"GAO's [Government Accountability Office] 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."

Source

Government Accountability Office, "ONDCP Media Campaign: Contractor's National Evaluation Did Not Find That the Youth Anti-Drug Media Campaign Was Effective in Reducing Youth Drug Use," Washington, DC: US Government Printing Office, August 2006, GAO-06-818.