Why polygraph testing of sexual offenders is not an effective treatment strategy
On May 9, the Colorado legislature passed House Bill 1427, which prohibits individuals with a vested economic interest in administration of polygraph tests from serving on the sex offender management board (SOMB). Beyond the issue of conflict of interest, there are other reasons to keep polygraph out of sex offender treatment decisions. The primary reasons are issues with reliability and the coercive nature of compelling disclosures about thoughts and activities (legal or illegal).
Polygraph testing in post-conviction sex offender treatment (PCSOT) is used in approximately 80% of community-based sex offender treatment programs. This high rate of use continues despite the fact that in 2003 the National Research Council found little support for the accuracy of polygraph, particularly when used for screening purposes, as it is in PCSOT. The lack of scientific support for polygraph testing is why the results are generally not admissible in court. Despite this lack of scientific support, some proponents of polygraph are unconcerned with the accuracy, reliability, or validity of the testing as long as it gets people to confess to deviant thoughts and “risky” behaviors.
There is no objective way to measure the accuracy of the polygraph, but proponents claim the value is in increased disclosure of information and deterrence of offending. However, claims about the value of polygraph as a deterrent to offending are not supported by research. Increased disclosure of information is also not supported as having either treatment or deterrence value. In fact, a 2007 study found that there was no difference in recidivism rates between sexual offenders who were subjected to polygraph and those who were not. Contrary to the purported value of increased disclosures, there is no evidence increased disclosures means decreased offending.
Decades of research regarding the use of polygraph have failed to show improvement in its reliability. Yet very little research has been dedicated to exploring whether or how polygraph improves treatment outcomes or reduces recidivism rates of sexual offenders. Despite the known problems of reliability, and unsupported claims of efficacy in treatment and deterrence, the use of polygraph in PCSOT continues to be upheld by courts around the country as a legitimate tool in depriving individuals of their Constitutional rights and subjecting them to additional punishment.
The lack of scientific support for the use of polygraph in PCSOT should be of serious concern where individuals are at risk of being deprived of their freedom. Polygraph testing may be most effective in coercing individuals to provide socially desirable answers in an effort to be seen as scrupulously truthful. In addition, therapists who work with these offenders may be compelled to provide information to the polygraph examiner that is then used to formulate test questions. In virtually any other type of psychological treatment, this kind of coercion and sharing of information disclosed in therapy would raise significant ethical concerns. Yet in the “treatment” of sexual offenders, these questionable practices can, and do, result in further legal actions or other sanctions against the convicted offender, with little discussion about ethics.
The Colorado legislature rightly took steps to put an end to what appears to be a conflict of interest on the part of certain members of the SOMB. Perhaps without the influence of people who have economic interests in administering polygraph tests, the SOMB might consider whether polygraph testing is in fact an effective use of the millions of dollars it spends on this testing. In terms of improving treatment outcomes and reducing recidivism, polygraph testing simply has not been demonstrated to be effective. Colorado and other states might be better advised to invest taxpayer dollars in research regarding effective treatment and management strategies, rather than continuing to fund use of a tool that does not support those goals.
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 National Research Council. (2003). The Polygraph and Lie Detection. Washington, D.C.: National Academies Press. https://doi.org/10.17226/10420.
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 Osher, C. (May 14, 2017). Colorado’s pricey polygraph testing of sex offenders under fire as critics target accuracy, expense. The Denver Post. Retrieved from https://www.denverpost.com/2017/05/14/colorado-does-not-require-polygraph-testing-of-most-parolees-but-sex-offenders-get-different-treatment/.