed for identification.) Observations are then matched using different combinations of social security numbers, first and last names, rough date of birth, and father’s surname. A list of potential matches are created, and, if no match exists, the respondent is presumed to still be alive. Potential matches are scored for probability of accuracy, and accuracy scores and weights are used to select the single best match. In cases where matches are unclear, data may be reviewed by hand.
Match rates and sample sizes vary by survey and survey year. All data sets have been matched to NDI records current through 2006.
Limited public-use files are available for some datasets. Data in these files has been censored or statistically masked to protect confidentiality, and includes variables for:
Restricted files are also available through the RDC and include:
All data is collected by the National Center for Health Statistics and is made available through Census RDCs under arrangement with NCHS. Interested users must submit a proposal to the RDC at NCHS for access to restricted data. Availability of data is subject to the discretion of NCHS. For up-to-date and detailed information on data, please visit the page for mortality files.