The Psychopathy Checklist (PCL; Hare, 1980) consists of 22 items. The Psychopathy Checklist � Revised was developed by Hare, R.D. in 1985, and was formally published in 1991. The 20-item revision of the Psychopathy Checklist (PCL-R) is a rating scale designed to measure traits of psychopathic personality disorder. The two versions of the PCL have much the same psychometric properties (Harpur, Hare, & Hakstian, 1989).
The instrument can be used to aid in making a diagnosis of psychopathy or can be a trait measure of psychopathic personality (Hare, Harpur, Hakstian, Forth, Hart, & Newman, 1990).
The PCL-R was originally developed for use in experimental psychopathy (Cooke, Michie, Hart, & Hare, 1999). The PCL was derived from a factor analysis of characteristics (e.g., callousness) and historical items (e.g., criminal versatility) based on the clinical conception of psychopathy detailed in Cleckley�s (1976) The Mask of Sanity.
Qualifications and training:
The PCL-R manual (Hare, 1990) outlines the recommended qualifications for clinical use of the instrument. They include: possession of an advanced degree in the social, medical, or behavioral sciences, such as a Ph.D., D.Ed. or M.D. Registration with a state or provincial body that regulates the assessment and diagnosis of mental disorder as well as experience in working with forensic populations is required. Adequate training and supervised experience in the use of the PCL-R is also required.
Type of Instrument and Scoring Method:
The PCL�R is a 20-item clinical rating scale, each item reflects a different symptom or characteristic of psychopathy. The items are rated on a 3-point scale (0 = item doesn�t apply, 1 = item applies somewhat, 2 = item definitely applies). The items are rated on the basis of the person�s lifetime functioning and not solely on the basis of the person�s present state; this state may be atypical of his/her usual functioning due to extreme situational factors or an exacerbation of acute psychopathology.
The items are summed to yield total scores, ranging from 0 to 40, that reflects the degree to which an individual resembles the prototypical psychopath. Scoring PCL-R items requires clinical judgement and inference, as well as the ability to carry out the task in an objective, professional manner (Hare, 1998). A cutoff score of 30 or greater (in some studies 25) is used to diagnose psychopathy. The PCL-R items are scored on the basis of an individual�s functioning over most of the life span. This means that a clinician or researcher who wants to measure change in psychopathic symptomatology during incarceration cannot use the PCL-R.
The standard error of measurement for the PCL-R is approximately three points (Hare, 1998).
The PCL-R: Standard Errors of Measurement
Reliability Estimate SEM1 SEM3
Note: SEM1 = Standard error of measurement
SEM3 = Standard error of prediction
GC = Generalisability coefficient
(Source: Hare, 1990).
In research on psychopathy, it is often necessary to identify groups of inmates with high, medium, and low levels of psychopathy using specific cut off scores (Wong, 1988). Analysis of variance indicated that the overall difference between low, medium, and high psychopathy groups was highly significant, F(2, 298) = 208.9, p < .001; post hoc comparisons (Scheffe) revealed that each group differed significantly from the other (Schroeder, Schroeder, & Hare 1983).
The items can also be summed to yield scores on two distinct, yet moderately correlated (.5) factors (Harpur, Hakstian, & Hare, 1988). The two factors have proven to be reliable and are replicable across institutions and countries (Hart, & Hare 1989). Factor 1 of the PCL�R reflects the affective and interpersonal features of psychopathy. Factor 1 has been labeled the Selfish, Callous, and Remorseless Use of Others. The items in this factor are concerned with impressions and inferences about interpersonal processes and are typically scored using both file information and impressions formed during the interview. In particular, this factor reflects the psychopath�s verbal and interpersonal style.
Factor 2 reflects social deviant behaviors and has been labelled Chronically Unstable and Antisocial Lifestyle (Zagon, & Jackson, 1994). The items that define the factor predominately depend on identifying the occurrence of specific behaviors, most often using the inmate�s file.
Items in the Hare Psychopathy Checklist - Revised
Item Factor Loading
Glibness/superficial charm 1
Grandiose sense of self-worth 1
Need for stimulation/proneness to boredom 2
Pathological lying 1
Lack of remorse or guilt 1
Shallow affect 1
Callous/lack of empathy 1
Parasitic lifestyle 2
Poor behavioral control 2
Promiscuous sexual behavior -
Early behavior problems 2
Lack of realistic, long-term goals 2
Failure to accept responsibility for own actions 1
Many short-term marital relationships -
Juvenile delinquency 2
Revocation of conditional release 2
Note : A dash indicates the item does not load on either factor.
