What SD3 measures
SD3 estimates Machiavellianism, grandiose narcissism, and subclinical psychopathy with nine statements per scale. The constructs overlap, and later research has questioned how cleanly some scales separate.
How scoring works
Responses run from 1 to 5. Five items are reverse-scored. The nine keyed responses for each trait are averaged, producing three values from 1.00 to 5.00; there is no overall Dark Triad score.