The Eysenck Personality Inventory (EPI) measures two pervasive, independent dimensions of personality, Extraversion-Introversion and Neuroticism-Stability, which account for most of the variance in the personality domain. Parallel forms are available for pre- and post-experimental or treatment measurement. Each form contains 57 "Yes-No" items with no repetition of items.
The inclusion of a falsification scale provides
for the detection of response distortion.
The traits measured are E-Extraversion,
N-Neuroticism and L- Lie. A revised
form of the EPI is the EPQ-R.