Item Properties and the Validity of Personality Assessment

The aim of the current research was to evaluate psychometric properties of personality questionnaire items that can affect their validity, as measured by comparing self-ratings with roommate ratings on a series of personality questionnaires. The item properties under investigation included item content saturation, item social desirability, and mean item responses. Archival data collected between 1981 and 2004 representing various groups of same-sex undergraduate roommate dyads were used for the purpose of this research. Results demonstrated that item content saturation was the most consistent predictor of item response accuracy. Mean item responses also predicted accurate responding curvilinearly, with moderate mean item responses eliciting the most accuracy. In order to better predict outcome variables in education, clinical, and vocational contexts using scores on personality questionnaires, it is important for researchers to employ item selection procedures that take into account the specific item properties that we know can affect personality test validity