National Addiction & HIV Data Archive Program

Restricted-Use Data

Instructions for Access to Restricted Data

Restricted-use data are distributed when removing potentially identifying information from a dataset would significantly impair its analytic potential. NAHDAP includes restricted-use data in its holdings.

Extra steps on the part of data users are necessary to protect respondent confidentiality and ensure appropriate access to restricted-use data.

Users (and their institutions) must apply for access to restricteduse data through the ICPSR Data Access Request System using the link provided on the study's download web page. For example, researchers will see the following message and link on a study home page under Access Notes:

One or more files in this study are not available for download due to special restrictions; consult the restrictions note to learn more. You can apply online for access to the data. Authentication is required to apply for access.

The online application requires:

  • Name, department, and title of Investigator

  • Description of the proposed research that supports need to access the restricted-use data

  • Supplemental Agreement with Research Staff signed by each Research Staff member

  • Pledges of Confidentiality for each Research Staff member

  • Curriculum Vitae (CV) or resume for the Investigator and each Research Staff member

  • Requested data format (SAS, SPSS, Stata, tab-delimited ASCII or fixed-field ASCII with setups)

  • Planned data storage technology (standalone computer, external hard drive, private network)

  • Confidential data security plan (see more information below)

  • Approval or exemption for the research project from the from the Institutional Review Board of the Investigator's organization

  • A signed data use agreement (PDF example)

Applications are reviewed by NAHDAP staff for approval. If approved, the data are sent to the Investigator on an encrypted compact disk through the postal service with signature required.

Confidential Data Security Plan

The Confidential Data Security Plan is part of the signed Restricted Data Use Agreement between NAHDAP/ICPSR, the Investigator, and the Investigator's Institution. All members of the Research Staff with approved access to the restricted-use dataset are also legally obligated to follow all aspects of the Confidential Data Security Plan.

Core data security requirements:

  • Investigator agrees to ICPSR specifications on passwords and encryption.

  • Investigator satisfactorily responds to all security questions about security features to provide necessary restrictions on access to the restricted-use dataset and any derivatives.

  • Investigator satisfactorily responds to all security questions about security features to provide necessary restrictions on electronic and physical storage of the restricted-use dataset, any derivatives, temporary files, and backup files.

  • Investigator satisfactorily responds to all security questions about changes in Research Staff or Institution.

  • Investigator agrees to notify NAHDAP/ICPSR immediately if a request is made by any outside entity to access the restricted-use dataset, including requests made by funders of the research for which the restricted-use dataset are requested, as well as any legal entity or law enforcement agency.

  • Investigator satisfactorily responds to all security questions about how and when electronic and printed copies of the restricted-use data and any derivatives must be destroyed.

Access to Documentation

Documentation associated with datasets is typically available to the general public. This documentation includes the study metadata -- that is, the data describing the study -- as well as any codebooks, questionnaires, user guides, or other supporting documentation prepared for that study.

ICPSR Member-Only Data

Some data listed on the NAHDAP website are available only to persons at ICPSR member institutions. Study documentation files are still freely accessible to anyone.

Local IRB Approval to Archive Data

Institutional Review Boards (IRBs) take various approaches to secondary analysis of public- use datasets such as those distributed by NAHDAP. For more information, see ICPSR's web page on Institutional Review Boards.