High agreement was obtained across scores from multiple equated scales for social anxiety disorder using item response theory

Objectives: There is no standardized approach to the measurement of social anxiety. Researchers and clinicians are faced with numerous self-report scales with varying strengths, weaknesses, and psychometric properties. The lack of standardization makes it difficult to compare scores across populations that use different scales. Item response theory offers one solution to this problem via equating different scales using an anchor scale to set a standardized metric. This study is the first to equate several scales for social anxiety disorder. Study Design and Setting: Data from two samples (n 5 3,175 and n 5 1,052), recruited from the Australian community using online advertisements, were used to equate a network of 11 self-report social anxiety scales via a fixed parameter item calibration method. Results: Comparisons between actual and equated scores for most of the scales indicted a high level of agreement with mean differences !0.10 (equivalent to a mean difference of less than one point on the standardized metric). Conclusion: This study demonstrates that scores from multiple scales that measure social anxiety can be converted to a common scale. Rescoring observed scores to a common scale provides opportunities to combine research from multiple studies and ultimately better assess social anxiety in treatment and research settings