Statistical analysis
’ cognitive, motivational and emotional responses
SENSITIVITY, REGRESSIONS
Data were analysed using Stata/MP V.16.1 (StataCorp, College Station, Texas). One-way analyses of variance with Bonferroni-adjusted post hoc pairwise comparisons were used to test for differences in participants’ cognitive, motivational and emotional responses to the counter-ad (measured at baseline) by condition. Overall differences in participants’ level of support for each policy proposal were assessed using McNemar’s test. Separate logistic regressions were conducted to test for differences by condition in the proportion of participants who were in support of each policy proposal, agreed with each alcohol industry belief statement and reported liking alcohol companies in general (all outcomes measured at follow-up). Where a significant (p < 0.05) omnibus test for condition was found, pairwise differences were assessed with a Bonferroni correction applied for multiple comparisons. All models controlled for days elapsed between surveys, dose of advertising exposure and game number. Sensitivity analyses were conducted using the original, continuous versions of the policy support and industry belief variables (see Supplementary Material 1). As the pattern of results was generally comparable to those found when using the dichotomous versions of these variables, for ease of interpretation, only the latter are presented in text.