摘要：Objectives. We examined the cognitive and behavioral effects of the National Youth Anti-Drug Media Campaign on youths aged 12.5 to 18 years and report core evaluation results. Methods. From September 1999 to June 2004, 3 nationally representative cohorts of US youths aged 9 to 18 years were surveyed at home 4 times. Sample size ranged from 8117 in the first to 5126 in the fourth round (65% first-round response rate, with 86%–93% of still eligible youths interviewed subsequently). Main outcomes were self-reported lifetime, past-year, and past-30-day marijuana use and related cognitions. Results. Most analyses showed no effects from the campaign. At one round, however, more ad exposure predicted less intention to avoid marijuana use (γ = −0.07; 95% confidence interval [CI] = −0.13, −0.01) and weaker antidrug social norms (γ = −0.05; 95% CI = −0.08, −0.02) at the subsequent round. Exposure at round 3 predicted marijuana initiation at round 4 (γ = 0.11; 95% CI = 0.00, 0.22). Conclusions. Through June 2004, the campaign is unlikely to have had favorable effects on youths and may have had delayed unfavorable effects. The evaluation challenges the usefulness of the campaign. Between 1998 and 2004, the US Congress appropriated nearly $ 1 billion for the National Youth Anti-Drug Media Campaign. The campaign had 3 goals: educating and enabling America's youths to reject illegal drugs; preventing youths from initiating use of drugs, especially marijuana and inhalants; and convincing occasional drug users to stop. 1 The campaign, which evolved from advertising efforts by the Partnership for a Drug-Free America, 2 did not expect to affect heavy drug users. The campaign was designed to be comprehensive social marketing effort that aimed antidrug messages at youths aged 9 to 18 years, their parents, and other influential adults. Messages were disseminated through a wide range of media channels: television (local, cable, and network), radio, Web sites, magazines, movie theaters, and several others. Additionally, the campaign established partnerships with civic, professional, and community groups and outreach programs with the media, entertainment, and sports industries. Across its multiple media outlets, the campaign reported buying advertising from September 1999 through June 2004; it was expected that, on average, a youth would see 2.5 targeted ads per week. Sixty-four percent of the gross rating points (GRPs) purchased for the ads were on television and radio. (Within the advertising industry, GRPs are the customary units for measuring exposure to ads. If 1% of the target population sees an ad 1 time, that ad earns 1 GRP). The youth-focused ads, including ads targeted at African American youths and Hispanic youths (in Spanish), fell into 3 broad categories: (1) resistance skills and self-efficacy, to increase youths' skill and confidence in their ability to reject drug use; (2) normative education and positive alternatives, addressing the benefits of not using drugs; and (3) negative consequences of drug use, including effects on academic and athletic performance. The emphasis on each theme varied across the 5 years of the campaign studied here. To unify its advertising, beginning in 2001, the campaign incorporated a youth brand phrase: “———: My Anti-Drug” (with “Soccer,” for example, filling in the blank). Most campaign ads up to late 2002 did not concentrate on a specific drug, although some ads named marijuana. In late 2002, the campaign introduced the Marijuana Initiative, which altered the ads' mix of messages to a focus on specific potential negative consequences of marijuana use. In the final 6 months evaluated here, about half of the ads were focused on an “early intervention” initiative, that encouraged adolescents to intervene with their drug-using friends. The campaign involved many institutions. It was supervised by the White House Office of National Drug Control Policy, with overall campaign management by advertising agency Ogilvy and Mather and public relations and outreach efforts by Fleishman Hillard. Most ads were developed on a pro bono basis by individual advertising agencies working with the Partnership for a Drug-Free America. The evaluation, mandated by Congress, was supervised by the National Institute on Drug Abuse and undertaken by Westat and the Annenberg School for Communication at the University of Pennsylvania. We examine the campaign's effects on youths between September 1999 and June 2004, from its full national launch to 9 months after a major refocusing, partly in response to earlier evaluation results. 3 Effects on parents are reported separately. 4
