"Another possibility is that youth who had other protective factors in their lives would be more sympathetic to the aspirational messages, and as a result notice and remember them, producing higher self-reported campaign recognition and spurious positive predictive effects. This explanation, while it cannot be excluded, seems to pose only a modest threat to inference for several reasons. One is that those interested in using a product are more likely to attend to relevant messages, as noted above. Another reason is that evaluation of the prior 'My Anti-drug' campaign found at best neutral and often clear tendencies toward negative associations between earlier self-reported recognition measures of the campaign. It is not clear why spurious positive relationships would be found for the aspirational messages in 'Above the Influence' and not for the negative consequence, refusal skill, and normative messages found in the 'My Anti-drug' effort (Hornik et al. 2008). Even if there was something uniquely protective and compelling about the aspirational theme, this would suggest that the messages were well-targeted, but that the causal process was more complex than captured here, involving reinforcement of existing positive perceptions (Slater 2007). This would qualify but not change the basic findings of these analyses. Finally, the analyses of mediation reported above provide some support for our hypothesized causal processes.
"Therefore, despite the uncertainties associated with use of the self-report measure, ONDCP exposure predicting lower uptake and greater association of non-use with personal aspirations and autonomy seems plausible. At minimum, these results provide reason to believe that the possibly iatrogenic effects of the earlier version of the ONDCP campaign are not evident in response to the rebranded campaign. The negative findings from the evaluation of the 'My Anti-drug' campaign (Hornik et al. 2008) were also based on self-report and associational data in a panel data set."
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.