The Stability of Gambling Expenditure Distributions Over Time and Associations with the Use of Gambling Self-regulatory Tools

Research about the distribution of gambling activity and what percentage certain subgroups of gamblers are responsible for is mixed, but all indicates that a small minority (i.e., the vital few) is responsible for a greater amount of gambling activity than the large majority (i.e., the trivial many). The present pre-registered study extends this line of research to a large dataset of digital gambling records for a cohort of sports bettors from Europe (n = 36,331) over a 6-year period (2015–2020) to examine (1) whether distributions based on amount wagered and net loss in this cohort change over time on a yearly basis, (2) the extent to which individuals are stable or change their distribution group membership from the vital few to the trivial many (and vice versa) over time, and (3) how distribution group membership predicts the use of a cool-off feature (i.e., a temporary break from being able to gamble on the website) and self-exclusion (i.e., permanent exclusion from the gambling website). We observed that gambling expenditure distributions were mainly stable over time. Individual distribution group membership varied, such that the size of the vital few comprised 3 to 6.5% of active users each year. The largest subgroup was an early churn subgroup (i.e., stopped playing after the first year; about 66% of the sample), followed by people who remained in the trivial many for their study period (i.e., the stable trivial; 21 to 22%). Moving between distribution groups over time was strongly associated with using cool-off or self-exclusion features. Our findings have important implications for understanding the distributions of gambling spending among sports gamblers, the extent to which membership in high-spending groups remains stable over time, and potential risks for responsible gambling tool use and gambling-related problems.