The Unified Narcissism Scale-Revised: Testing Incremental Validity and Shortening the Measure.

Narcissism has had a long history of conceptual and measurement confusion. In this paper, we aimed to assess the incremental and external validity of the Unified Narcissism Scale-Revised (UNS-R), and to determine a prototype short form of the measure that is invariant across cultures. In Study 1, we constructed a 15-item short form prototype that was scalar invariant across four countries (United States, China, Sri Lanka, and Australia). Using this short form, we found the Australian sample to be the most different from the other samples. We speculate this is due to Australia having a more horizontal culture, demonstrating resistance to hierarchy and a stronger endorsement of equality. In Study 2, we assessed the incremental and external validity of the UNS-R long and short form and found it to be a superior measure of grandiose narcissism in terms of strength and cogence of external correlations compared to existing measures, but the Five-Factor Narcissism Inventory-Short Form (FFNI-SF) was a better measure of vulnerable narcissism. In conclusion, we have illustrated the robustness of the UNS-R, and its short form, as a measure of narcissism and, in the process, highlighted important cross-cultural differences.