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TANF "Leavers", Applicants, and Caseload Studies: Procedures for Use of the National Center for Health Statistics (NCHS) Research Data Center


  1. Functions of the NCHS Research Data Center (RDC)
  2. Cost of Using the RDC
  3. Agreements of Confidentiality
  4. Research Proposal
  5. ASPE Funds to Subsidize Access
  6. User Supplied Data
  7. Contact for Additional Information


I. Functions of the NCHS Research Data Center (RDC)

The NCHS RDC is a physical space located within the NCHS facilities in Hyattsville, Maryland where researchers are allowed access to NCHS restricted data files not released to the public. The NCHS RDC also allows access to restricted data files sponsored by the Office of the Assistant Secretary for Planning and Evaluation (ASPE). These data files do not contain direct identifiers such as name or social security number, but may contain identifiers for small geographic units such as block or census tract or may contain data from exogenous files provided by the prospective researcher. Researchers with approved projects may be granted access to these files and must complete their work within the confines of the RDC. No electronic or hard copies of data files or documents may leave the RDC without being submitted to disclosure limitation review. Researchers may only work at the RDC under the supervision of NCHS-RDC staff during normal working hours.

Prospective NCHS RDC researchers should contact the RDC staff well in advance of their planned tenure to ensure that their research proposal is accepted and all necessary data files, computer hardware and software is in place at the time of their arrival.

Use of the RDC is on a first-come, first-served basis due to limited space and resources.

Prospective users of the NCHS RDC must submit a research proposal prior to their tenure in the RDC. See below for specifics of the research proposal.

It is suggested that all prospective RDC users make a trip to the RDC early in the application process to become familiar with the facilities and RDC staff.


II. Cost of using the RDC

Researchers using the NCHS RDC will be charged for space and equipment rental and staff time necessary for supervision, disclosure limitation review, maintenance of computer facilities (including both hardware and software) and the creation and maintenance of data files required by the researcher. The cost per project is given in the table below:


Type of Access Project Cost
  All $1,000 per week
Remote access:
  NSFG-CDF $500 per year
  NHIS-Polio $500 per year
  ASPE-Welfare Outcomes $500 per month*
  ASPE-NEWWS $500 per month*
  Other files $500 per month for files with
    $1,000 per month for files with >130,000 records
* Note: Files with more than 500,000 records are generally not available through the remote access system.
* Note: Funds are available to subsidize access to ASPE-sponsored files. See section on ASPE Funds below.

The charges for onsite and remote access researchers include equipment, workspace and NCHS staff time for monitoring, providing technical assistance, disclosure limitation review, and file management.

There are additional setup charges of $500 per day of effort for files requiring special handling such as the merging of additional data or creating custom file formats.


III. Agreements of Confidentiality

In addition to the research proposal, all applicants for NCHS files will be required to sign the Agreement Regarding Conditions of Access to Confidential Data in the Research Data Center of the National Center for Health Statistics and the Researcher Affidavit of Confidentiality. Applicants for use of ASPE files will be required to sign an Agreement Regarding Conditions of Access to Confidential ASPE Data in the Research Data Center of the National Center for Health Statistics (please see the HTML version or the PDF version) and a Researcher Affidavit of Confidentiality for ASPE Data (please see the HTML version or the PDF version).

IV. Research Proposal

Prior to being granted access to confidential data files through the NCHS Research Data Center (RDC), applicants must submit a structured research proposal containing the following information:

  1. Cover letter.
  2. Project title.
  3. Abstract
  4. Full personal identification and institutional affiliation. If a student, a letter from the department chair or advisor stating that the applicant is a student working under the direction of the department.
  5. Current resume or curriculum vitae.
  6. Dates of proposed tenure at the RDC (or use of the remote access system).
  7. Source of funding.
  8. A detailed summary of the proposed research including a description of why publicly available data are insufficient.
  9. A complete list of the NCHS or ASPE data requested — data system, files, years, variables, etc.
  10. Details concerning the user supplied data, if any, to be merged with the NCHS data. This includes documentation, file layout, number of records, and restriction on NCHS using the data (currently the RDC policy is that user-supplied data is not released to anyone other than the prospective researcher).
  11. Software requirements. Currently SAS for Windows, Stata, and Watcom Fortran are available in the NCHS RDC. Other languages can be made available with sufficient lead time.

