National Household Survey on Drug Abuse, 1995 (ICPSR 6950)

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

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

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

• 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, 1995. ICPSR06950-v2. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2013-05-06. http://doi.org/10.3886/ICPSR06950.v2

2013-05-06 Data collection instrument released.

2008-10-23 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.