The Eysenck Personality Questionnaire, or E.P.Q., measures the three traits described in the personality theory of Hans Eysenck. These are extraversion, psychoticism and neuroticism. It was published, in revised form, by Eysenck, Eysenck and Barrett (1985) in the journal Personality and Individual Differences. A different approach to personality measurement developed by Eysenck, which distinguishes between different facets of these traits, is the Eysenck Personality Profiler.

Reference

• Eysenck, H.J., Eysenck, S.B.G. & Barrett, P. (1985). A revised version of the psychoticism scale. Personality and Individual Differences, 6, pp. 21-29.