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National Survey on Drug Use and Health Accessing Data from the National Survey on Drug Use and Health (NSDUH)
September 10, 2004

Accessing Data from the National Survey on Drug Use and Health (NSDUH)

In Brief

  • The National Survey on Drug Use and Health (NSDUH) collects data on substance use and associated topics from a representative sample of about 67,500 persons aged 12 or older each year
  • In addition to the various publications reporting NSDUH data, an extensive set of detailed data tables (over 600) associated with the national findings report is produced each year
  • To make NSDUH data files available to analysts interested in conducting their own research, SAMHSA creates public use files (PUFs) that protect NSDUH respondents' personal information from disclosure, as required by law

The National Survey on Drug Use and Health (NSDUH) is sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA) and is planned and managed by SAMHSA's Office of Applied Studies (OAS). The survey has been conducted since 1971. Prior to 2002, the name of the survey was the National Household Survey on Drug Abuse (NHSDA).

NSDUH serves as the primary source of information on the prevalence and incidence of the use of illicit drugs, alcohol, and tobacco in the civilian, noninstitutionalized population aged 12 or older in the United States. Information about substance abuse and dependence, mental health problems, and treatment for substance use and mental health problems also is included. About 67,500 interviews are conducted each year using computer-assisted interviewing (CAI) methods.


NSDUH Publications

SAMHSA produces a variety of reports containing NSDUH findings.1 National findings and descriptions of methods are published annually. Findings also are published annually for each of the 50 States and the District of Columbia. Specific highlights are discussed in short reports (usually three to four pages each) released approximately twice a month. SAMHSA also produces periodic analytic reports covering special topics of importance in greater depth than the short reports, as well as reports on methodological studies.

These and other reports can be accessed electronically at http://www.oas.samhsa.gov. To request a specific report or to be included on a mailing list to receive OAS publications, go to the OAS Mail Room at http://www.oas.samhsa.gov/maillst.htm.


Detailed Tables

An extensive set of detailed data tables (over 600) associated with the national findings report is produced each year. These tables contain prevalence estimates and estimated totals for a large variety of substance use and mental health characteristics crossed by detailed demographic and geographic categories. They include tables of standard errors (SEs) corresponding with each prevalence table, as well as p values associated with tests of statistical significance of year-to-year change. The detailed tables provide data users with information beyond what is included in the national findings report, and data users often can find the specific estimates they need without having to access data files. To facilitate searches, tables are indexed. All of the tables are available on http://www.oas.samhsa.gov at http://www.oas.samhsa.gov/webonly.htm#NSDUHtabs.


Confidentiality and Access to Data Files

Analyses presented in SAMHSA's reports and detailed tables are based on restricted analytic data files that contain the complete NSDUH dataset. These data files are available only to analysts directly involved in the NSDUH project. All of these analysts are responsible for using the data in accordance with the information provided to each respondent when he or she agreed to participate in the survey (i.e., the data will be used only for statistical purposes), and for ensuring that there is no disclosure of respondents' personal information. These responsibilities stem from legislation that outlines severe penalties for unlawful disclosure of personal information on survey respondents, as explained below.

NSDUH data are collected via face-to-face interviews with respondents. Each interview incorporates procedures to enhance the privacy and confidentiality of reported data. Names of respondents are not collected during interviews, and address information used in contacting households is kept separate from survey responses. Self-administration on a laptop computer is employed for most of the questions, preventing interviewers or other household members from observing responses. Prior to obtaining respondents' participation, interviewers explain the purpose of the study, how the data will be used, and the confidentiality protections built into the study. As part of the process for obtaining their participation, respondents are given a study description that includes information on the Confidential Information Protection and Statistical Efficiency Act (CIPSEA) of 2002. Included as Title V in the E-Government Act of 2002 (Public Law 107–347), CIPSEA provides a uniform set of confidentiality protections to all individually identifiable data collected for statistical purposes under a pledge of confidentiality. Under CIPSEA, penalties are imposed for willfully disclosing information to a person or agency not entitled to receive it; unlawful disclosure could be considered a felony with up to 5 years imprisonment and/or fines not to exceed $250,000.


