National Household Survey on Drug Abuse, 1994 (ICPSR 6949)

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NHSDA 1994

This series measures the prevalence and correlates of drug use in the United States. The surveys are designed to provide quarterly, as well as annual, estimates. Information is provided on the use of illicit drugs, alcohol, and tobacco among members of United States households aged 12 and older. Questions include age at first use as well as lifetime, annual, and past-month usage for the following drug classes: marijuana, cocaine (and crack), hallucinogens, heroin, inhalants, alcohol, tobacco, anabolic steroids, nonmedical use of prescription-type psychotherapeutic drugs, and polysubstance use. Respondents were also asked about substance abuse treatment history, illegal activities, problems resulting from use of drugs, perceptions of the risks involved, and personal and family income sources and amounts. Questions on need for treatment for drug or alcohol use, criminal record, and needle-sharing were also included. A split sample design using two questionnaires was employed with the 1994 NHSDA. The 1994-A questionnaire is comparable to NHSDA questionnaires prior to 1994 and contains all of the core questions from previous NHSDAs. The 1994-B questionnaire, which includes new questions on access to care and mental health, incorporates significant changes from the previous questionnaires and can only be compared to NHSDA surveys in 1995 and beyond. The changes to the questionnaire were undertaken in order to facilitate respondent cooperation, enhance the clarity of questions, improve the accuracy of responses, and increase the reliability of measurements across survey years. In addition, a rural supplementary sample was included in 1994 to obtain substance abuse prevalence estimates for rural areas. Demographic data include gender, race, age, ethnicity, marital status, motor vehicle use, educational level, job status, income level, veteran status, and past and current household composition.

United States Department of Health and Human Services. Substance Abuse and Mental Health Services Administration. Office of Applied Studies. National Household Survey on Drug Abuse, 1994. Ann Arbor, MI: Inter-university Consortium for Political and  Social Research [distributor], 2013-06-20.

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Users are reminded by the United States Department of Health and Human Services that these data are to be used solely for statistical analysis and reporting of aggregated information and not for the investigation of specific individuals or treatment facilities.

Inter-university Consortium for Political and Social Research

Data were collected by Research Triangle Institute, Research Triangle Park, NC, and prepared for release by National Opinion Research Center, Chicago, IL.

For selected variables, statistical imputation was performed following logical imputation to replace missing responses. These variables are identified in the codebook as "...LOGICALLY IMPUTED" and "...imputed" for the logical procedure or by the designation "IMPUTATION-REVISED" in the variable label when the statistical procedure was also performed. The names of statistically imputed variables begin with the letters "IR". For each imputation-revised variable there is a corresponding imputation indicator variable that indicates whether a case's value on the variable resulted from an interview response or was imputed by the hot-deck technique, which is described in the codebook.

The "basic sampling weights" are equal to the inverse of the probabilities of selection of sample respondents. To obtain "final NHSDA weights," the basic weights were adjusted to take into account dwelling unit-level and individual-level non-response and further adjusted to ensure consistency with population projections from the United States Bureau of the Census.

To protect the confidentiality of respondents, all variables that could be used to identify individuals have been encrypted, collapsed, or deleted. These modifications should not affect analytic uses of the data.

Family and personal income range variables in the 1994-B questionnaire were constructed from two imputation-revised variables that were deleted from the public use dataset and codebook due to confidentiality issues. Users are advised that the recoded income range variables cannot be replicated from the imputation-revised variables (IRFINC1 and IRPINC1) contained in the public use file.

(a) Only the 1994-A file should be used to analyze trend data from past NHSDAs. (b) Prevalence estimates for 1994 should be derived only from the 1994-B survey, using the imputed data rather than raw data from the questionnaire or drug answer sheets. (c) Due to the split sample design, users are advised to use the imputation-revised variables for tabular summaries and other descriptive analyses for trends with NHSDA surveys prior to 1994. For analyses of relationships using multiple variables, use of non-imputed data items may be best. (d) Users who wish to replicate results published in the NHSDA Main Findings Report or other SAMHSA reports should use the 1994-A imputation-revised variables for trends only.

For some drugs that have multiple names, questions regarding the use of that drug may be asked for each distinct name. For example, even though methamphetamine, methedrine and desoxyn are the same drug, their use was measured in three separate variables.

