Study design
non-alcoholic versus alcoholic drink
The study used a parallel-groups randomised controlled design. Individual participants were randomly allocated without stratification to one of 3 groups differing in the proportion (%) of non-alcoholic versus alcoholic drink options available for selection: Group 1: “25% non-alcoholic/75% alcoholic”; Group 2: “50% non-alcoholic/50% alcoholic”; Group 3: “75% non-alcoholic/25% alcoholic”.