(Source: Cooke, Michie, Hart, & Hare, 1999)
The PCL�R is completed on the basis of a semi-structured interview of 90 to 120mins duration. The PCL-R can be scored on the basis of file information alone, provided that the material contained in the files is extensive and detailed. Wong�s (1988) study found that reliable ratings of psychopathy can be obtained based on comprehensive file information alone (Pearson r = .74). The interrater reliability and the mean ratings obtained without the benefit of the interview are not significantly different from that obtained using interviews (Z = -.91, ns). It is important to note, that the PCL-R cannot be scored on the basis of an interview alone (Hare, 1998).
The PCL-R is costly to administer in terms of time and effort, as access to detailed interview and case history information, including criminal record is required. These considerations led to the development of the Screening Version of the PCL-R (PCL:SV; Hart, Cox, & Hare, 1995). However, the PCL-R is regarded as the instrument of choice for measuring psychopathic personality disorder (Cooke, & Michie, 1997). Fulero (1995) described the PCL-R as the �state of the art, both clinically and in research use.�
The PCL�R takes approximately 2 hours for a trained interviewer to complete a PCL-R evaluation based on a semi-structured clinical interview and file information (Grann, Langstrom, Tengstrom, & Stalenheim, 1998).
The PCL-R �s psychometric properties are well established with male offenders and forensic patients (Hare, 1996), and to an increasing extent, with female (Strachan, 1994), and adolescent offenders (Forth, Hart, & Hare, 1990).
The PCL-R has been used with only a few samples of female offenders. Early indications from several studies are encouraging. Thus far, it appears that the distribution of scores and reliability are comparable with those obtained in male samples. However, it appears that several items may not be as useful with female offenders as they are with male offenders (Hare, 1990). Neary (1990) administered the PCL-R to 120 female inmates of the Federal Prison. The mean score for the sample was 21.1 (SD = 6.5), the interrater reliability was.94, the alpha coefficient was .77 and the mean inter-item correlation was .14.
Stauchan, Williams, & Hare (1990) administered the PCL-R to 40 female inmates of Lakeside Correctional Institute in British Columbia. The mean total scores pooled across two raters was 24.9 (SD = 7.2), the interrater reliability was .95, the alpha coefficient was .79 and the mean inter-item correlation was .19.
Interestingly, the sex of the rater appears to make little difference in the PCL and PCL-R assessments of male inmates or forensic patients.
Although the PCL-R was developed for use with adults, there is evidence from a study conducted by Forth, Hart, & Hare (1990) indicating its use in the assessment of psychopathy in young male offenders. The results of the study show the interrater reliability and internal consistency to be high. The ICC for single and average ratings was .88 and .94 respectively. The alpha coefficient was .90 and the mean inter-item correlation was .33.
Reliability:
� Cronbach�s Alpha
Hare, (1991) argued that within North America the PCL-R shows considerable homogeneity. Classical indices of reliability (alpha coefficients, inter- and intra-rater reliability) ranged from .82 to .93. In a study conducted by Hare, Harpur, Hakstian, Forth, Hart, & Newman (1990) analyses of data from five prison samples (N = 925) revealed inter-rater reliability, intraclass correlation coefficients were .78 to .94 (M = .86) for a single rating and from .87 to.97 (M = .93) for the average of two ratings. Internal consistency was assessed by Cronbarch�s coefficient alpha, which ranged from .87 to .97 (M = .88). These results indicate that the PCL-R is a homogeneous, unidimensional scale.
A study conducted by Harpur, Hare, & Hakstian (1989) examined data on 937 inmates of several prisons in Canada, and the United States and on 80 male patients in a Canadian forensic psychiatric facility. The mean correlation among the items on the PCL for samples 1 to 3 were .29, .23, and .24 respectively. These values are all consistent with the use of the PCL as a homogeneous, unidimensional scale. Similarly, the statistical values of Green, Lissitz, & Mulaik (1977) for the three samples (.78, .78, and .72) are indicative of a high degree of homogeneity.
� Test-Retest Reliability and Inter-rater Reliability
The test-retest reliability of the PCL instrument has shown to be high, as evidenced in five published studies (Schroeder, Schroeder, & Hare, 1983). The generalizability coefficients were .85, .86, .90, .86, and .89 for the years 1977-1981, respectively. The generalizability coefficient for a test-retest study was .89.
Summary of Generalizability Coefficients and Classical Test Score Indices of Reliability Obtained in Five Studies.
