The German EPP-D : How to Shorten and Improve the Reliability and Validity of Eysenck’s Personality Profiler (EPP)

Abstract

In this study we evaluated a German version (EPP-D) of the Eysenck Personality Profiler (EPP). The EPP measures 21 traits, seven for each of Eysenck’s superfactors Extraversion, Emotionality (Neuroticism), and Adventure/Caution (Psychoticism). Each of these scales consists of 20 items with a trichotomous response scale (yes/can’t decide/no in the English original and yes/no/don’t know in the German translation). The 420-item questionnaire was completed by a sample including employees, university students, and high-school students ( N = 2,006; mean age 31 years). The study applied three strategies: 1) abandoning the indifferent response category “don’t know,” 2) excluding missing values from the data analysis, which were coded equal to the indifferent response category, and 3) considering the results of item analyses including information on construct validity gained through confirmatory factor analyses (CFA). Findings from the EPP-D indicate that 155 items are sufficient to gain satisfactory psychometric properties of 15 primary scales (five traits each assigned to the superfactors). The EPP-D 155-item version has advantages in quality of data and administration time compared to the original EPP 420-item version.