The choice of message and messenger to drive behavior change that averts the health impacts of wildfires: an online randomized controlled experiment

BACKGROUND: To reduce the negative health effects from wildfire smoke exposure, effective risk and health communication strategies are vital. We estimated the behavioral effects from changes in message framing and messenger in public health messages about wildfire smoke on Facebook. METHODS: During September and October 2021, we conducted a preregistered online randomized controlled experiment in Facebook. Adult Facebook users (n = 1,838,100), living in nine wildfire-prone Western U.S. states, were randomly assigned to see one of two ad versions (narrative frame vs. informational frame) from one of two messengers (government vs. academic). We estimated the effects of narrative framing, the messenger, and their interactions on ad click-through rates, a measure of recipient information-seeking behavior. RESULTS: Narrative frame increased click-through rates by 25.3% (95% CI = 22.2, 28.4%), with larger estimated effects among males, recipients in areas with less frequent exposure to heavy wildfire smoke, and in areas where predominant political party affiliation of registered voters was Republican (although not statistically different from predominantly-Democrat areas). The estimated effect from an academic messenger compared to a government messenger was small and statistically nonsignificant (2.2%; 95% CI = − 0.3, 4.7%). The estimated interaction effect between the narrative framing and the academic messenger was also small and statistically nonsignificant (3.9%; 95% CI = − 1.1, 9.1%). CONCLUSIONS: Traditional public service announcements rely heavily on communicating facts (informational framing). Shifting from a fact-focused, informational framing to a story-focused, narrative framing could lead to more effective health communication in areas at risk of wildfires and in public health contexts more broadly. TRIAL REGISTRATION: Date registered: August 19, 2021; Registration DOI: 10.17605/OSF.IO/JMWUF SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-022-14801-6.