Multistage area probability sample design involving five selection stages: (1) primary sampling units areas (e.g., counties), (2) subareas within primary areas (blocks or block groups), (3) listing units within subareas (housing units or group quarters), (4) age-group-smoking classes within sampled listing units, and (5) eligible individuals within sampled age-group-smoking classes. One hundred twenty-seven Primary Sampling Units (PSUs), including areas of high Hispanic concentration, were selected to represent the total United States population. These PSUs were defined as metropolitan areas, counties, groups of counties, and independent cities. The main sample consisted of the 117 PSUs used in the NHSDA 1993 sample. Of these 117 PSUs, 45 were selected with certainty and 72 were randomly selected with probability proportional to size. The certainty PSUs were constructed from Metropolitan Statistical Areas (MSAs) or adjoining MSAs and stratified based primarily on the concentration of Hispanics. Once a sufficient number of Hispanic dwellings was identified, the non-Hispanic Black (Black) and non-Hispanic non-Black (White/others) interviews were proportionally allocated to the strata. The rural supplement consisted of an additional ten non-MSA rural PSUs. Based on correlations between past month cigarette smoking and drug use, cigarette smokers were oversampled to increase the precision of drug use estimates. The four age groups were: ages 12 to 17, 18 to 34, 35-49, and 50 and older. The three race/ethnic groups were: Whites/others, Blacks, and Hispanics. Blacks and Hispanics were oversampled. The age-group-smoking selection probabilities were based on the desired sample sizes for each age group by racial/ethnic domain. The probabilities of selecting the person within the age-group-smoking domain were based on the number of persons found in the age-smoking group.

The civilian, noninstitutionalized population of the United States aged 12 and older, including residents of noninstitutional group quarters, such as college dormitories, group homes, civilians dwelling on military installations, and persons with no permanent address, such as homeless people and those living in shelters and rooming houses.


personal interviews and self-enumerated answer sheets (drug use)

survey data

The overall interview response rate was 76.5 percent for the 1994-A survey and 78.2 percent for the 1994-B survey. A completed interview had to contain, at a minimum, data on the recency of use of marijuana, cocaine, and alcohol. About four-fifths of respondents received the 1994-B questionnaire, and one-fifth received the 1994-A questionnaire, based on random assignment. The 1994-A interview response rates for the three racial/ethnic groups were: 75.7 percent for Whites/others, 76.7 percent for Blacks, and 78 percent for Hispanics. The 1994-B interview response rates for the three racial/ethnic groups were: 76.7 percent for Whites/others, 79 percent for Blacks, and 80.4 percent for Hispanics. The 1994-A study yielded an 85.3 percent eligibility rate for sample households and a 93.8 percent completion rate for screening eligible households. The 1994-B study yielded an 85.4 percent eligibility rate for sample households and a 93.8 percent completion rate for screening eligible households.


2018-02-15 The citation of this study may have changed due to the new version control system that has been implemented. The previous citation was:
  • United States Department of Health and Human Services. Substance Abuse and Mental Health Services Administration. Office of Applied Studies. National Household Survey on Drug Abuse, 1994. ICPSR06949-v2. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2013-06-20.

2013-06-20 Data collection instrument released.

2008-10-28 New files were added. These files included one or more of the following: Stata setup, SAS transport (CPORT), SPSS system, Stata system, SAS supplemental syntax, and Stata supplemental syntax files, and tab-delimited ASCII data file. Modified value labels and missing values for variable GQTYPE to correct previous errors. The variable CASEID was also added to the dataset.

1997-10-29 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:

  • Performed consistency checks.
  • Standardized missing values.
  • Created online analysis version with question text.
  • Checked for undocumented or out-of-range codes.

Data were weighted based on the five stages of sampling that were used. Adjustments were made to compensate for nonresponse and sampling error. Adjustments also included trimming sample weights to reduce excessive weight variation and a post-stratification to Census population estimates. The final weight variable to be used in analysis is ANALWT.


  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

  • The citation of this study may have changed due to the new version control system that has been implemented. Please see version history for more details.

This study is maintained and distributed by the National Addiction & HIV Data Archive Program (NAHDAP). NAHDAP is supported by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health (NIH).