The present work consists of two studies. In the first study, a new abbreviated form of the EPQ-R (six items per scale) was developed from the 100 items of the full-length version of the questionnaire. Methods and procedures developed within the framework of multidimensional IRT were used for this purpose. In the second study, the abbreviated questionnaire was validated on a new data sample. In addition, latent profile analysis was used to identify groups of individuals characterized by similar patterns of the four PEN-L traits. These patterns were also compared with respect to indicators of psychosocial functioning. Results indicated that the new abbreviated form of the questionnaire outperforms the old abbreviated form with respect to reliability and approximation of measures obtained with the full-length test. Moreover, the four-factor structure of the instrument and its convergent validity have been confirmed. Three PEN-L patterns have been identified that differ for anxiety and depression, satisfaction for social relations, frequency of substance use and sexual risk behaviors.
Eysenck’s questionnaires are among the most used instruments for the assessment of personality (Eysenck & Eysenck, 1991). Over the years, several contributions have been offered for the refinement of these questionnaires and for the development of brief versions for both adult and young people (e.g., Francis, 1996; Francis, Brown, & Philipchalk, 1992; Francis & Pearson, 1988). The short forms of the Eysenck Personality Questionnaire-Revised (EPQ-R; Eysenck & Eysenck, 1991; Eysenck, Eysenck, & Barrett, 1985) assess the four PENL (Psychoticism, Extraversion, Neuroticism, Lie) traits through 48 items (12 per scale; Corulla, 1990; Eysenck, Eysenck, & Barrett, 1985; Francis & Pearson, 1988). Although the short forms of the EPQ-R were explicitly developed “for use when time is very limited” (Eysenck, Pearson, Easting, & Allsopp, 1985; p. 24), it has been argued that, in some cases, these forms could still be too long, thus leading researchers to exclude the assessment of some personality traits (Francis et al., 1992). Consequently, abbreviated forms of the EPQ-R have been developed that include 24 items only (6 per scale; Francis, 1996; Francis et al., 1992). In general, research provided evidence about the cross-cultural validity of these instruments and their acceptable psychometric properties. However, some criticisms have also been raised. For instance, concerning the abbreviated form of the EPQ-R (Francis et al., 1992), different studies highlighted not fully satisfactory reliability, mainly for P and L scales (Forrest, Lewis, & Shevlin, 2000; Shevlin, Bailey, & Adamson, 2002). In addition, other studies showed that several items of P, N, and L scales might exhibit differential item functioning (DIF) across gender (e.g., Escorial & Navas, 2007; Forrest et al., 2000; Karanci, Dirik, & Yorulmaz, 2007), which makes the comparison between groups questionable.