Wilcox, et al., (1999b) described the different types of post-conviction polygraph examinations and their purposes. They note that specific issue post
conviction testing is very beneficial to the therapist when an individual is
denying or substantially minimising events surrounding the index offence. There is a very high success rate in obtaining admission of wrong doing from offenders once they have undergone a polygraph examination. Salter (1997b) noted that they no longer have ‘denier groups’ in Oregon and Washington because of the effectiveness o f the polygraph in breaking down denial.
Maintenance and monitoring testing, also known as Compliance testing, is also regarded as very useful for Probation Officers, treatment workers and the individual completing his Probation Order to ensure that the requirements of therapy and the Probation Order are adhered to consistently.
Sexual Histoiy Disclosure testing enables the treatment worker to understand
more about the subject’s general sexual history and importantly any previously undisclosed sexual interests and activities. By uncovering the details concerning past sexual history, a more focused treatment approach can be developed. Commonly, disclosure tests reveal other deviant past sexual behaviour beyond the range of the index offence. This procedure may also reveal crossing over o f deviant sexual interests to include both genders or different target age groups. This knowledge may be of particular interest where child protection issues are a central concern in Care and Family Proceedings.
Ahlmeyer, et al.,. (2000) advised that the post-conviction application of the polygraph should be seen against a broad backdrop of often intense and pervasive denial amongst sexual offenders who are extremely reluctant to disclose their offending histories for a variety o f psychosocial and legal reasons. English, et al.,. (1996) argued that the polygraph has a significant
impact on this ‘wall of denial’, accruing demonstrable benefits with adult sex offenders. Indeed, they reported that this tool has shown such promise that it has gradually been applied to other sexual offending populations, including adolescents and the intellectually disabled.
Chambers (1994) and Emerick and Dutton (1993) found the polygraph a valid adjunct to their assessment and treatment programmes for adolescent offenders. Holden (1999) reported the routine use of the polygraph with sex offenders in the state o f Texas in conjunction with treatment and supervision requirements, and he noted that the polygraph’s application to adolescent sexual offenders is now mandatory.
Researchers Hare, R.D., (personal communication, November 3, 1999); and others (e.g. Holden, 1997; Matte, 1996; and Raskin, Barland and Podlesny, 1978) have also reported positive indications about the use of the polygraph with psychopaths (Hare, 1991). This has particular significance in Britain in light o f the recently introduced Mentally Disordered and Severe Personality Disordered Offender Legislation (Department of Health, 1998 and Sex Offender Act, 1997). This legislation mirrors earlier similar laws adopted in the United States concerning Personality Disordered Sexual Offenders (Hendricks, 1997) and calls for increased powers to monitor, assess, treat and, as required, detain psychopathic sexual offenders.
Holden (1996), spoke to the American Association for the Treatment of Sexual Abusers conference in 1996 and reported that the effectiveness and accuracy o f the polygraph is such that even individuals with Mood Disorders or under the influence o f substances can be successfully polygraphed without compromising validity (Matte, 1996). Sosnowski (2000) provided further clarification about the essential requirements of reliable and valid polygraph testing. He noted that when the polygraph examiners are properly trained and qualified, extraneous variables have little impact on the utility and accuracy of
polygraph examination, ‘providing the subject is mentally sound enough to distinguish the truth from lies’. Sosnowski, D (personal communication, July 14, 1988) advised that individuals who suffer from severe Psychiatric Disorders, which markedly impact on their perceptions of the world around them, (i.e. producing hallucinations, delusions, severe thought disorder/disturbance and other reality testing difficulties), would be the exception as they may have a genuinely reduced capacity to accurately gauge what is true because o f distorted views of themselves and the world.
English (1999) set out standards for the employment o f the polygraph examination with adult sexual offenders who have developmental/intellectual disabilities in the state o f Colorado. She identified both procedural and professional training requirements for polygraphing individuals with special needs, indicating positive results when polygraphists are appropriately qualified.
The polygraph is being used regularly in the USA to assess compliance with other conditions of probation as well as offence-related factors such as, the use o f drugs and alcohol or the presence o f masturbatory/deviant sexual fantasies. Approximately one quarter of all sexual offender Treatment Programmes in the USA routinely use the polygraph in conjunction with sex offender treatment according to English, Jones, Patrick, Pasini-Hill and Gonzalez
(2000).
1.5 Standards
As with any other scientific procedure, the polygraph examination should only be conducted by a properly trained polygraphist since the validity o f the procedure will certainly be compromised if this common sense safeguard is ignored. Gelb (1998) advised o f the particular need for specialised training and expertise in Post-conviction Sexual Offender Testing (PCSOT) to avoid polygraph errors. Advanced training requirements have now been strongly
endorsed by Dutton (2000) who chairs the PCSOT sub-committee of the American Polygraph Association (APA) and these specialised requirements have now been formally adopted by the APA.
1.6 Accuracy
In the past seventy-five years, over 250 studies have been conducted on the accuracy o f polygraph testing. Since many different conditions and factors are involved in the research, and since a polygraph examination is a very complex process, it is difficult to draw from the data a specific figure for the accuracy of polygraph testing in all settings. Ansley (1990), investigated validity and reliability o f polygraph testing, compiling the results o f ten studies conducted between 1980 and 1990. He reported that:
Examiner decisions in these studies, were compared to other results such as confessions, evidence and judicial disposition. The ten studies reviewed considered the outcome of 2,042 cases, and the results, assuming every disagreement was a polygraph error, indicated an overall validity o f 98%. For deceptive cases the validity was also 98%, and for non-deeeptive cases, 97%. The studies were from police and private cases using a variety o f polygraph techniques conducted in the Unites States, Canada, Israel, Japan and Poland (Ansley, 1990, p.l71).
1.7 Cautions
However, while the polygraph technique is highly accurate, it is not infallible and errors do occur. Polygraph errors may be caused by a failure to properly prepare the examinee for the examination or by a misreading o f the physiological data on the polygraph charts. Adherence to established testing protocols and stringent polygraph training requirements are the best way to
control for these errors which are usually referred to as either ‘false positive’ or ‘false negative’. A ‘false positive’ error occurs when a truthful examinee is reported as being deceptive, a ‘false negative’ occurs when a deceptive examinee is reported as being truthful.
The American Polygraph Association has endorsed specific guidelines and procedures to identify the presence o f factors which may cause false responses, and to ensure an unbiased review o f the polygraph records. The polygraph examiner will ordinarily offer a finding of Deception Indicated (DI), No Deception Indicated (NDI) or No Opinion (NO) an inconclusive result which simply means that the polygraph examiner is unable to make a definite judgement. In this last eventuality, a second examination is usually conducted at a later date and in approximately 90% o f those cases, the examiner is able to render an opinion at that time.
A number o f protective procedures are now incorporated into polygraph testing through the increasingly rigorous guidance given by the American Polygraph Association (1997). Medical information about the subject’s physical condition is routinely obtained. Specialised tests are employed to identify the overly responsive examinee and to calm the overly nervous. Meaningful comparison questions are formulated to evaluate the examinees’ responses to a variety of relevant and irrelevant questions. An assessment is also made of emotional state. The pre-test interview is now given considerable attention to establish the appropriate ‘psychological set’, to review test questions and to establish whether any other extraneous variables are likely to adversely influence the results o f the examination. Quality control and peer reviews o f examination procedures and chart data have also improved polygraph practice and accuracy.
Matte (1996) noted that countermeasures can be employed to confound or misrepresent polygraph results. However, he also judged that properly trained
and experienced polygraphists can predict and control these factors, minimising the risk of this kind o f manipulation.