The second edition of the PCL-R test, originally designed by the controversial maverick Canadian criminologist Robert Hare in 1980 and again in 1991, contains 20 items designed to rate symptoms which are common among psychopaths in forensic populations (such as prison inmates or child molesters). It is designed to cover the major psychopathic traits and behaviours: callous, selfish, remorseless use of others (Factor 1), chronically unstable and antisocial lifestyle (Factor 2), interpersonal and affective deficits, an impulsive lifestyle and antisocial behaviour.
The twenty traits assessed by the PCL-R score are: glib and superficial charm; grandiose (exaggeratedly high) estimation of self; need for stimulation; pathological lying; cunning and manipulativeness; lack of remorse or guilt; shallow affect (superficial emotional responsiveness); callousness and lack of empathy; parasitic lifestyle; poor behavioral controls; sexual promiscuity; early behavior problems; lack of realistic long-term goals; impulsivity; irresponsibility; failure to accept responsibility for own actions; many short-term marital relationships; juvenile delinquency; revocation of conditional release; and criminal versatility.
Psychopaths score between 30 and 40. Normal people score between 0 and 5. But Hare himself was known to label as psychopaths people with a score as low as 13. The PCL-R is, therefore, an art rather than science and is leaves much to the personal impressions of those who administer it.
The PCL-R is based on a structured interview and collateral data gathered from family, friends, and colleagues and from documents. The questions comprising the structured interview are so transparent and self-evident that it is easy to lie one’s way through the test and completely skew its results. Moreover, scoring by the diagnostician is highly subjective (which is why the DSM and the ICD stick to observable behaviours in its criteria for Antisocial or Dissocial Personality Disorder).
The hope is that information gathered outside the scope of the structured interview will serve to rectify such potential abuse, diagnostic bias, and manipulation by both testee and tester. The PCL-R, in other words, relies on the truthfulness of responses provided by notorious liars (psychopaths) and on the biased memories of multiple witnesses, all of them close to the psychopath and with an axe to grind.
The PCL-R is not the only bad apple in an otherwise healthy crop. Psychological tests are far from scientifically rigorous.
Personality assessment is perhaps more an art form than a science. In an attempt to render it as objective and standardized as possible, generations of clinicians came up with psychological tests and structured interviews. These are administered under similar conditions and use identical stimuli to elicit information from respondents. Thus, any disparity in the responses of the subjects can and is attributed to the idiosyncrasies of their personalities.
Moreover, most tests restrict the repertory of permitted of answers. “True” or “false” are the only allowed reactions to the questions in the Minnesota Multiphasic Personality Inventory II (MMPI-2), for instance. Scoring or keying the results is also an automatic process wherein all “true” responses get one or more points on one or more scales and all “false” responses get none.
This limits the involvement of the diagnostician to the interpretation of the test results (the scale scores). Admittedly, interpretation is arguably more important than data gathering. Thus, inevitably biased human input cannot and is not avoided in the process of personality assessment and evaluation. But its pernicious effect is somewhat reined in by the systematic and impartial nature of the underlying instruments (tests).