Encyclopedia of Psychology and Law

There is good evidence that the PCL–R is a very

reliable instrument when administered and scored by

trained and experienced raters. Internal consistency is

high (alpha coefficient is greater than .80). The intra-

class correlation (ICC) typically exceeds .80 for a sin-

gle rater (ICC 1 ) and .90 for the average of two raters

(ICC 2 ). The standard error of measurement (SEM) of

the PCL–R total score is approximately 3 for a single

rating and 2 for the average of two ratings.

The PCL–R also has good generalizability across

diverse forensic populations, although there may be sex,

ethnic, and cultural differences in the way some features

of psychopathy are manifested. Recent research sug-

gests that the construct underlying the PCL–R is dimen-

sional in nature, but a cut score of 30 has proven useful

as a working definition of psychopathy. The utility of

cut scores for clinical and forensic purposes will be

influenced by the context in which the PCL–R is used

(e.g., research, diagnosis, risk assessment, treatment

options).

Although there is good evidence that the PCL–R

measures a unitary construct, the items can be grouped,

logically and statistically, into several correlated dimen-

sions or factors. Recent confirmatory factor analyses of

very large data sets clearly indicate that a four-factor

model (18 items) fits the data well: Interpersonal

(Glibness/superficial charm, Grandiose sense of self-

worth, Pathological lying, Conning/manipulative); Affec-

tive(Lack of remorse or guilt, Shallow affect, Lack of

empathy, Failure to accept responsibility for actions);

Lifestyle(Need for stimulation/proneness to boredom,

Parasitic lifestyle, Lack of realistic long-term goals,

Impulsivity, Irresponsibility); and Antisocial (Poor

behavioral controls, Early behavior problems, Juvenile

delinquency, Revocation of conditional release, Criminal

versatility). Two other items (Promiscuous sexual behav-

ior, Many short-term marital relationships) do not load

on any factor but contribute to the total PCL–R score.

Some commentators have suggested that the Antisocial

factor is a measure of criminality and that it is a manifes-

tation of the more central features of psychopathy. In

reality, it reflects a pattern of persistent and serious rule-

breaking behavior. Clinical tradition, as well as recent

findings from behavioral genetics and developmental

research, clearly indicates that antisocial dispositions are

an integral part of the construct and its measurement.

Association With Other Measures

Psychopathy, as measured by the PCL–R, is treated by

some as being equivalent with the DSM-IV(Diagnostic

and Statistical Manual of Mental Disorders, fourth edi-

tion) diagnosis of antisocial personality disorder

(APD). However, the diagnostic criteria for APD place

greater emphasis on antisocial behaviors than does the

PCL–R and are more closely associated with the

Lifestyle/Antisocial components of psychopathy than

with its Interpersonal/Affective features. Most of those

with APD do not have high PCL–R scores (i.e., in the

30 +range). Psychopathy and APD are related but not

identical constructs.

The PCL–R is moderately correlated, in expected

directions, with various self-report measures of psy-

chopathy and with several omnibus personality scales.

These instruments make it easy to collect large

amounts of data and are beginning to play a role in

delineating and elucidating the nomological network,

behavioral genetics, and developmental pathways of

psychopathy. They also provide support for the view

that psychopathy is an extreme variant of normal per-

sonality dimensions.

Validity

The validity of the PCL–R in the criminal justice sys-

tem is well established, a reflection of the central and

pervasive role of psychopathy in criminal behavior.

There is extensive evidence for the explanatory power

and utility of the PCL–R in the prediction of recidi-

vism, violence, and treatment outcome in criminals

and in forensic and civil psychiatric populations. The

PCL–R routinely is used in risk assessments, either on

its own or, more appropriately, as part of a battery of

variables and factors relevant to offending and vio-

lence. Besides forensic and applied areas, evidence

for the validity of the PCL–R is provided by findings

obtained from a wide variety of laboratory,

cognitive/affective, and neuroscience paradigms,

including functional magnetic resonance imaging.

Current Issues

The widespread acceptance of the PCL–R as the prin-

cipal method for assessing psychopathy and its fre-

quent description as the “gold standard” have led

some commentators to express their concern that the

measure has become the construct. The remedy is to

introduce and validate supplementary or improved

assessment methods. A more pressing concern is the

potential for misuse of the PCL–R in the forensic con-

text. Because assessments of psychopathy can have

serious consequences for the individual and society, it

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