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NCHS Data Release and Access Policy for Micro-data and Compressed Vital Statistics Files

This document outlines NCHS/Division of Vital Statistics (DVS) policy on the release of and access to vital statistics micro-data for births, deaths, fetal deaths, linked birth/infant death, and matched multiple births. Given changes in state laws and policies on confidentiality with respect to the re-release of vital registration data, NCHS has revised its micro-data release and access policy to comply with state requirements effective with the 2005 data year.* The DVS revised policy as outlined here is consistent with CDC and NCHS goals to make data available as widely as possible while protecting respondent confidentiality, assuring data quality, and conforming to state laws and regulations on re-release of vital statistics data.

Data available to the public:

A. Public-use micro-data file content:

The release of public-use data generally coincides with the publication, or follows soon after, of DVS final annual reports on births, deaths, fetal deaths, and linked birth/infant death. DVS also publishes preliminary reports, but these are based on incomplete data, do not constitute a final data file, and are not released as micro-data. Final report publication dates vary from year to year following receipt and processing of complete data from the states and other registration areas.

Over the years, confidentiality standards have changed for the public release of geographic and date details on vital statistics micro-data files. These changes are reflected in the data available in successive time periods, as follows:

  1. Birth, death, and fetal death public-use micro-data files prior to 1989 contain all counties and exact dates (year, month, and day) of death.
  2. Birth, death and fetal death public-use micro-data files for data years 1989 to 2004 contain only geographic identifiers of counties and cities with a population of 100,000 or greater, and no exact dates. For birth, death, and fetal death files, year, month, and day of week (e.g. Monday) are available.
  3. Linked birth/infant death public-use micro-data files prior to 2005 contain geographic identifiers only for counties and cities with 250,000 or greater population and no exact dates. Year, month and day of week (e.g. Monday) of birth/death are available.
  4. Birth, death, fetal death and linked birth/infant death public-use micro-data files beginning with the 2005 data year will contain individual-level vital event data at the national level only, that is, with no geographic identifiers (no State, county, or city identifiers). These files for births, deaths, fetal deaths and linked birth/infant death will generally include most other items and detail from the vital record with the exception of exact dates. Year,month and day of week (e.g. Monday) are included. Items may vary from year to year.
  5. The Matched Multiple Birth file combines data from the six years 1995 to 2000 but excludes all geographic identifiers and exact dates of births and deaths. The file also excludes year, month and day of week (e.g. Monday). A description of the file is viewable. The Matched Multiple Birth file for 1995-2000 and an earlier version for 1995-98 are available for downloading.

Availability: Public use Birth, Period Linked Birth - Infant Death, Birth Cohort Linked Birth - Infant Death, Mortality Multiple Cause, and Fetal Death micro-data files can be downloaded from the NCHS website.

In exceptional cases involving critical issues related to public health surveillance, the DVS Director may provide data not yet publicly released to certain federal agencies following submission of a request in writing to the Director, DVS.

B. Construct your own tabulations:

Data users may also access data using internet programs to construct their own tabulations of births and deaths with geographic detail subject to population and/or cell size limitations. Some of these interactive systems allow users to build tables based on micro-data; however, only tabulated data are presented to the user. Interactive web-based systems currently available are WONDER (Wide-ranging ON-line Data for Epidemiological Research) and WISQARS (Web-based Injury Statistics Query and Reporting System).

Customized files available under restricted conditions:

A. All-counties identified:

Following the process outlined below, researchers may request customized micro-data files (birth, death, fetal death, and linked birth/infant death) and compressed files (death only) containing geographic detail for all States and counties for those data years with limited (1989-2004) or no (2005 forward) geographic detail in the public-use files.* Data for approved projects will be provided on CD or DVD at no cost. Our current agreement with the states on the re-release of restricted data requires a review of all such data requests by the National Association for Public Health Statistics and Information Systems (NAPHSIS) which represents state vital registrars. The review by NAPHSIS is conducted prior to the NCHS review and includes both federal and non-federal requests for restricted data files.
The review process is as follows:

  1. The researcher submits a completed project review form, available from NAPHSIS, to the NAPHSIS review team. Some states have laws, regulations or policies that prohibit release of certain data items. In the course of the review, the NAPHSIS review team will determine whether the request contravenes any of these state limitations. The researcher will be notified by NAPHSIS of their decision on the data request. NCHS will also be apprised of the NAPHSIS review decision, at which time NCHS will conduct its usual review.
  2. If the project proposal is approved, NCHS will send the researcher (and his/her contractors if federal) a Data Use Agreement. All data users associated with the research must agree to the conditions of usage, including the following:
    1. Researcher and associates will use a data file only for the purpose stated in the proposed scope of work;
    2. The researcher will return the micro-data or compressed files to NCHS or destroy the data files after the approved project period unless renewal is requested and approved.
    3. The data files cannot be shared with any other staff not listed in the data use agreement.
    4. The data files cannot be accessed directly or remotely outside the United States by any staff listed in the data use agreement.
    5. Researcher and associates will not attempt to link nor permit others to attempt to link the data set with individually identifiable records from any other NCHS or non-NCHS data set.
    6. Researcher and associates will not attempt to use the data sets nor permit others to use them to learn the identity of any person or establishment included in any data set.
  3. If the project proposal is denied because of the issues related to data confidentiality, alternative access may be available through the NCHS Research Data Center (RDC) which has specific procedures to follow for controlled access to micro-data files. Use of the RDC entails costs to the data requestor. See the NCHS RDC website for specific procedures.

B. Exact dates of vital events:

Researchers in federal agencies, as well as their on-site or off-site contractors can submit project proposals that request exact dates of vital events. If needed, the file with exact date can also include geographic detail. These proposals must be approved by NAPHSIS and NCHS, following the process as described above.

Non-federal researchers (including federal grantees) can gain controlled access to exact dates of vital event files only through the NCHS Research Data Center after NCHS approval.

C. The Matched Multiple Birth file:

The Matched Multiple Birth file with all States and counties or exact dates included is accessible only through the NCHS Research Data Center. See the NCHS RDC website for specific procedures.

* Micro-data refers to records for individual cases. Files released by DVS may include a single record for each birth or death, or the file may be "compressed," replacing identical records with a single record and the number of times that record occurs in the file. A compressed file reduces the number of records in the file. Compressed mortality files produced by NCHS list year and county of death, race (white, black, other), cause of death, and sex, use broad age groupings, and therefore do not contain as much detail as single record micro-data files.