Development and Validation of Ideas of Reference About Body and Appearance Scale (IRBAS) for the Spanish Population

Ideas of Reference (IR) are self-directed attributions about social interactions, where people interpret the behaviors of others as being aimed at them. Particularly, those IRs related to the body and appearance are crucial. This study approaches the need to create and develop an instrument that specifically allows analyzing the Ideas of Reference about Body and Appearance (IRBAS). Pilot studies were conducted, and the IRBAS was subjected to validation in two non-clinical Spanish samples (N = 2,049). Content validity was assessed by an expert panel (N = 6). Exploratory and confirmatory factor analyses were carried out, and the internal consistency and stability of the instrument were evaluated, as well as convergent and known-groups validity. The IRBAS showed a unidimensional structure with high internal consistency and temporal stability. The analyses confirmed its invariance as a function of sex and level of education, and its correlation with measures of body dissatisfaction, dysmorphic concerns, schizotypy, and shame. Moreover, differences were confirmed in the scores of the IRBAS between sexes and between different categories of body mass index. The IRBAS proved to be a reliable and valid tool for the evaluation of IRs about the body and appearance in a non-clinical population.