NSDUH collects highly-sensitive information from individual respondents, including data on substance use and mental health concerns. Ensuring respondent confidentiality is crucial to encouraging participation in the survey and responses are protected under the Confidential Information Protection and Statistical Efficiency Act (CIPSEA).
To ensure that no individual respondent can be identified from his or her responses, NSDUH public-use files (PUFs) have been treated with a number of disclosure-avoidance methods. For NSDUH, these include, but are not limited to:
- The public use data do not include any geographic identifiers, including state.
- The public use data include only collapsed age categories and do not include continuous age variables (including age at first use of substances).
- Some variables such as income have been recoded to courser levels than those found in the restricted data.
- Other demographic variables (i.e., immigrant status) have also been removed to protect the confidentiality of respondents.