Designing a brief measure of social anxiety: Psychometric support for a three-item version of the Interaction Anxiousness Scale (IAS-3)

Although social situations are enjoyable for most people, they cause extreme anxiety in others. To better understand individual differences in social anxiety, researchers have designed scales, such as the 15-item Interaction Anxiousness Scale (IAS; Leary, 1983), to measure people’s anxiousness in social situations. Despite the importance of measuring social anxiety, many research settings that require time or space constraints (e.g., field, longitudinal, daily diary studies) cannot always accommodate a 15-item scale. To address this problem, the current research aimed to create and validate a three-item version of the IAS. Studies examined the psychometric properties of a three-item measure of social anxiety (IAS-3). After choosing the best three items using item response theory methods (Study 1), we examined the IAS-3’s (a) concurrent validity with the 15-item IAS in a student sample (Studies 1 and 2), (b) test–retest reliability across 4 months (Study 2), and (c) construct validity in a diverse international sample (Studies 3 and 4). Across all studies, the IAS-3 showed good reliability and validity, supporting its use in future research.