IPT Book Reviews

Title: Assessing Sex Offenders: Problems and Pitfalls   Positive Review Positive Review Positive Review
Author: Terence W. Campbell
Publisher: Charles C Thomas, 2005

Charles C Thomas, Publisher, LTD
2600 South First Street
Springfield, Illinois, 2004
(800) 258-8980
263 pages
Price: $61.95 hard


Following a number of high profile sexually violent crimes in the 1990s, several states passed sexually violent predator (SVP) statutes, targeting high-risk sex offenders who had served their sentences and were about to be released from prison.  Currently there are sexual predator statutes in 16 states.

Although there are variations in the different states' SVP statutes, in general, to commit an individual, the state must prove that (a) the person has been convicted of a relevant sexual offense in the past; (b) the person currently suffers from a "mental disorder" or "mental abnormality" predisposing him to engage in acts of sexual violence; and (c) the person is likely to commit a sex offense in the future.  The civil commitment follows a jury trial.

After the state determines that a sex offender should be considered for possible civil commitment, he is evaluated by a state psychologist.  If probable cause is found, he will be evaluated by another state evaluator and by a defense evaluator.  These professionals are generally psychologists, although some psychiatrists also do evaluations.  The evaluation consists of a lengthy and detailed file review, an interview, sometimes psychological testing, often a rating on the Hare Psychopathy Checklist (PCL-R), and ratings on one or more actuarial assessments.  The amount of face-to-face contact ranges from several hours to none at all when the sex offender refuses to speak to the evaluator.

Since actuarial methods are believed to be the most accurate way of assessing long-term recidivism risk, a variety of actuarial instruments have been developed over the past several years for this purpose.  Evaluators generally use one or more of them in combination with their clinical judgment.  The problem is that these procedures are far from perfect and evaluators seldom include adequate qualifications as to their limitations.

This is the focus of Dr. Campbell's book.  Dr. Campbell agrees the research is clear that actuarial assessment is superior to clinical judgment.  But he argues quite persuasively that none of the actuarial methods for assessing sexual offense recidivism have advanced enough to improve over making predictions based entirely on the base rate.  He notes that unless a prediction scheme has exceptional accuracy, attempting to predict events in a population with a low antecedent probability will inevitably lead to an unacceptable level of false positives.  Unless the base rate for recidivism for sex offenders exceeds 30 percent, barring unusual circumstances, the most accurate prediction will always be that a person will not engage in sexual violence.  But none of the actuarial instrument developed to date have more than modest accuracy.

Dr. Campbell notes the increasing number of SVP commitments and the high costs of these programs and asks two "unavoidable questions" concerning these statutes: "(1) Do these statutes rely on assessments of acceptable accuracy to identify sex offender recidivism risk?  (2) Are the treatment programs available to committed SVPs sufficiently effective?"  The remainder of the book addresses these two questions.  Recidivism risk can be assessed in four basic ways: clinical judgment, guided clinical judgment, actuarial assessments, or adjusted actuarial assessments.  Dr. Campbell examines all of these in detail by asking a series of questions proposed by Thomas Grisso1.

  1. Do SVP assessment procedures now satisfy the heightened scientific standards to which they should be subjected?
  2. Are SVP assessment procedures now sufficiently standardized?
  3. Are there manuals now available for SVP assessment procedures that satisfy applicable standards?
  4. Are the levels of inter-rater reliability for SVP assessment procedures now at an acceptable level?
  5. Are SVP assessment procedures being rushed prematurely into legal proceedings?
  6. In legal proceedings, can SVP assessment procedures survive full disclosure of their limitations?
  7. Do SVP assessment procedures create an appearance of precision that substantially exceeds their actual accuracy?

Dr. Campbell observes that there are unresolved problems undermining the actuarial methods used in sex offender risk assessment.  All of the actuarial schemes stress risk factors and ignore protective factors.  Most of the research, and hence the items, on the actuarial instruments are static factors, that is, factors that will never change, although dynamic factors are extremely important.  None of the actuarial instruments adequately consider age-for the RRASOR and the Static-99 the cut- off age is 25; for the MnSOST -R it is 30.  But the base rate for recidivism is much lower for older sex offenders.

