How personality profile similarity can improve comparability between assessment formats: An example of the Mini-IPIP and IPIP-NEO-120 in a Dutch community sample.

Background. There is a growing interest to unravel the genetic and brain structural underpinnings of personality by pooling data for mega- and meta-analyses within international consortia. Consequently, it is of increasing importance to evaluate the consistency of personality traits across assessment formats and languages. In this study, we evaluated the profile similarity framework as a means to compare personality profiles assessed using different inventories.Methods. We first assessed the psychometric properties of the Dutch translations of the 20-item Mini-IPIP and 120-item IPIP-NEO-120, both completed by 822 volunteers. We then applied the profile similarity framework to compare the personality factors and profiles obtained using the Mini-IPIP and the IPIP-NEO-120. Results. The psychometric properties and factor structure of the Dutch translations resembled the original English questionnaires well. The correlations between the personality profile scores were shown to be more robust and less format-dependent than the correlations between personality factors. This improvement was maintained when accounting for profile normativeness. Conclusions. These findings show the way to more consistent personality factors and profiles obtained across different assessment formats and languages. The method promises increased sensitivity and reliability in large-scale international collaborative studies on the underlying mechanisms of the five-factor personality model.