Study N Rater 1 Rater 2 Interrater Reliability GC
1977 72 .84 .82 .93 .85
1978 71 .83 .84 .92 .86
1979 47 .90 .92 .91 .90
1980 44 .86 .87 .84 .86
1981 58 .90 .90 .88 .89
Note: GC = generalizability coefficient.
(Source: Schroeder, Schroeder, & Hare, 1983).
The results indicate that the instrument is a very reliable (generalizable) instrument when used with prison populations.
Cacciola, Rutherford, & Alterman (1990) examined the temporal stability of the PCL-R in a sample of 10 male opiate addicts attending a methadone clinic. These patients were assessed at intake, and then reassessed by a second rater (blind to the intake assessment) after a period of one month. The test-retest reliability of the PCL-R total scores was .94. Although, based on a small sample, the test-retest reliability is similar to that reported by Schroeder, Schroeder, & Hare, 1983.
According to Hare (1998) properly conducted assessments should routinely produce inter-rater reliabilities (intra-class correlations) of at least .80 for the PCL-R.
� Item Reliability
The PCL-R: Mean Interrater Reliability, Corrected Item Total Correlations, &
Descriptive Statistics for each Item
Item Inter-rater Item Total M SD
Glibness/Superficial Charm .55 .48 .79 .75
Grandiose sense of self worth .54 .52 .85 .76
Need for stimulation/ .61 .57 1.39 .72
Pathological lying .46 .54 .96 .76
Conning/manipulation .61 .57 1.02 .79
Lack of remorse of guilt .60 .51 1.45 .70
Shallow affect .54 .53 1.15 .75
Callous/lack of empathy .52 .61 1.25 .72
Parasitic lifestyle .58 .39 1.11 .70
Poor behavioral control .62 .42 1.23 .78
Promiscuous sexual behavior .62 .38 1.12 .85
Early behavior problems .65 .43 .99 .85
Lack of realistic long-term goals .57 .46 1.28 .74
Impulsivity .56 .51 1.52 .66
Irresponsibility .51 .51 1.41 .68
Failure to accept responsibility .42 .39 1.17 .78
for own actions
Many short-term marital .66 .30 .67 .79
Juvenile delinquency .79 .36 1.12 .89
Revocation of conditional release .73 .35 1.31 .80
Criminal versatility .86 .42 .92 .82
Note: N = 1632 (Source: Hare, 1990)
� Predictive Validity
The value of the PCL-R in forensic and clinical settings is supported by evidence of its predictive validity. The PCL-R scores predict a variety of antisocial behaviors, including criminal violence (Cooke, & Michie, 1997), violent recidivism following release from prison or hospital (Harris, Rice, & Quinsey, 1993), and poor treatment response to correctional treatment programs (Ogloff, Wong, Greenwood, 1990). According to Serin (1992), the PCL-R is equal to actuarial risk scales in predicting general recidivism, but is superior in predicting violent recidivism.
Psychopathic criminals tend to commit more crimes and are more violent that non-psychopaths. Hare & McPherson (1984a) performed a discriminate analysis in which 20 of the PCL items were used to discriminate between groups of inmates classified as violent or nonviolent on the basis of their criminal records. The discriminate functions were highly significant.
Correlates of the PCL: Percentage of Inmates convicted of Violent Crime
Crime Category High Medium Low
Murder 5.5 5.3 10.1
Possession of a weapon 34.2 24.0 13.9
Robbery 49.3 44.0 21.5
Assault 45.2 22.7 19.0
Kidnapping 12.3 4.0 1.3
Vandalism 16.4 2.7 6.3
Fighting 15.1 8.0 1.3
Any violent crime 84.9 64.0 54.4
N 73 75 79
Inmates� behavior while incarcerated correlated significantly more with factor 2 than with factor 1 of the PCL in a study conducted by Harpur, Hare, & Hakstian (1989).
