Data were collected by Research Triangle Institute, Research Triangle Park, NC, and prepared for release by National Opinion Research Center, Chicago, IL. The National Household Survey on Drug Abuse questionnaire and estimation methodology changed with the implementation of the 1994-B survey. Therefore, estimates produced from the 1995 survey are not comparable to those produced from the 1994-A and earlier surveys. 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. Hot-deck imputation 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 nonresponse and further adjusted to ensure consistency with intercensal 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 or collapsed in the public use file. These modifications should not affect analytic uses of the public use file. Users who wish to replicate results published in the NHSDA Main Findings Report or other SAMHSA reports should use the 1995 NHSDA imputed data for prevalence estimates rather than raw data from the questionnaire or drug answer sheets. Family and personal income range variables 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. 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 (e.g., blocks or block groups), (3) listing units within subareas, (4) age-group-smoking classes within sampled listing units, and (5) eligible individuals within sampled age-group-smoking classes. A total of 115 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. Of the 115 PSUs, 43 were selected with certainty and 72 were randomly selected with probability proportional to size. 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 12-17, 18-34, 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 study yielded an 85.0 percent eligibility rate for sample households and a 94.2 percent completion rate for screening eligible households.

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 drugs including psychotherapeutics, 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, personal and family income sources and amounts, need for treatment for drug or alcohol use, criminal record, and needle-sharing. Questions on mental health and access to care, which were introduced in the 1994-B questionnaire (see NATIONAL HOUSEHOLD SURVEY ON DRUG ABUSE, 1994 [ICPSR 6949]), were retained in this administration of the survey. 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.

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..

Response Rates: The interview response rates for the three racial/ethnic groups were: 79.6 percent for Whites/others, 80 percent for Blacks, and 83.2 percent for Hispanics. The overall unweighted interview response rate was 80.6 percent. A completed interview had to contain, at a minimum, data on the recency of use of marijuana, cocaine, and alcohol.

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 civilian, noninstitutionalized population of the United States aged 12 and older, including residents of noninstitutional group quarters, such as college dormitories, group homes, shelters, rooming houses, and civilians dwelling on military installations.

Datasets: DS1: National Household Survey on Drug Abuse, 1995

National Survey on Drug Use and Health (NSDUH) Series