Item Response Theory Analysis of the Dark Factor of Personality Scale for College Students in China.

The Dark Factor of Personality (D) describes the common core of dark traits and is a stable indicator for socially aversive behaviors. This study investigated the psychometric properties of the Chinese version of the Dark Factor of Personality Scale for college students using item response theory (IRT). A total of 762 students-251 males and 511 females ( = 19.99, = 1.30)-were recruited. Item response theory methods were utilized to evaluate the properties of the scale. Four items with poor item properties were excluded, obtaining a final 28-item scale (D28-C) that included highly discriminative items showing high measurement precision in various levels of the D factor. Furthermore, a test of differential item functioning (DIF) by gender was conducted. The result indicated that the scale as a whole could be seen as gender invariant. Lastly, according to the detailed information provided by IRT and the content of items, a reliable short form of the D28-C comprising 15 items was obtained. The study enriched the existing knowledge of the dark factor of personality in the Chinese background and made some revisions to the corresponding scale to make it a more reliable tool for measurement in China. In addition, the shortened version of the scale based on item information and content helps to improve the efficiency of the measurement.