days. Respondents are asked when they first used the drug. Questions are also asked about perceived risks associated with using drugs, about the actual health, social, and behavioral consequences of use, about the availability of drugs, about the setting in which the student consumes drugs, and about expected future use.
Given the sensitive nature of the questionnaire, major efforts are made to obtain valid responses and to ensure confidentiality. For 8th and 10th graders, the survey is anonymous. Seniors (12th grade) are asked to provide identifying information so that follow-up surveys can be conducted. This tracking information is administered separately from the questionnaire and kept apart from it to protect privacy. Nonetheless, the degree to which the loss of anonymity has compromised the validity of self-reports is uncertain (General Accounting Office, 1993).
Beginning with the graduating class of 1976, follow-up surveys have been administered biannually by mail to representative subsamples of respondents up to age 32, and then again at age 35 and 40. The resulting panels provide the only detailed, ongoing source of longitudinal data on drug use in the United States.2 In principle, these panel data would permit researchers to address pressing questions regarding the effects of policies on drug use and the effects of drug use on behavior, as well as basic epidemiological questions regarding duration of drug use episodes. However, citing concern for the confidentiality of respondents’ identities, the Institute for Social Research has not made the MTF longitudinal data available to external researchers.
The lack of access to the longitudinal data from Monitoring the Future has been a major concern among researchers, and the committee shares this concern. Without effective research access, the quality of the MTF data can not be assessed objectively, nor can judgments be made about whether to collect additional longitudinal data. While MTF cross-sectional data are made available in public-use format via the Inter-university Consortium for Political and Social Research (ICPSR) archive, the critical longitudinal data are not available to researchers outside the MTF team. These data are important for answering questions related to the continued pattern of drug use, which is key to policy decisions regarding the efficacy of alternative drug policies. These data in particular, and longitudinal data on drug consumption in general, may provide essential information for evaluating the efficacy of alternative drug policies. Two features about illegal drug control policy make longitudinal data uniquely important. First, illegal drug consumption and markets are complex and involve many confounding factors. Second, drugs are addictive; that is,