Sexual Predator Evaluations and Phrenology:
Issues of Evidentiary Reliability
Terence W. Campbell, Ph.D. [*]
Behavioral Sciences and the Law, 18: 111-130 (2000)
used methods for risk assessment
This article reviews six assessment procedures used for assessing the recidivism risk of previously convicted sexual offenders. The review of these procedures examines whether they comply with generally accepted ethical and practice standards. With few exceptions, most risk assessment instruments fail to comply with these standards. Currently used instruments for risk assessment continue to rely excessively on clinical judgment; and, as a result, they remain at a preliminary stage of development. Consequently, these instruments amount to experimental procedures; and, therefore, they cannot support expert testimony in a legal proceeding.
response to public outrage provoked by highly publicized sexual assaults,
various states have enacted sexual predator legislation (including but not
limited to Arizona, California, Florida, Illinois, Kansas, Minnesota, North
Dakota, Ohio, Washington, and Wisconsin). These laws call for a civil hearing to
determine whether a previously convicted sexual offender should be indefinitely
committed for treatment. If committed for treatment as a sexual predator, the
individual remains confined until another hearing finds that his response to
treatment warrants release. Sexual predator laws also typically require that two
or more psychologists or psychiatrists evaluate the previously convicted
Sexual predator evaluations typically proceed in a step-wise manner to address three questions:
Sexual predator evaluations therefore raise questions regarding the evidentiary reliability of the assessment methods used to evaluate previously convicted offenders. In other words, do these assessment procedures possess sufficient evidentiary reliability to support expert testimony in a legal proceeding?
for example, that a psychologist testifying in a sexual predator hearing
premises his or her opinion on a phrenological assessment of a previously
of course, is an entirely discredited method of personality assessment involving
measurements of the shape and curvature of the head). Relying on phrenology,
the psychologist concludes that the previously convicted offender does -- or
does not -- qualify for civil commitment as a sexual predator.
obviously, any court would disallow the testimony of a psychologist using
phrenology in the manner described above. Phrenology is neither generally
recognized, nor generally accepted, for psychological or psychiatric assessment.
Instruments generally used for risk assessment are obviously more reliable than
phrenology. The question remains, however, whether those instruments are sufficiently
more reliable than phrenology to allow them into evidence in asexual
[*] Correspondence to: Terence W. Campbell, Ph.D., 4105 Metro Parkway, Ste 103, Sterling Heights, Ml 48310, USA; e-mail address: terence.campbeI13@gte.net