There are other problems with the commonly-used actuarial techniques, which Dr. Campbell addresses in detail, including the disagreements between evaluators about whether to use both the Static-99 and the RRASOR or just the Static-99, the changes in the Static-99 coding rules, and field reliability problems.  He notes the lack of peer review in the MnSOST-R, problems that appeared when it was independently analyzed, and concludes it should not be used.

He explains the receiver operating characteristic (ROC) statistic that is used when determining the classification accuracy of an actuarial procedure.  The ROC methods yield what are called area under the curve (AUC) values, that correspond  to the probability of a recidivist's score exceeding a non-recidivist's score.  But the AUC value does not identify the different levels of sensitivity and specificity at various cutoff scores and for samples with recidivism base rates less than 30 percent, actuarial instruments are no more accurate than relying on the base rate alone.  Using them, however, can create a misleading appearance of classification accuracy.

Dr. Campbell next addresses what he terms "supplementary" assessment procedures, including the Psychopathy Checklist-Revised (PCL-R), Violence Risk Appraisal Guide (VRAG), Sex Offender Risk Appraisal Guide (SORAG) the Minnesota Multiphasic Personality Inventory (MMPI-2) the (Millon Clinical Multiaxial Inventory (MCMI-llI), and the Sexual Violence Risk-20 (SVR-20).  Dr. Campbell concludes that there are no supplementary assessment procedures that elevate the basic actuarial instruments above the threshold of general acceptance.

Most evaluators, however, do not rely exclusively upon actuarial assessments; instead they typically adjust their assessment upward or downward using factors such as completing a treatment program or comments made by treatment staff.  But according to Dr. Campbell this procedure, called "adjusted actuarial assessment" (AAA), amounts to a retreat into clinical judgment and unknown errors of judgment. It does not represent an improvement.

Dr. Campbell next discusses the requirement that the sex offender meet the criteria for a diagnosable mental disorder, or mental abnormality.  He notes the shortcomings with the DSM-IV and observes that its reliance on clinical judgment creates significant problems for SVP evaluators who fail to interview offenders but still give diagnoses.  Completing an actuarial assessment without an interview may be defensible, but making a DSM-IV diagnosis without one is not.  Dr. Campbell points out that the DSM-IV contains no inter-rater reliability data and he discusses problems with the personality disorder and paraphilia diagnoses commonly found in SVP evaluation reports.  He concludes that, like the actuarial techniques, the DSM- IV, when subjected to Grisso's seven questions, falls far short.

Finally Dr. Campbell addresses issues in the the treatment of sex offenders, including informed consent, treatment planning, the relapse prevention model, and other problems with SVP therapy.  Although brief, this chapter provides an excellent overview of the controversies and problems in the treatment provided to the civilly committed sex offenders.  He notes that on average the recidivism risk of offenders undergoing treatment is reduced by only approximately 7 percent.  This assumes the best, most current, state-of -the art treatment.

The final chapter, "ethical obligations," applies the American Psychological Association's ethical standards and testing standards to SVP evaluations.  Dr. Campbell believes that these standards mean that psychologists are ethically required to acknowledge the limitations of the actuarial instruments and other techniques when they write reports and testify concerning their SVP evaluations.

Dr. Campbell's book should be studied by anyone who does risk assessments, not only for SVP evaluations but for sentencing evaluations and conditional discharge considerations.  Whether or not evaluators elect to use actuarial methods, clinical assessments, or some combination, it is incumbent upon them to be familiar with the arguments Dr. Campbell presents in this book.  Psychologists must be able to explain clearly and knowledgeably just what methods they used, why they used them, the research supporting these methods, and the limitations of these methods.

1 Thomas Grisso: Invited address: Ethical issues in evaluations for sex offenders re-offending. Presented at "Sex offender re-offense risk prediction." Madison, WI, Sinclair Seminars, March, 2000.   [Back]

Reviewed by Hollida Wakefield, Institute for Psychological Therapies.

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