Measuring the irrational and rational beliefs of sport fans: Development and validation of the Sport Fan Beliefs Inventory (SFBI)

Since the 2010s, Rational Emotive Behavior Therapy (REBT) has been increasingly applied to understand emotions, thoughts, and behaviors in sport contexts; however, the rational and irrational beliefs of sport fans remain largely unexplored. This study aimed to develop the Sport Fan Beliefs Inventory (SFBI) to assess rational and irrational beliefs among sport fans in Türkiye. The inventory was developed and evaluated across five studies, providing comprehensive evidence of its reliability and validity. Confirmatory factor analysis supported a structure comprising two higher-order factors - rational and irrational beliefs - and eight subdimensions consistent with REBT theory. Convergent and discriminant validity analyses showed that fan anger, aggression, hatred, and depression were positively associated with irrational beliefs and negatively associated with rational beliefs. Test-retest reliability, assessed with 87 fans over a two-week interval, indicated stable scores with no significant differences. Additionally, a single-session REBT intervention was administered to 15 fans and compared with a control group of 15, demonstrating increased rational beliefs and decreased irrational beliefs in the intervention group. Overall, the findings provide strong evidence for the reliability and validity of SFBI scores, highlighting the inventory's potential utility for applying REBT principles to sport fan populations.