The Dark Triad is dead, long live the Dark Triad: An item-response theoretical examination of the Short Dark Tetrad

Research on the Dark Tetrad (Machiavellianism, narcissism, psychopathy, and sadism) is burgeoning. Therefore, psychometrically sound measures are required to ensure that predictions based on these constructs are reliable and valid. A recently devised scale to assess all traits simultaneously is the Short Dark Tetrad (SD4; Paulhus et al., 2021). Previous studies demonstrated the general suitability of the SD4 in terms of classical test theory, but item response theoretical (IRT) analyses are still missing, whereby IRT approaches extract more information on the items and scales and tests assumptions untested in classical test theory. Thus, we evaluated the subscales of the SD4 using IRT modeling (N = 594). Unlike the sadism subscale, the Machiavellianism, narcissism, and psychopathy subscales had satisfactory fit of the two-parameter polytomous IRT models and provided ample information across the respective trait continua. The sadism subscale, however, exhibited problems related to item discrimination (i.e., in differentiating between individuals with similar levels) and item (category transition) difficulties (i.e., quantifying how “difficult” it is to endorse higher compared to next lower response categories). The results thus emphasize the need for a thorough revision of the items of the sadism scale.