Although available without cost, NACJD data collections are not public-use data, because before using NACJD data, users agree to abide by Federal laws and scientific standards regarding human subject use. Foremost among these, users agree to analyze NACJD data solely for statistical research purposes, not to identify individuals. Therefore, all NACJD data collections have restrictions on their use. Additional restrictions are placed on some collections, where access to the collection is restricted.
Restricted access data are studies or parts of studies that NACJD does not allow users to download for confidentiality reasons. This is indicated on the download page. If only documentation or codebooks are listed, the study is restricted access data. (If downloadable data are listed, the study is restricted use data, which must be used responsibly.)
Prior to public release, the National Archive of Criminal Justice Data routinely checks all its data collections for conditions that might lead to violation of confidentiality of respondent and subject data. This is done in accord with ICPSR policy, University of Michigan policy, and U. S. Department of Justice regulations (28 CFR 22) (PDF 45K) and Federal law (42 USC 3789(g)). Blanking or otherwise modifying the values of direct or indirect identifying variables are measures sometimes taken to assure the protection of confidentiality. Occasionally, a study will require extra measures.
In such instances, the unmodified data is placed in what is referred to as the Restricted Access Data Archive. These collections or parts of collections are not publicly available through the NACJD or ICPSR Web sites.
Access to these collections is possible but only upon additional written certifications. Using a Restricted Data Use Agreement, available online as a PDF file, prospective data users must certify in writing that the data will be used for research or statistical purposes only, and that the confidentiality of respondents or subjects will be protected.
University students may gain access to the restricted data, but a faculty advisor must serve as Restricted Data Investigator. The faculty advisor and institution bear full responsibility for ensuring that all conditions of the agreement are met by the student, who must sign the Supplemental Agreement With Research Staff form. (See Forms to Request Restricted Data.)
Unaffiliated scholars, freelance consultants, employees of research organizations not affiliated with a university must make arrangements to fulfill the IRB requirement. In some cases, a coinvestigator with a university affiliation must request the data; in others, the confidentiality safeguards of the organization employing the researcher may be considered sufficient. Applicants in these situations should be particularly careful to provide full details of their plans for use of the data and for safeguarding it.
Coinvestigators from different organizations must each make a separate request for the data, complete with a data protection plan and the required signatures. Each request should refer to the fact that the researchers will be working together. The only situation in which the Supplemental Form for Research Staff is sufficient to allow multiple researchers access to the data is where there is one primary researcher who is in a position to supervise the use of the data by all others, and has the authority to discipline them for misuse.
There are two types of data collections in the restricted access archive:
Partially restricted. These studies are currently available to the public, but certain sensitive variables have been restricted. Users should first refer to the downloadable, public use version of the collection to determine if it will serve their research purposes and to find out which variables have been restricted. If the restricted variables are necessary, users can request the restricted version.
Completely restricted. In many cases, the documentation files for the studies are publicly available so users can determine if a particular study will be useful for their research.
To obtain restricted access data from either type, users must complete the forms described below.
To request data from the Project on Human Development in Chicago Neighborhoods, use the link in the Access Notes on the study home page for a particular PHDCN study to connect to the ICPSR Restricted Use Data Contract Portal. To request any other restricted data, read the instructions and download the forms packet below.
Download forms packet (PDF 132K)
A completed request can be faxed or scanned and sent as an e-mail attachment. NACJD will review the request on receipt of these forms. However, you must send us the paper hardcopy with original signatures and we must receive it before sending the data to you. Restricted access data is provided on a CD-ROM, which is mailed to the requester with a signature requirement. Please provide an address with this in mind.