Development and Initial Validation of an Inconsistent Responding Scale for the Youth Psychopathic Traits Inventory.

The Youth Psychopathic Traits Inventory (YPI) is widely used in research, but there currently exist no means to identify potentially invalid protocols resulting from careless or random responding. We describe the development of an inconsistent responding scale for the YPI using three archival samples of youths, including two from the United States (juvenile justice and middle school) and one from Germany (vocational training school). We first identified pairs of correlated YPI items and then created a total score based on the sum of the absolute value of the differences for each item pair. The resulting scale strongly differentiated between genuine protocols and randomly generated YPI data (n = 1,000) across samples (AUC values = .88-.92). It also differentiated between genuine protocols and those same protocols after 50% of the original YPI items were replaced with random data (AUCs = .77-.84). Scores on this scale also demonstrated fairly consistent patterns of association with theoretically relevant correlates.