Applying persuasive messages to reduce public outdoor smoking: A pseudo‐randomized controlled trial

Despite efforts to create dedicated smoking areas and no‐smoking signs, many smokers continue to light their cigarettes in front of public building entrances—leading to concerns over health consequences for non‐smokers passing by. To increase compliance with no‐smoking requests, behavioral interventions that tap into habitual and automatic processes seem promising. A pseudo‐randomized controlled trial was conducted to assess the differential impact of seven behavioral interventions based on Cialdini's principles of persuasion. Over a period of 9 weeks, the number of smokers was counted (total n = 17,930 observations) in front of a German University Medical Center. Relative to a baseline and a control condition, interventions based on the principles of reciprocity, scarcity, and authority were most effective in reducing the number of observed smokers in front of the building entrance (41.5%, 45.7%, and 52.1% reduction rates, respectively). Having observed smokers' behavior in vivo, this study provides substantial evidence for the impact of persuasive strategies on outdoor smoking. In the future, this knowledge should be used to protect non‐smokers from second‐hand smoke by increasing the use of designated smoking areas, leave to another place to smoke, or not smoke at all.