Psychometric appraisal of the Scale for Interpersonal Behavior (SIB) in France

The present study was carried out in France to evaluate the reliability and validity of the Scale for Interpersonal Behavior (SIB), a multidimensional measure of difficulty and distress in assertiveness that was originally developed in The Netherlands. This appraisal was conducted with a clinical sample (N = 166) and a general population sample (N = 150). The clinical series comprised 115 patients with social phobia and 51 patients with personality disorder, 28 of whom were of the avoidant type. Support was found for internal consistency and test-retest reliability of the French SIB. Compared to controls, both social phobics and patients with an avoidant personality disorder had significantly lower mean scores on all performance scales and significantly higher ones on all distress scales, with the social phobics occupying a position in between. Findings in relation to convergent and divergent validity were quite satisfactory. Sensitivity of the French SIB for detecting change was demonstrated in a subgroup of the clinical Ss who had undergone 15 sessions of cognitive-behavioral group therapy for underassertiveness.