Data archives restrict access to certain data sets and variables in order to ensure confidentiality for study participants. Archives are concerned about respondent confidentiality with regard to either:

• direct identifiers: e.g., name or social security number
• indirect identifiers, items that could be used in conjunction with publicly-available information to identify individual respondents: e.g., detailed geographic information, occupation, or education

Therefore, data archives sometimes make data files available in one or more of the following categories:

• Public use data: data items which could be used to identify participants are typically removed, masked, or collapsed
• Restricted data: given that removal of sensitive variables may prevent certain kinds of analysis of the data, archives, such as ICPSR, may make a restricted version of the dataset available under strictly regulated conditions.
• Enclave data: some data is so sensitive that research must be done on-site at the archive

Many data providers will make restricted data available under a restricted data use agreement.  Applications for restricted data typically require information such as:

• the name of the principal investigator (must be a faculty member, but students may sometimes have access to data as Research Staff under the agreement)
• a data protection plan created along with departmental technology staff
• confirmation of approval of the research project by the Committee on the Use of Humans as Experimental Subjects (COUHES)
• a data use agreement signed by an MIT authority. An MIT staff member will negotiate the agreement and obtain the necessary signature from an MIT official.

Some data files contain sensitive information with an even greater likelihood of identifying individuals.  Such data can only be used in a data enclave, in which the researcher performs their data analysis on-site in an enclave and then takes away only research results.

Examples of data enclaves include:

1. Census Research Data Centers

Researchers can apply for access to unpublished data from the Census Bureau's economic and demographic programs at either:

• Boston Census Research Data Center at the National Bureau of Economic Research; or
• Michigan Census Research Data Center, (note: fees waived for MIT affiliates as members of ICPSR).

2. ICPSR Data Enclave

If you are acquiring data for your research from a private company, you may be asked to sign a nondisclosure agreement (NDA), which outlines the rights of all parties. Any such agreement should be MIT officials (such as those from the Office of the General Counsel or the Office of Sponsored Program), who will work with you to ensure that the agreement complies with MIT policies and retains for your rights for academic freedom, so that you are free to publish your results.

Request a nondisclosure agreement be signed by MIT.