The Performance of College Students on the Iowa Gambling Task: Differences Between Scoring Approaches

The Iowa Gambling Task (IGT) is one of the most common behavioral decision-making tasks used in clinical and research settings. Less-than-expected performance among healthy adults generates concerns about the validity of this task, and it is possible the particular scoring approach utilized could impact interpretation. We examined how performance patterns changed across several scoring approaches, utilizing a large, college student sample, both with (n = 406) and without (n = 1,547) a self-reported history of psychiatric or other diagnosis. Higher net scores were seen when participants selected decks with a low loss frequency than decks with high long-term outcomes; however, participants overall underperformed the IGT normative data sample. Receiver operating characteristic curves examining multiple scoring approaches revealed no threshold of impaired performance that both maximized sensitivity and minimized false positive rate on the IGT. Scoring approach matters in the determination of impaired decision making via the IGT in adults.