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Review of "Sexual Predators"

By Robert A. Prentky, Howard E. Barbaree and Eric S. Janus
Routledge , 2015
Review by Lloyd A. Wells, MD, PhD on Feb 23rd 2016
Sexual Predators

I chose to read and review this book because my state, Minnesota, has been ordered by federal court to amend its treatment of sexual offenders.  I viewed it as a necessary chore, but ten pages into the book I began to realize that it is an exceptional and fascinating volume.

          The authors are two forensic psychologists and a law school dean; all three have very long-standing expertise in this field.

          The authors begin with an interesting overview and history of serious sex offenders and offenses and the development of sex-offender laws (in twenty states).  They progress to an examination of metrics used to predict recurrence and dangerousness, with a very heavy (and completely required) dose of statistics, including Bayseian statistics.  The book concludes with a summary of its critique of current approaches and predictions for the future.

There are two recurrent themes.  The first is the conundrum of "the application of group-based data to one individual", which is inevitable in a judicial process involving one offender, and the second is the fact that "the field of sex offender risk assessment remains atheoretical and preparadigmatic, and that a coherent, theoretical framework, when it comes, will presage the next generation of risk assessment."

The initial pages set the scene for a discussion of the role of fear and panic in relation to sexual crimes, with reference to the Salem witch trials, slavery, and the McCarthy accusations.  The authors then briefly describe several heinous sexual criminals of the 1930's and 1940's, and the "moral panic" they triggered in the larger population, often fanned by politicians and others, and leading to the "Sutherland Cycle" in which law is crafted in response to panic.  One phenomenon related to this sort of emotional panic is the frequency with which, after a heinous sexual crime enacted on a child, a new law is passed -- often maned for the child -- but these laws are often bad laws.  Although the risk to the population is negligible, politicians craft law in response to public fear and disgust.

In the next chapter, the authors discuss the development of specific sexual predator laws, looking first at laws aimed at preventing harm by those of "outsider" status -- e.g. sterilization of the retarded, World War Two Japanese-American internment -- and court decisions which upheld these laws.  Certainly, laws to keep sexual offenders away from society after their criminal sentences have been completed are similar and based on the same belief of danger to society.  Sexual offenders have a 13% recidivism rate, lower than for many other crimes, but the issue lies in predicting whether a given offender will fall in the 13% or the 87%.

The authors next provide a compelling chapter on the interface of the law and science, which is also about the law, science, and politics.  In a telling vignette, they describe a well conducted study which provided data consistent with the hypothesis that not all sexually abused children are irrevocably harmed (a study which has been confirmed in many subsequent studies):  the U. S. House of Representatives "denounced" the study with a vote of 355 to zero.  The sponsor of this resolution stated that the study was "the emancipation proclamation of pedophiles".  The Family Research Council decided that the paper's publisher "needs to root out the pro-pedophilic academicians who are trying to normalize child abuse."  The topic is obviously fraught with intense emotions, and it is difficult to engage in rational, scientific discourse in such a matrix.

The next chapter introduces the instruments and methods used in assessing the likelihood of future violence in sex offenders.  A great many measures are used, most of them much better than the old standard of a psychiatrist predicting violence on the basis of a lengthy clinical interview -- this never worked very well.  Subsequent chapters provide much more information on how these measures are developed and evaluated.  This understanding requires knowledge of statistics, which the authors provide at length and quite brilliantly.  Their explanation of the relevant statistics is both comprehensible and, with effort, it provides a fairly sophisticated understanding, which is important.  The authors discuss some of the problems with an actuarial approach, but this approach has contributed significant findings, including the reduction of recidivism with age of the offender, rapists being younger than child molesters, and antisocial orientation being more common in young offenders while sexual deviance is more common in older ones.  These are important findings.

But the science and the statistical predictors do not stand alone -- they must be weighed and interpreted in the courtroom, along with much else.  The authors provide several pages on the problem of "black swans" -- incredibly rare events such as memorably heinous sexual crimes.  As an example, thirty times more children are murdered by family members than by sexual predators.  The authors examine this phenomenon from many perspectives, including statistical and predictive ones.

The statistical part of the book is very long but has multiple anecdotes and applications to the book's topic.

The next chapter is on policy, law, and costs, with an initial consideration of violence as a public health problem.  The cost component is staggering.  Virginia paid sixty-two million dollars (in 2008) for a facility to house sixty committed sexual offenders.  In North Dakota, it cost just under $140,000 to treat one committed offender for a year.  The cost of a sexual offender trial in Minnesota exceeds $100,000.  An offender in Washington placed on a provisional release cost the state $740,000 for one year.

The next chapter provides advice for the future in service and forensic practice, with excellent advice on how to testify, and how to pose categorical vs probabilistic expressions of risk.  There is a very brief consideration about applying these metrics to juveniles.

Thus, after introducing the topic, the authors provide an excellent overview of the development of sexual offender laws, mandated treatment, and the concomitant ethical and legal problems, the development and deployment of tests and measures used to predict recidivism and dangerousness, and some informed ideas about the future.

There are many positive features of this book.  The explications of the many laws and how far beyond the usual protections of citizenship they extend, and the contexts in which they developed, are truly well done and thought-provoking.  The several chapters explaining statistical methods lead to the possibility of truly understanding them, which is necessary to understand the book.  Throughout the book, anecdotes and case examples are timely and relevant.

I found only two faults with the book.  The three authors clearly worked together to write different chapters, but there is occasional redundancy.  And the long, excellent explanation of relevant statistics, while a strength of the book, is likely tedious for many readers.

This book is not for everyone, but it does an excellent job of explaining current laws and metrics applied to sexual offenders, and it raises troubling questions about their continued incarceration long after their criminal sentences have expired.  I learned a great deal.


© 2016 Lloyd A. Wells


Lloyd A. Wells, M.D., Ph.D., Emeritus Consultant, Mayo Clinic