We quote what follows from a report provided at the non-partisan General Accounting Office (http://www.gao.gov/htext/d06818.html), U.S. Federal Government. The GAO was asked to evaluate the quality of the research done to evaluate the centerpiece of the campaign to reduce entry level drug use among youth in the U.S. The full report is available at this link.
"Between 1998 and 2004, Congress appropriated over $1.2 billion to the Office of National Drug Control Policy (ONDCP) for the National Youth Anti-Drug Media Campaign. The campaign aimed to prevent the initiation of or curtail the use of drugs among the nation's youth. In 2005, Westat, Inc., completed a multiyear national evaluation of the campaign.
"...GAO's review of Westat's evaluation reports and associated documentation leads to the conclusion that the evaluation provides credible evidence that the campaign was not effective in reducing youth drug use, either during the entire period of the campaign or during the period from 2002 to 2004 when the campaign was redirected and focused on marijuana use.
"...By collecting longitudinal data--i.e., multiple observations on the same persons over time--using generally accepted and appropriate sampling and analytic techniques, and establishing reliable methods for measuring campaign exposure, Westat was able to produce credible evidence to support its findings about the relationship between exposure to campaign advertisements and both drug use and intermediate outcomes. In implementing the study, Westat encountered problems that are common to large-scale longitudinal studies, and it addressed those using methods that are generally recognized as appropriate approaches for the study implementation challenges Westat faced.
"...For intermediate outcome measures thought to influence the ultimate target of the campaign, youth drug use--for example, recall and identification of campaign messages, youth anti-drug attitudes, and parents' beliefs and behaviors--Westat found favorable effects for some measures and subgroups, as well as unfavorable effects and no significant effects for others. In general, both youth and parents' recall of specific campaign messages increased over the life of the campaign. In addition, NSPY trend data showed some increasing trends in anti-drug attitudes and beliefs as well as the proportion of youth who reported never intending to try marijuana. However, cross-sectional and longitudinal analysis provided no evidence that these trends resulted from campaign exposure. Westat's analysis also indicated that among current, non-drug-using youth, exposure to the campaign had unfavorable effects on their anti-drug norms and perceptions of other youths' use of marijuana--that is, greater exposure to the campaign was associated with weaker anti-drug norms and increases in the perceptions that others use marijuana. (Emphasis supplied.) Data for parents in the NSPY on five intermediate measures show some favorable effects of campaign exposure on parents' behaviors and beliefs. However, for a major aim of the campaign, affecting parental behaviors regarding monitoring their children's whereabouts, activities, and friends, Westat found no evidence of a significant effect. (Emphasis supplied.) Moreover, where the data showed favorable relationships between campaign exposure and parental beliefs and behaviors, Westat did not find that these effects on parents ultimately lead to corresponding changes in their children's beliefs and behaviors.
"Westat's evaluation found no significant favorable effects of campaign exposure on marijuana initiation among non-drug-using youth or cessation and declining use among prior marijuana users. Westat's NSPY data did show some declining trends in self-reported lifetime and past-month use of marijuana by youth over the period from 2002 to 2004 and declining trends in youth reports of offers to use marijuana. Declining drug use trends in the NSPY were consistent with trends in other national surveys of drug use over these years. However, Westat cautioned that because trends do not account for the relationship between campaign exposure and changes in self-reported drug use, trends alone should not be taken as definitive evidence that the campaign was responsible for the declines. ONDCP has also acknowledged the limitation of drug use trends for the purpose of demonstrating a causal link between campaign exposures and declines in drug use trends. Westat's analysis of the relationship between exposure to campaign advertisements and youth self-reported drug use in the NSPY data for the entire period covered by its evaluation--assessments that used statistical methods to adjust for individual differences and control for other factors that could explain changes in self-reported drug use--showed no significant effects of exposure to the campaign on initiation of marijuana by prior nonusing youth. Westat's analysis found significant unfavorable effects--that is, a relationship between campaign exposure and higher rates of initiation--during one round of NSPY data and for the whole period of the campaign among certain subgroups of the sample (e.g., 12 1/2 to 13 year-olds and girls). Westat found no effects of campaign exposure on rates of quitting or use by prior users of marijuana.
"In light of the fact that the phase III evaluation of the media campaign yielded no evidence of a positive outcome in relation to teen drug use and congressional conferees' indications of their intentions to rely on the Westat study, Congress should consider limiting appropriations for the National Youth Anti-Drug Media Campaign beginning in the fiscal 2007 budget year until ONDCP is able to provide credible evidence of the effectiveness of exposure to the campaign on youth drug use outcomes or provide other credible options for a media campaign approach. In this regard we believe that an independent evaluation of the new campaign should be considered as a means to help inform both ONDCP and Congressional decision making."
For your information, recently there was a meeting of prior drug czars in the U.S., who reflected on the drug war. Their opinions are found in this document: 2006 Drug Czar Conference: A Reflection on Three and a Half Decades of National Drug Policy.