Second-order factor structure of the Vancouver Obsessive Compulsive Inventory (VOCI) in a non-clinical sample

The Vancouver Obsessive Compulsive Inventory (VOCI) is a self-report measure of the severity of obsessive-compulsive problems such as contamination, checking, obsessions, hoarding, needing things to be just right, and indecisiveness. In the seminal paper a six-correlated-factor structure was found in a sample of OC patients, but the issue of the factor structure of the VOCI in non-clinical populations was not addressed.

This study assesses the psychometric properties and the factor structure of the Italian version of the VOCI in a non-clinical sample.

The VOCI was administered to a large community sample (n = 445). Some participants also completed a battery including measures of OC behaviour, worry, anxiety and depression (n = 89) and were administered the VOCI twice at an 8-week interval (n = 46).

Confirmatory factor analyses replicated the six-correlated-factor structure originally found in a patient sample, but a more parsimonious, second-order-factor model showed a statistically higher fit, suggesting that VOCI subscales can be considered as facets of a higher-order OCD factor. The whole item pool and each of the subscales showed good internal consistency, unidimensionality, test-retest reliability and convergent construct validity. As in the original version, limited support for discriminant validity was found. Scores were weakly associated with age, gender and education.

Although some key issues still need to be investigated (e.g. sensitivity to change), the VOCI seems to be a psychometrically sound instrument for the assessment of OCD-related behaviours and thoughts and can be used in cultural contexts different from the original.