A large-scale prospective study of big wins and their relationship with future financial and time involvement in actual daily fantasy sports contests.

OBJECTIVE Early big wins might have a psychological impact upon gamblers that increases their likelihood of intemperate gambling; however, there has been a paucity of empirical research examining this effect using actual gambling data. METHOD We assessed the effects of daily fantasy sports (DFS) big wins on subsequent play by analyzing a prospective dataset from a major DFS provider (N = 34,596 DFS subscribers) representing over 18 million entries into DFS contests. RESULTS We found that experiencing a big win in DFS is associated with subsequently increased DFS engagement (i.e., increased contest entry fees and contest entries) and losses (i.e., higher net loss). However, the effect of a big win on engagement and losses decays over time. Whereas theorists have highlighted the effects of early big wins, our analyses indicated that later big wins had a relatively stronger effect on DFS engagement. Sensitivity analyses confirmed the robustness of most results, with somewhat greater support for big wins' effects on engagement metrics than losses. CONCLUSION Our results collectively indicate the existence of a big win effect in DFS. For some players, big wins might instill unrealistic expectations about future probabilities of winning and lead to increased-and potentially excessive-engagement. Explanations from cognitive psychology (e.g., the illusion of control) and behavioral psychology (e.g., operant conditioning) might help to explain the big win effect. (PsycInfo Database Record (c) 2021 APA, all rights reserved).