The reliability, validity, discriminant and predictive properties of the social phobia inventory (SoPhI)

Abstract

This paper reports on the psychometric properties of the Social Phobic Inventory (SoPhI) a 21-item scale that was designed to measure social anxiety according to the criteria of DSM-IV (American Psychiatric Association, APA (1994) Diagnostic and Statistical Manual of Mental Disorder, 4th Edn., Washington). Factor analysis of the SoPhI using data from a clinical sample of respondents with social phobia revealed one factor which explained approximately 59% of variance and which demonstrated strong internal reliability (α= 0.93). The SoPhI demonstrated concurrent validity with the SPAI (r= 0.86) and convergent validity with the Fear of Negative Evaluations-Revised (r=0.68). The predictive utility of the scale was demonstrated in a sample of university students classified as extroverted, normal, shy/introverted, and phobic/withdrawn (η2 57%). Multivariate Analysis of Variance (MANOVA) revealed that the combined university sample differed from the clinical sample on the summated scores on the SoPhI and that 43% (η2) of this difference was attributable to group membership. This figure rose to 58% attributable to group membership when these same groups were compared for differences on the 21 individual items. Scores of the SoPhI that are indicative of concern and of possible diagnostic criteria, as well as suggestions for future research, are discussed.