A discussion of modern versus traditional psychometrics as applied to personality assessment scales.

Item response theory (IRT) methods are used by large testing firms, state agencies, and school districts to construct, analyze, and score most major aptitude, achievement, proficiency, entrance, and professional licensure exams. Personality assessment, in contrast, has not generally adopted these more powerful, modern psychometric techniques. We evaluate the possible role of IRT in the personality domain by highlighting key areas in which IRT and traditional methods differ. Although we conclude that IRT has a significant role to play in future personality measurement, there are many systemic and technical barriers to its routine application.