Factor Structure and Further Validation of the 20-Item Short Form of the Obsessive Beliefs Questionnaire.

A 44-item version of the Obsessive Beliefs Questionnaire (OBQ-44) put forward by the Obsessive Compulsive Cognitions Working Group remains the most widely used version of the OBQ, despite research casting doubt on its factorial validity and the existence of a short form (i.e., OBQ-20). In a large sample of undergraduate students (n = 1,210), a bifactor model of the OBQ-20, consisting of a general factor and four specific factors (threat, responsibility, importance/control of thoughts, perfectionism/certainty), was supported as the best-fitting model. None of the examined OBQ-44 models provided adequate fit. The bifactor model of the OBQ-20 was retained in two independent samples (n = 1,342 community adults, n = 319 undergraduate students). The incremental validity of the specific factors of the OBQ-20 beyond the general factor was evidenced across multiple criterion indices, including obsessive-compulsive symptom measures and reactions to a thought-induction task. Results further support use of the OBQ-20.