An instrument for measuring psychopathy, developed by the Canadian criminologist Robert D(ouglas) Hare (born 1934) and published commercially in 1991, based on an earlier Psychopathy Checklist (PCL) that he published in the journal Personality and Individual Differences in 1980. It comprises 20 items associated with behavioural, affective, and interpersonal attributes of psychopathy, taken from the classic description of the syndrome in The Mask of Sanity: An Attempt to Reinterpret the So-called Psychopathic Personality (1941) by the US neuropsychiatrist Hervey (Milton) Cleckley (1903–1984). Each item is scored from 0 (not applicable) to 2 (highly applicable) on the basis of a semi-structured interview and collateral file review. Factor analysis of scores from the Psychopathy Checklist and the Psychopathy Checklist-Revised has consistently identified two correlated but distinct factors, the first associated with affective and interpersonal attributes, such as superficial charm, selfishness, callousness, manipulativeness, pathological lying, lack of empathy, and shallow affect, and the second associated with socially deviant behaviour and lifestyle, including proneness to boredom, parasitic lifestyle, impulsivity, early behavioural problems, irresponsibility, and delinquent behaviour. The range of possible scores is 0–40, and the conventional cut-off score for diagnosing psychopathy is 30. According to this criterion, a person with true psychopathy has both an emotional disorder and a propensity to manifest antisocial behaviour. Hare found that 28 per cent of male prison inmates in the US scored at or above this cut-off score, and research in the UK has found a similar proportion. Also called the Hare Psychopathy Checklist. PCL-R abbrev.