Big Five Inventory-2; facets; personality assessment; factor analysis; sex invariance; Rasch analysis; validity

The Big Five Inventory-2 (BFI-2) is one of the most used questionnaires to assess personality traits, distinguishing 15 facets. Despite its usage, there is still room for research to improve its psychometric properties. We applied the Rasch analysis (RA) to transform the BFI-2 into an instrument consisting of actual interval scales (obtaining the BFI-2-R), involving 5362 Italian adults. Five confirmatory factor analyses supported the three-facet structure of each trait. This structure resulted invariant at the scalar level across sex.