Equivalent gambling warning labels are perceived differently

Background and Aims The same information may be perceived differently, depending on how it is described. The risk information given on many gambling warning labels tends to accentuate what a gambler might expect to win, e.g. ‘This game has an average percentage payout of 90%’ (return-to-player), rather than what a gambler might expect to lose, e.g. ‘This game keeps 10% of all money bet on average’ (house-edge). We compared gamblers’ perceived chances of winning and levels of warning label understanding under factually equivalent return-to-player and house-edge formats. Design Online surveys: experiment 1 was designed to test how gamblers’ perceived chances of winning would vary under equivalent warning labels, and experiment 2 explored how often equivalent warning labels were correctly understood by gamblers. Setting United Kingdom. Participants UK nationals, aged 18 years and over and with experience of virtual on-line gambling games, such as on-line roulette, were recruited from an on-line crowd-sourcing panel (experiment 1, n = 399; experiment 2, n = 407). Measurements The main dependent variables were a gambler's perceived chances of winning on a seven-point Likert scale (experiment 1) and a multiple-choice measure of warning label understanding (experiment 2). Findings The house-edge label led to lower perceived chances of winning in experiment 1, F(1, 388) = 19.03, P < 0.001. In experiment 2, the house-edge warning label was understood by more gamblers [66.5, 95% confidence interval (CI) = 60.0%, 73.0%] than the return-to-player warning label (45.6%, 95% CI = 38.8%, 52.4%, z = 4.22, P < 0.001). Conclusions House-edge warning labels on electronic gambling machines and on-line casino games, which explain what a gambler might expect to lose, could help gamblers to pay greater attention to product risk and would be better understood by gamblers than equivalent return-to-player labels