Comparing social norms for adolescent smoking and vaping behaviours using game theory based experiments and self-reports: insights from the MECHANISMS Study

Background: Many adolescent smoking prevention programs target social norms, typically evaluated with self-report, susceptible to social desirability bias. An alternative approach with limited application in public health is to use experimental norms elicitation methods.

Methods: Using the Mechanisms of Networks and Norms Influence on Smoking in Schools (MECHANISMS) study baseline data, from 12–13 year old school pupils (n=1656) in Northern Ireland and Bogotá, we compare two methods of measuring injunctive and descriptive smoking/ vaping norms. These include: (1) incentivized experiments, eliciting norms using monetary payments; (2) self-report scales. Confirmatory factor analysis (CFA) examined whether the methods measured the same construct. Paths from exposures (country, sex) to norms, and associations of norms with smoking behaviour/intentions were inspected in structural models.

Results: Second-order CFA showed latent variables representing experimental and survey norms measurements were measuring the same underlying construct of anti-smoking/vaping norms. Adding covariates into structural models showed significant paths from country to norms (second-order anti-smoking/vaping norms latent variable: standardized factor loading [β]=0.30, standard error [SE]=0.09, p < 0.001), and associations of norms with self-reported anti-smoking behaviour (β = 0.40, SE = 0.04,p < 0.001), anti-smoking intentions (β = 0.42, SE = 0.06, p < 0.001), and objectively measured smoking behaviour (β = −0.20, SE = 0.06, p = 0.001).Conclusions and implications: We provide evidence for the construct validity of behavioural economic methods of eliciting adolescents moking/vaping norms. These methods seem to index the same underlying phenomena as commonly-used self-report scales. Our research uses innovative, transdisciplinary insights from game theory about norms elicitation that will have future relevance for other health-related behaviours.