Data with Confidential Content

For all research projects, respondent or subject confidentiality is always a concern. Investigators are asked to review the data prior to submission to determine if the data contain information that would allow any individuals or organizations under human subjects protection to be identified.

Direct Identifiers

Most familiar are the direct identifiers that may have been collected during the course of the project. Examples of direct identifiers include:

  • Names
  • Addresses, including ZIP codes
  • Telephone numbers, including area codes
  • Social Security numbers
  • Other linkable numbers such as driver license numbers, police officer badge numbers, prisoner identification numbers, etc.

The Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule provides additional guidance regarding direct identifiers and methods for de-identification.

Indirect Identifiers

Variables that can also be problematic are the indirect identifiers that may be used in conjunction with publicly-available information to identify individual respondents. Decisions about these variables depend on the content of the data collection and the nature of the research subjects included in the dataset. Examples of indirect identifiers include:

  • Detailed geographic information (e.g., state, county, or census tract of residence)
  • Organizations (to which the respondent belongs)
  • Educational institutions (from which the respondent graduated and year of graduation)
  • Exact occupations
  • Place where respondent grew up
  • Exact dates of events (birth, death, marriage, divorce)
  • Detailed income
  • Offices or posts held by respondent

Depositing Data

All fields directly identifying the research subjects must be removed prior to deposit. Therefore, if the data contain direct identifiers and/or contact information, i.e. a roster file with names, addresses, etc., these should be not be deposited. Indirect identifiers may remain in the research data if needed to reproduce the original research findings or if removing them would significantly degrade the value of the research data.

NACJD archiving activities to process data for release include conducting a confidentiality review and using information provided by the depositor to create data files that can be released via the NACJD website and/or through one or more of the options described on our Restricted Data Details page. The Restricted Data options best balance retaining needed analytic information while providing limited and controlled access to the data. Depositors are encouraged to recommend an appropriate level of data access for the data that they deposit.

Depositors can contact NACJD staff with any questions they have about how to prepare the data with confidential content for deposit or to discuss Restricted Data or other options. NACJD staff are available by email at, or by phone at (800) 999-0960.