1.1 Summary of NHSDA Methodology

Data were collected by trained survey interviewers in selected respondents= homes. The interview took approximately one hour to complete and incorporated procedures designed to maximize truthful responses to potentially sensitive questions about illicit drug use (e.g., the use of self-administered answer sheets). Data were collected on the recency and frequency of use of various licit and illicit drugs, opinions about drugs, problems associated with drug use, and drug treatment experiences. In addition, the NHSDA collected basic demographic information on age, race/ethnicity, education, employment status, occupation, income, marital status, physical and mental health status, health service and treatment information, criminal behavior, and workplace information such as substance use policies and drug testing. Appendix B provides a detailed description of the NHSDA methodology.

This report presents rates of illicit drug use and heavy alcohol use among workers and the number of workers reporting illicit drug use and heavy alcohol use for 1994 and 1997. Tests of statistical significance were performed for comparisons of prevalence estimates between the two years. In addition, the standard errors of the rates of illicit drug use and heavy alcohol use are reported in Appendix A, which enables interested readers to perform additional hypothesis testing.