Carolyn MacCann

The “Dirty Dozen” is a popular, brief, self-report scale to capture individual differences in the Dark Triad traits (i.e., narcissism, Machiavellianism, and psychopathy). While the scale has good psychometric properties, there has not yet been an examination of informant ratings for this instrument, despite the apparent utility of informant ratings for providing an observer’s perspective on a target’s personality. We present evidence for the validity of an informant-rated version of the Dirty Dozen – the Dark Informant-Rated Triad (DIRT). Across two studies ( n study1 = 281; n study2 = 395 dyads), we found evidence for structural validity (i.e., a three-factor model fits the data well), as well as convergent, discriminant, and criterion-related validity of the DIRT, as well as strong self-informant agreement. We propose future research should examine sources of self-informant disagreement and the extent to which informant-reported Dark Triad trait scores may differ depending on the situation (work vs. home) or informant type (colleague vs. spouse).