The study aimed to estimate and compare the psychometric properties of the Portuguese versions of two irrational-beliefs self-report measures: the Irrational Belief Questionnaire (IBQ) and the Irrational Belief Scale (IBS). Eight hundred fourty nine college students completed both instruments besides the Goldberg's General Health Questionnaire (GHQ), used as external criterion of the discriminant validity. Results show that both instruments have good internal consistency and test-retest reliability, but none of them correlated significantly with the GHQ. The IBS principal component analysis points to a single-factor structure with 16 out of the 20 scale's items high loading on the same factor in at least one of the groups according to the sex and the general sample. It is suggested that the IBS should be preferred to the IBQ for assessing irrational beliefs of Brazilians subjects and that further research on validity should be carried out .
Irrational beliefs; irrational beliefs assessment; psychometric properties; validation; reliability
