Boelen, P. A. & Baars, L. Y. (2007). Psychometric properties of the Belief Scale, a measure of irrational thinking. European Journal of Psychological Assessment, 23, 133-140.
This study examined psychometric properties of the Belief Scale - a 20-item self-report measure of irrational beliefs as conceptualized in rational-emotive behavior therapy (REBT). Data were available from 293 inpatients. Confirmatory factor analysis showed that the items of the Belief Scale formed eight distinct irrational belief components which were related to one higher order factor. The Belief Scale demonstrated adequate internal consistency and concurrent validity. In support of the discriminant validity, items of the Belief Scale and indices of psychopathology clustered into two distinct factors in exploratory factor analysis. In support of the construct validity, scores on the Belief Scale decreased more in patients who underwent training in REBT during their inpatient treatment than in those who did not.