"The community treatment parameter estimate was significant (?=?0.51, p=0.026), indicating that community-level treatment lowered the propensity to use marijuana at the last measurement occasion over and above the effect of the 'Above the Influence' campaign. There was no evidence that school-level treatment affected the marijuana use at the last measurement occasion. Neither the community-level nor the school-level treatment for the 'Be Under Your Own Influence' campaign provided evidence of an effect on the linear rate-of-change for marijuana use. In other words, while there was evidence of a significant effect of the community-based component of the 'Be Under Your Own Influence' campaign on post-test marijuana use, the strong and consistent effects of the prior campaign on both post-tests and reduced linear trajectory of marijuana use were not replicated."

Source

Slater, Michael D., et al., "Assessing Media Campaigns Linking Marijuana Non-Use with Autonomy and Aspirations: “Be Under Your Own Influence” and ONDCP’s “Above the Influence." Prev Sci. 2011 March; 12(1): 12–22. doi: 10.1007/s11121-010-0194-1
http://www.ncbi.nlm.nih.gov/p…