Normative studies with the Scale for Interpersonal Behaviour (SIB): III. Psychiatric inpatients

The Scale for Interpersonal Behaviour (SIB), a multidimensional self-report measure of difficulty and distress in state assertiveness, was psychometrically evaluated in a large sample comprising 1242 unselected psychiatric inpatients. In addition to an overall measure of assertion, the SIB contains four factorially-derived dimensions: (I) negative assertion, (II) expression of and dealing with personal limitations, (III) initiating assertiveness, and (IV) positive assertion. The factors were originally interpreted in data of 703 members of a society for phobic individuals. Evidence is presented on the factorial constancy of the SIB measuring constructs across samples, biological sex, age, and educational level. Outstanding internal consistency figures are also given. Construct validity is established in a subset of the inpatients in relation to the Assertion Self-Statement Test-Revised. Both descriptive and specialized norms are presented for psychiatric inpatients.