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Research Data Center (RDC)

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Remote Access Process

To access data from the RDC remotely, outside researchers communicate with an automated system via e-mail. Remote access users must complete the same application process as onsite users, and after approval and registration, may utilize the remote access system. Approved projects are assigned an RDC Staff Analyst to help them manage the research.


Data confidentiality

Prior to gaining RDC Remote Access, researchers must:

  1. Complete the Application Process.
  2. Read and follow the provisions of the NCHS Manual on Confidentiality.
  3. Complete and sign the Designated Agent form Click to open pdf file 19 KB . Note: This form must be notarized.
  4. You will also need to fill out two more confidentiality forms: "Agreement Regarding Conditions of Access" Click to open pdf file 19 KB and "Researcher Affidavit of Confidentiality." Click to open pdf file 19 KB

We will sign the "NCHS Witness" lines when we receive the forms. Please mail all three forms to:

Peter Meyer, Director

Research Data Center

National Center for Health Statistics

3311 Toledo Road, Suite 4113

Hyattsville, MD 20782


Please note: The RDC reserves the right to terminate any project at any time that it deems that an investigator's actions will compromise confidentiality or ethical standards of behavior in a research environment.


Further RDC Remote Access Requirements

  • Researchers must register a credible and secure e-mail address.
  • Data requests must be in the form of SAS programs (version 9.1).
  • The SAS program must be in plain ASCII format.
  • Researchers may not write permanent datasets in the remote access disk space. Jobs that attempt to create permanent datasets or files are flagged and terminated. When this happens, an error message will be sent to the researcher.

Programming limitations with remote access

While certain limitations exist with accessing RDC data remotely, more than 50 percent of all RDC researchers access the data remotely at some point in the process. Contact your RDC Staff Analyst if the limitations prevent you from completing your research. Usually we can find alternative means for accessing the necessary data.


SAS program limits

Certain procedures and SAS functions are not allowed with remote access. For example, users cannot use PROC TABULATE or PROC IML. For a complete list of SAS limits, see the document Disallowed SAS Functions, Statements, and Procedures Click to open pdf file 19 KB . This list is periodically reviewed and may be modified as necessary.


Data limits

Cells containing fewer than five observations will be suppressed. Additional cells may be suppressed to maintain confidentiality (complementary suppression). A certain percentage of the jobs processed by the remote access system are randomly reviewed by the RDC staff for disclosure violations. If a confidentiality concern arises, the output is withheld and appropriate modifications are applied to the system to prevent such disclosures.


Other limits

  • During the first week of registration, data requests are executed in a manual mode, requiring RDC staff to review the program and resulting output before release. During this period, remote access is available only during normal working hours. After the first week, researchers may submit data requests any time and receive prompt response, except when the CDC e-mail system is down or when the remote access system is taken offline for maintenance.
  • The remote access system limits time and storage. For example, no single program can take more than one hour (clock time) to complete execution or to generate output in excess of 1.5 MB.
  • With one exception, macros are not allowed through the remote access system. The exception, GLIMIX, requires special permission.
  • Macros are not allowed through the remote access system.


Page Last Modified: December 15, 2008




National Center for Health Statistics
3311 Toledo Road
Hyattsville, MD 20782

Safer Healthier People

Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A
Tel: (404) 639-3311 / Public Inquiries: (404) 639-3534 / (800) 311-3435