Responsible product design to mitigate excessive gambling: A scoping review and z-curve analysis of replicability

A systematic review of conference papers presented at two large Japanese psychology conferences in 2013 and 2018: did Japanese social psychologists selectively report p < 0.05 results without peer review?

We conducted a systematic review of conference papers in social psychology at two large psychology conferences in Japan: the Japanese Psychological Association and the Japanese Society for Social Psychology. The conference papers were effectively not subjected to peer review; hence, they were suitable for testing if psychologists selectively reported statistically significant findings without pressure from journal editors and reviewers. We investigated the distributions of z-values converted from the p-values reported in the articles presented at the 2013 and 2018 conferences. The z-curve analyses suggest the existence of selective reporting by the authors in 2013. The expected discovery rate (EDR) was much lower than the observed discovery rate (ODR; 7% vs. 76%, respectively), and the 95% confidence interval (CI) did not include the ODR. However, this does not mean that the set of studies completely lacked evidential value. The expected replication rate (ERR) was 31%; this is significantly higher than 5%, which was expected under the null hypothesis of no effect. Changes were observed between 2013 and 2018. The ERR increased (31% to 44%), and the EDR almost doubled (7% to 13%). However, the estimation of the maximum false discovery rate (FDR; 68% in 2013 and 35% in 2018) suggested that a substantial proportion of the reported findings were false positives. Overall, while social psychologists in Japan engaged in selective reporting, this does not mean that the entire field was covered with false positives. In addition, slight signs of improvement were observed in how they reported their findings. Still, the evidential value of the target studies was weak, even in 2018, allowing for no optimism.

The Effect of a Mandatory Play Break on Subsequent Gambling Behavior among British Online Casino Players: A Large-Scale Real-World Study

In recent years, various novel responsible gambling (RG) tools have been implemented to aid harm-minimization. One such RG tool has been the implementation of enforced mandatory play breaks. Despite many responsible gambling operators using mandatory play breaks, only three previous studies have examined their efficacy and the findings were mixed. Therefore, the present investigation was a large-scale real-world study which was designed to see whether a 60-minute mandatory play break influenced subsequent depositing and wagering. The authors were given access to 27 days of player data prior to the introduction of a mandatory play break and 27 days of player data after the mandatory play break was introduced. The study comprised British online gamblers from Skillonnet (a European online gambling operator). Between July 23 and September 15 (2021), 2,021 players deposited at least ten times or more on a calendar day, at least once. The 2,201 players generated 2,994 corresponding events (i.e., the depositing of money at least 10 times in one day). The percentage of players who stopped depositing money as a consequence of the mandatory play break rose from 27% to 68% on the day of a play break. Moreover, the percentage of players who stopped wagering as a consequence of the mandatory play break rose from 0.1% to 45% on the day of a play break. The findings of the present study demonstrated that a 60-minute mandatory play break impacts players' depositing and wagering immediately after the play break. This means that a mandatory hour-long play break in an online casino setting appears to prevent overspending during a short period of time. The effects of a 60-minute mandatory break on the next day's behavior were inconclusive.