Researchers commonly use message perceptions (persuasive potential) or effects perceptions (perceived behavioral impact) in formative research to select tobacco risk messages. We sought to identify whether message perceptions or effects perceptions are more useful as proxies for the behavioral impact of tobacco risk messages. In a three-week trial, 703 U.S. adult smokers (ages ≥ 21) were randomly assigned to receive brief messages on their cigarette packs about toxic chemicals in cigarette smoke (chemical messages) or control messages about properly disposing of cigarette litter. The final follow-up survey assessed message perceptions, effects perceptions, quit intentions, and six behavioral outcomes. We conducted multiple mediation analysis in a structural equation modeling framework to test the indirect effects of messages by way of message perceptions and effects perceptions. Message perceptions did not independently mediate the impact of chemical messages on any of the outcomes (7 p-values ≥ 0.01). In contrast, effects perceptions mediated the impact of chemical messages on avoiding the messages, seeking chemical information, intentions to quit smoking, butting out a cigarette, forgoing a cigarette, and making a quit attempt (6 p-values ≤ 0.001). No mediation was present for social interactions about the message (p-value = 0.72). The effect sizes for these mediated effects were small to medium. Thus, effects perceptions, but not message perceptions, were a proxy for risk messages' impact on quit intentions and six quitting and related behaviors. These findings point to the diagnostic value of effects perceptions in formative research on tobacco risk messages.
Keywords: Effects perceptions; Formative research; Multiple mediation; Perceived message effectiveness; Structural equation modeling.