Public Use Files

To make NSDUH data files available to analysts interested in conducting their own research, SAMHSA follows standard procedures used by many Federal statistical agencies, creating a public use file (PUF) that includes most of the data from the restricted dataset, but protects every NSDUH respondent's personal information from disclosure, as required by law. Preventing the possibility of disclosure of sensitive or unique information for specific individuals is accomplished in several ways. For example, detailed geographic information (e.g., State and county codes) on restricted analytic data files that, combined with other data on the file, could potentially be used to identify a respondent, is removed. Also, the link between respondents in the same household is removed to eliminate the possibility that a survey participant could identify the data for a family member who also participated in the survey.

The method developed to perform these disclosure limitation procedures in creating PUFs is called Micro Agglomeration, Substitution, Subsampling, and Calibration (MASSC).2 Variables considered to have a high potential of personal identification, as well as a high value for analysis, are treated by standard procedures of categorization and top-and-bottom coding (Agglomeration). To introduce uncertainty about the identity of any individual in a PUF, values for some variables on a sample of records are replaced with data from a different respondent who has similar characteristics (Substitution). To increase uncertainty about the presence of an individual in a PUF, a sample of records is selected and removed from the data file (Subsampling). Finally, the sampling weights are recalibrated to several estimated totals generated from the restricted data file in order to increase the precision of estimates generated from a PUF, as well as to improve their consistency with estimates from the restricted file (Calibration). It should be noted that a PUF and restricted files could potentially give different results. However, these differences are typically small.

NHSDA and NSDUH public use data files for 1979, 1982, 1985, 1988, and annually from 1990 to 2002 are currently available through the Substance Abuse and Mental Health Data Archive (SAMHDA) and the archive's online data analysis system (DAS), which allows analysts to run statistical analyses directly from a PUF and obtain results online without the need to download the data file. The PUF for each survey is generally available within 12 months of the completion of data collection. Instructions for accessing and analyzing NSDUH data online, and finding specific variables within NSDUH, are available at http://www.oas.samhsa.gov/SAMHDA.htm.


End Notes
  1. Office of Applied Studies, Substance Abuse and Mental Health Services Administration. (2003, February 7). The National Survey on Drug Use and Health (NSDUH). The NSDUH Report. [Available at http://www.oas.samhsa.gov/facts.cfm]

  2. Singh, A. C., Yu, F., & Dunteman, G. H. (2003). MASSC: A new data mask for limiting statistical information loss and disclosure [Abstract]. In Proceedings of the Joint UNECE/EUROSTAT Work Session on Statistical Data Confidentiality, Luxembourg (Working Paper No. 23). Geneva, Switzerland: United Nations Statistical Commission and Economic Commission for Europe Conference of European Statisticians, European Commission Statistical Office of the European Communities (EUROSTAT) [Available at http://www.unece.org/stats/, then http://www.unece.org/stats/documents/2003/04/confidentiality/wp.23.s.e.pdf]
The National Survey on Drug Use and Health (NSDUH) is an annual survey sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). Prior to 2002, this survey was called the National Household Survey on Drug Abuse (NHSDA). The 2003 data are based on information obtained from 67,784 respondents aged 12 or older. The survey collects data by administering questionnaires to a representative sample of the population through face-to-face interviews at their place of residence.

The NSDUH Report is prepared by the Office of Applied Studies (OAS), SAMHSA, and by RTI International in Research Triangle Park, North Carolina. (RTI International is a trade name of Research Triangle Institute.)

Information and data for this issue are based on the following publication and statistics: Office of Applied Studies. (2004). Results from the 2003 National Survey on Drug Use and Health: National findings (DHHS Publication No. SMA 04–3964, NSDUH Series H–25). Rockville, MD: Substance Abuse and Mental Health Services Administration.

Also available online: http://www.oas.samhsa.gov.

Because of improvements and modifications to the 2002 NSDUH, estimates from the 2002 and 2003 surveys should not be compared with estimates from the 2001 or earlier versions of the survey to examine changes over time.

 

The NSDUH Report (formerly The NHSDA Report) is published periodically by the Office of Applied Studies, Substance Abuse and Mental Health Services Administration (SAMHSA). All material appearing in this report is in the public domain and may be reproduced or copied without permission from SAMHSA. Additional copies of this report or other reports from the Office of Applied Studies are available on-line: http://www.oas.samhsa.gov. Citation of the source is appreciated.

This page was last updated on May 16, 2008.