Portions of doctoral proposals or grant applications with appropriate modifications may suffice for the research proposal. It is expected that users will develop their research proposal in conjunction with RDC staff.

The completed proposal should be sent to the NCHS RDC contact listed at the end of this document.

Upon receipt of the Research Proposal, a review committee will be convened to evaluate the proposal. The Proposal Review Committee consists of the director of the NCHS RDC, the NCHS Confidentiality Officer, and the director (or designee) of the NCHS data division whose data is included in the proposal. In the case of ASPE-sponsored files, the review committee will include a member of ASPE and may include a representative from ACF in the case of the NEWWS data. The review committee will include a member of ASPE and may include a representative from the state(s) whose data are included in the proposal in the case of the leavers data sets.

The Proposal Review Committee evaluates proposals using the following criteria:

  1. Scientific and technical feasibility of the project;
  2. Availability of resources at the RDC;
  3. Risk of disclosure of restricted information; and
  4. Whether the proposed project is in accordance with the mission of the NCHS " provide statistical information that will guide actions and policies to improve the health of the American people."

For ASPE-sponsored files, the proposal will also be evaluated on how well it meets the mission of the Human Services Policy Office of ASPE, to conduct analysis, research and evaluation relating to low-income children, youth, and families, including income assistance, income security, welfare-to-work, training, and support services programs and systems.

Users should note that approval of their application does not constitute endorsement by NCHS of the substantive, methodological, theoretical, or policy relevance or merit of the proposed research. NCHS approval only constitutes a judgement that this research, as described in the application, is not an illegal use of the requested data file.


V. ASPE Funds to Subsidize Access

The Office of the Assistant Secretary for Planning and Evaluation has funds available to subsidize the costs of accessing the ASPE data sets available at the RDC. This funding can be used to waive up to 75 percent of the RDC fees, up to a total subsidy of $2,000 per research project. To apply for this waiver of fees, the applicant should attach a subsidy request as Section L. of the Research Proposal. The request should state:

  • Total estimated RDC fees for accessing ASPE data sets.
  • Requested amount of subsidy from ASPE funds (in the form of fee waiver), limited to the lower of 75 percent of total fees or $2,000. Depending on demand and ASPE priorities, ASPE may provide some, all, or none of the requested fee waiver for each project.


VI. User Supplied Data

The NCHS RDC allows users to supply their own data to be merged with NCHS data sets. The user-supplied data may consist of proprietary data collected and 'owned' by the user or other publicly available data obtained by the user such as census data. Users must provide NCHS-RDC staff with complete documentation of any data proposed to be merged with NCHS data. Users expecting to use merged files are responsible for interacting with RDC staff to ensure that their data can be merged with the NCHS data and the format of the data is consistent with the NCHS data. The NCHS RDC will not accept user data files in any proprietary format such as SAS or Stata, use files must be in ASCII format (flat files) with variables either column delimited or column specific. The merging of user-supplied data with NCHS data sets will be done by NCHS RDC staff prior to the arrival of the user. Files and information used in linking the internal and external files will be destroyed after the merge and will not be made available to the users.

The NCHS RDC, as a policy, will not release or give access to any user-supplied files to anyone without the written consent of the user who supplied the files.

The NCHS RDC periodically creates and maintains backup copies of all computer files. The backup tapes are stored in a secure storage area accessible by NCHS RDC staff only. These backup files will contain user-supplied data as well as the merged files. These backup files will only be destroyed upon the written request of the user.


VII. Contact for Additional Information

See the RDC web page at

For additional information and application form, contact:

Kenneth W. Harris
Research Data Center
6525 Belcrest Road, Suite 700
Hyattsville, Maryland 20782-2003
Voice Mail: (301) 458-4277
Fax: (301) 458-4039