Dredging the OCEAN.20 : an item response theory analysis of a shortened personality scale

Abstract

Valid and reliable personality assessments are important tools for personnel selection, so long as they are efficient and free from bias (Mount & Barrick, 1995). Undergraduate students (N = 503) completed the OCEAN.20, a brief 20-item self-report measure of the five factors of personality (O’Keefe, Kelloway, & Francis, 2012). Classical test theory methods had already established the scale’s reliability and validity, as replicated in the present study, but item response theory analyses identified nine problematic items. Three items displayed differential item functioning, three items had a truncated range of responses, and three more items had low precision. The potential for bias or insufficient information offered by each item is cause for concern, as it could have serious consequences in determining a job applicant’s fate, so it is advised that these items either be removed or revised prior to operational use. Limitations and recommendations for future research are discussed.