Coimbra Obsessive Inventory – short version

Development and psychometric properties

Abstract

The Coimbra Obsessive Inventory is a self-report instrument encompassing two 50-items scales aimed to assess obsessive-compulsive symptoms frequency and emotional disturbance/discomfort. Being a long instrument, the development of a reduced version was considered relevant. Thus, the current study aimed to develop a short version of the Coimbra Obsessive Inventory (IOC-R), and explore its psychometric characteristics. According to psychometric criteria, the IOC-R included 19 items, distributed by five subscales – “Contamination/Washing”, “Indecision/Slowness”, “Repeated checking/Hoarding”, “Immoral content” and “Magical thinking”. Confirmatory factorial analysis of the IOC-R 5-factor model was conducted in a sample of 338 individuals from the general population. Fit indexes showed that the model presented a good fit to the data. Analysis of IOC-R internal consistency proved to be excellent. Test-retest reliability was indicative of adequate temporal stability. Furthermore, the IOC-R revealed a strong correlation with the Padua Inventory, which also assesses obsessive-compulsive symptoms, and moderate correlations with the Anxiety, Depression and Stress Scales. To sum, the IOC-R may be a valid and reliable self-report instrument, easy to use, both in clinical and research settings.