How does the phrasing of house edge information affect gamblers' perceptions and level of understanding? A Registered Report

The provision of information to consumers is a common input to tackling various public health issues. By comparison to the information given on food and alcohol products, information on gambling products is either not given at all, or shown in low-prominence locations in a suboptimal format, e.g. the 'return-to-player' format, 'this game has an average percentage payout of 90%'. Some previous research suggests that it would be advantageous to communicate this information via the 'house edge' format instead: the average loss from a given gambling product, e.g. 'this game keeps 10% of all money bet on average'. However, previous empirical work on the house edge format only uses this specific phrasing, and there may be better ways of communicating house edge information. The present work experimentally tested this original phrasing of the house edge against an alternative phrasing that has also been proposed, 'on average this game is programmed to cost you 10% of your stake on each bet', while both phrasings were also compared against equivalent return-to-player information (N = 3333 UK-based online gamblers). The two dependent measures were gamblers' perceived chances of winning and a measure of participants' correct understanding. Preregistered Stage 1 protocol: (date of in-principle acceptance: 28/11/2022). The alternative house edge phrasing resulted in the lowest perceived chances of winning, but the original phrasing had the highest rate of correct understanding. Compared to return-to-player information, the original phrasing had both lower perceived chances of winning and higher rates of correct understanding, while the alternative phrasing had only lower perceived chances of winning. These results replicated prior work on the advantages of the original house edge phrasing over return-to-player information, while showing that the alternative house edge phrasing has advantageous properties for gamblers' perceived chances of winning only. The optimal communication of risk information can act as an input to a public health approach to reducing gambling-related harm.