Item Response Analysis of the Short Dark Triad Questionnaire
(English)In: ICPS 2017International Convention of Psychological Science, Vienna, Austraia, 23 - 25 March 2017Conference paper (Refereed)
We used Item Response Theory to analyze item functionality in the Short Dark Triad Questionnaire.The responses were less reliable when θ was less than 0, while most reliable when θ was 0-3. The onedeviation from this pattern was narcissism, which showed stable reliability coefficients between -2and 3.Supporting summaryBackground: Character is defined as individuals’ goals and values or what people make ofthemselves intentionally. In this context, Dark Triad Theory suggests that malevolent human charactercomprises: Machiavellianism, psychopathy, and narcissism. These three dark traits are often measuredusing single long instruments for each one of the traits. Nevertheless, there is a necessity of short andvalid personality measures in psychological research. We aimed to expand the understanding of oneof the most popular short Dark Triad measures, namely the Short Dark Triad Questionnaire, usingItem Response Theory to analyze item functionality.Method: Participants (N = 1,487, nmales = 608, nfemales = 879) were recruited from Amazon’sMechanical Turk. Mean age was 33.28, SD = 11.66. They received $0.50 as compensation forparticipating and only residents of the US were allowed to accept participation.Results: We ran three separate unidimensional models, one for each of the dark character traits. Scaleinformation curves revealed that the items deliver most information when θ levels are approximatelybetween 0 and 3. Importantly, the information by the Machiavellianism items, and thus alsoreliability, substantially declines when θ is approximately 2. Reversed items tended to get the lowestalphas, with 4 out of 5 reversed items being in the bottom 7 items. Psychopathy and Machiavellianismitems had both highest and lowest alphas, whereas the narcissism items were more clustered in themiddle. At the highest scale-step (b4), the items with the lowest discriminatory ability also showedmore extreme difficulty, above 3 SD. The same trend could be seen at the lower end (b1). The itemswith the lowest discriminatory ability were more extreme, sometimes below 3 SD. Psychopathy items2 and 7 and Machiavellianism items 1 and 4 stood out as weak items. These four items also had thelowest a-parameter estimates, further confirming their relatively weak characteristics. The betas formost of the psychopathy items imply that the items function the best for people above the mean ontrait psychopathy, whereas both Machiavellianism and narcissism betas were more evenly distributed.Conclusion: The Short Dark Triad is less reliable for low levels (i.e., when θ is less than 0) on thelatent trait, especially for psychopathy. The reliability is highest when θ is between 0 and 3. The onedeviation from this pattern is narcissism, which shows stable reliability coefficients (approximately.80) between -2 and 3 θ.
Dark Triad; Item Response Theory; Short Dark Triad Questionnaire; Machiavellianism; Narcissism; Psychopathy.
IdentifiersURN: urn:nbn:se:hv:diva-10411OAI: oai:DiVA.org:hv-10411DiVA: diva2:1059999