Inconsistent or careless responding to self-report measures is estimated to occur in approximately 10% of university research participants and may be even more common among offender populations. Inconsistent responding may be a result of a number of factors including inattentiveness, reading or comprehension difficulties, and cognitive impairment. Many stand-alone personality scales used in applied and research settings, however, do not include validity indicators to help identify inattentive response patterns. Using multiple archival samples, the current study describes the development of an inconsistent responding scale for the Triarchic Psychopathy Measure (TriPM; Patrick, 2010), a widely used self-report measure of psychopathy. We first identified pairs of correlated TriPM items in a derivation sample (N = 2,138) and then created a total score based on the sum of the absolute value of the differences for each item pair. The resulting scale, the Triarchic Assessment Procedure for Inconsistent Responding (TAPIR), strongly differentiated between genuine TriPM protocols and randomly generated TriPM data (N = 1,000), as well as between genuine protocols and those in which 50% of the original data were replaced with random item responses. TAPIR scores demonstrated fairly consistent patterns of association with some theoretically relevant correlates (e.g., inconsistency scales embedded in other personality inventories), although not others (e.g., measures of conscientiousness) across our cross-validation samples. Tentative TAPIR cut scores that may discriminate between attentively and carelessly completed protocols are presented.