Correlates of the PCL Factors and Performance Variables
Variables N 1 2 PCL Total Score Za
Institutional 313 .33 .50 .49 3.61
Conditional Release 231 .18 .38 .33 3.47
Note : Za Testing the difference between the correlation�s of Factor 1 and Factor 2 with the variable. P =
Correlates of the PCL: Percentage of inmates who displayed violent and aggressive behavior in prison
Behavior High Medium Low
Attempted suicide 19.2 10.7 15.4
Self-mutilation 6.8 4.0 3.8
Verbal abuse 24.7 9.3 3.8
Verbal threats 26.0 9.3 9.3
Easily annoyed/irritated 45.2 28.0 10.3
Belligerent 46.6 21.3 3.8
Aggressive Homosexuality 6.8 8.0 2.6
Fighting 50.7 29.3 26.9
Any of the above 86.3 80.0 55.1
N 73 75 79
A study conducted by Hart, Kropp, Hare (1988) concluded that psychopaths were more likely to violate the conditions of their release than non-psychopaths and the PCL total scores were found to be useful in predicting release outcome. Hart, Kropp, & Hare (1988) reported that criminal psychopaths were four times more likely than non-psychopaths to fail release. Harris, Rice, & Cormier (1989) noted that the PCL correctly identified 80% of violent recidivists in a maximum-security psychiatric sample. A study by Grann, Langstrom, Tengstrom, & Gunnar (1999) found that psychopaths were at about twice the risk for recidivism relative to non-psychopaths. The relative risk for violent recidivism was 1.98 (95%). Salekin, Rogers, & Sewell (1996) described the predictive ability of the PCL-R as �unparalleled and unprecedented� in the assessment of dangerousness.
Response To Treatment
Ogloff, Wong, & Greenwood (1990) evaluated the progress of 80 male forensic patients enrolled in a therapeutic community program designed to treat personality-disordered offenders. PCL-R scores were used to divide the patients into high (scores 27+), medium (18+), and low (17 and below) psychopathy groups. The results showed that the high psychopathy group differed significantly from each of the other groups. On average, the high psychopathy group remained in the program for a shorter period of time, put in less effort, and showed less improvement, than did either of the others groups.
� Content Validity
The items of the PCL-R are generally consistent with traditional and current clinical views on the personality traits and behaviors that define the construct of psychopathy. The pattern of total scores is consistent with clinical descriptions of the psychopath as superficial, callous, exploitative, egocentric, emotionally shallow, non-anxious, and with little evidence of psychotic symptoms. Global clinical ratings and Checkley�s core criteria for psychopathy correlated highly with Factor 1 and Factor 2 (Hare, 1990).
� Construct Validity
The PCL-R has good construct validity. A study conducted by Hart and Hare, (1989) examined the association between psychopathy and other mental disorders (Axis I and Axis II criteria of the DSM-111) in 80 male forensic patients. The results showed the inter-rater reliability (between raters A & B) for the PCL-R total scores was .91. The average total score of raters A & B were 21.97 (SD = 6.76). The internal consistency of these final ratings (Cronbach�s alpha) was .86. Preliminary analyses suggested that the factor structure of the PCL-R was identical to that obtained in criminal, non-psychiatric populations.
In summary, PCL-R total scores were positively correlated with ratings of antisocial, histrionic, and narcissistic personality disorder and negatively correlated with ratings of avoidant personality disorder. The significant association between the PCL and antisocial personality disorder is consistent with extensive data on the construct validity of the PCL in male prison populations (Harpur, Hakstian, & Hare, 1988 and Newman, & Kosson, 1986).
In addition, the most widely used psychiatric category related to psychopathy is Antisocial Personality Disorder (APD). Although, the PCL and APD are designed to measure a more or less common construct and are significantly correlated with one another, they are not equivalent or interchangeable. A diagnosis of APD depends on almost entirely on evidence of antisocial behaviors, and, as a result, base rates in forensic populations are typically above .5. In contrast, the PCL measures both personality traits and antisocial behaviors; base rates for PCL defined psychopathy in forensic populations are low, typically around 1.5 to .20 (Harpur, Hare, & Hakstian).
� Convergent Validity
Convergent validity for the PCL-R has been demonstrated by its strong relationship (.70 to .083) with DSM-III diagnosis of antisocial personality disorder (Hare, 1983).
� Discriminate Validity
Research on the discriminate validity of psychopathy diagnoses has important theoretical and practical implications. It may yield clues concerning the position of psychopathy in a hierarchical structure of mental disorders. It may also help to improve predictions about future behavior and response to treatment in cases where disorders are thought to co-exist. With respect to forensic issues, it may also help clinicians to differentiate individuals who are legally �insane� and thus incompetent to stand trial and/or not criminally responsible (Hart, & Hare, 1989).
The association between psychopathy and axis II measures of the DSM-III in Hart, & Hare (1989) study were low enough to support the discriminate validity of the PCL. This study also found that the pattern of correlations between the PCL and schizophrenia, ratings of other personality disorders, BPRS, and GAS scores provided further evidence for the discriminate validity of the PCL. PCL total scores were either uncorrelated or negatively correlated with these measures.
Correlations Between Prototypicality Ratings of DSM-111 Disorders and Psychopathy Checklist (PCL) Scores
DSM- 111 prototypicality ratings Total Factor 1 Factor 2