Keep up to date with Drugs & Crime

New research finds polygraphs effective for sex offenders

University of Kent polygraph
University of Kent research concludes that voluntary and mandatory polygraph testing increases the likelihood that individuals convicted or suspected of committing a sexual offence will reveal risk-relevant information.

Share This Post

Share on twitter
Share on facebook
Share on linkedin
Share on email

Polygraphs elicit more risk-relevant disclosures

New (18 March 2020) research from the University of Kent, commissioned by the National Police Chiefs Council concludes that voluntary and mandatory polygraph testing increases the likelihood that individuals convicted or suspected of committing a sexual offence will reveal risk-relevant information.

Research was carried out by Kent’s Centre of Research and Education in Forensic Psychology (CORE-FP) over a two-year period. Information was provided by police officers, including risk-relevant disclosures made by participants, the seriousness of disclosures, and actions taken in response.

The research

The researchers analysed polygraph tests in nine police areas focusing on three categories of sex offenders:

  • Strand 1 (Supervisees): 557 individuals convicted of sexual offending and undergoing police supervision who were randomly assigned to polygraph testing (voluntary or mandatory1 depending on police area) or comparison groups.
  • Strand 2 (Suspects): 142 individuals suspected of committing online sexual offences and undergoing police investigation who were assigned to polygraph or comparison groups.
  • Strand 3 (Applicants): 104 individuals convicted of sexual offending who applied for removal of notification requirements and were assigned to polygraph or comparison groups.

The research compare groups of individuals who were undergoing polygraph testing with comparison groups of individuals who were not and examined in particular the number of risk-relevant disclosures made by the three groups.


Strand 1: Supervisees

  • Voluntary or mandatory polygraphed supervisees were equally likely to make RRDs, but voluntary polygraph tests often failed to go ahead.
  • Relative to comparisons, supervisees undergoing polygraph testing (voluntary and mandatory) were nearly 6 times more likely to make at least one RRD.
  • Supervisees across all levels of risk were more likely to make a RRD than comparisons.
  • During polygraph sessions, polygraphed supervisees made more RRDs in the pre-polygraph interview than they did in the post-polygraph interview. Polygraph test results revealing a significant response (i.e., indicative of an untruthful response) were associated with higher levels of post-polygraph interview RRDs.
  • Offender managers in the polygraph group rated the helpfulness of the polygraph as over 5 on a 7-point scale; regardless of whether RRDs had been made. The qualitative statements made by Offender Managers in interviews supported this. However, they were concerned about the voluntary nature of the polygraph resulting in test refusal.

Strand 2: Suspects

  • Relative to comparisons, polygraphed suspects were over 7 times more likely to make at least one RRD.
  • Investigating officers rated polygraphed and comparison RRDs as equally relevant for investigative purposes.
  • Investigating officers rated the helpfulness of the polygraph as over 5 on a 7-point scale. However, their statements during interviews suggested some frustration about being unable to use the polygraph as evidence in investigations.

Strand 3: Applicants

  • Not one comparison applicant made an RRD, whilst nearly half of polygraph applicants made at least one RRD.
  • Applicants who underwent polygraph testing were 42.5 times more likely to make at least one RRD than were comparison applicants.
  • Comparison applicants were nearly 5 times more likely than those polygraphed to be successful in their applications for removal of notification requirements.
  • Police officers involved in processing removal applications rated the helpfulness of the polygraph as over 6 on a 7-point scale. The qualitative statements made by Offender Managers in their interviews supported this.


Professor Jane Wood, Chartered Forensic Psychologist and project lead said:

Our findings support the police use of polygraph testing, particularly mandatory polygraph testing, as a supportive tool for managing individuals convicted of sexual offences who live in the community. This is because polygraph testing elicits important new information related to risk that would ordinarily remain unknown.

National Police Chiefs’ Council’s Lead for the Management of Sexual and Violent Offenders, Chief Constable Michelle Skeer, said:

‘This research has found that polygraph testing leads to more disclosures from registered sex offenders and recommends the introduction of mandatory tests for convicted sex offenders as being the most effective method of monitoring them by police. We will give this research careful consideration alongside others in policing and the Home Office as the recommendation would require a change in the law.
Policing in the UK has some of the most advanced and effective tools in the world to manage registered sex offenders and every day officers effectively manage the risk posed to the public by such people. This will always be a complex area of work for police and we continue to look at innovative ways, tools and technologies to keep people safe.’

Share This Post

Share on twitter
Share on facebook
Share on linkedin
Share on email

Related posts

One Response

  1. It is worth pointing out that asking offenders or suspects (sex or otherwise) their thoughts (e.g. “Have you had any criminal thoughts, this week?”) is not only inadmissible in court but is an illogical question. If someone has a belief about something that you (the police) don’t agree with , not only is that not proof of a crime (having been committed) but it is also a discrimination, against that person (and of all humans), of the most extreme and profound kind. If that person receives sanction (punishment etc), for having a belief (i.e. an opinion about anything or something), then this is a contravention of the “UN Charter on Human Rights” and, actually, leads to the implication that humans should not exist. For a human to ask for humans to not exist is , of course, illogical, in the same way that suicide is irrational.

    Here comes the profound part : Why does this lead to the implication that humans should not exist?
    Here is the answer: No human can be stopped from thinking. That is, from having thoughts or an opinion when asked to give one. So expecting a human to not act like a human or to wish to have that person not to think or act like a human, is an impossible wish or requirement on that individual. The only way to stop a particular person (the interviewee) from having a thought is for them to not exist. That is, to be put to death. And because all humans think, then, this is an argument that all humans should be put to death.

    It is not surprising that the police are keen for this. Many of their actions, plans and processes are of this kind i.e. irrational, destructive and unhuman. That is, it is consistent with their previous behaviours – for example deaths in custody, on the streets, in their vans, etc. The whole premise of the idea of having police is based on confrontation, aggression and punishment. There is no room for forgiveness, compassion or in many cases logic, when society agrees to have a police force. The idea of a convicted criminal saying sorry and that being accepted, by the police, is so alien to the police that one could claim they are, indeed not acting human. The definition of a civilised society is one in which forgiveness is accepted. Because the police and the Courts do no accept apologies then one can claim society has not civilised itself beyond prehistoric times.

    Many people have irrational thoughts and thoughts that, if acted out, would lead to people being put at risk and sometimes serious risk of harm. For example thinking or having a dream about the arcade game you played last night, where you drove in the Monte Carlo rally but crashed, is an example of reckless driving and reckless behaviour which, ultimately, resulted in the deaths (in the game) of the drivers. This is all imagined, yet those advocates of lie detector tests, including the police and many, many, others, in the UK, would want that to be a reason to punish you in the real, non-imagined, world. Dreams are not conscious decisions either.

    Today, your probation officer will ask you about your dreams in the hope that you will talk about them. Therefore, society has, already, reached the stage of accepting that thoughts are not allowed despite this being an irrational course of action as I have described here.

    Allowing lie detector tests to take place is just another irrational step bringing society ever closer to self-annihilation. Self-annihilation is just another word for suicide. And we know suicide is irrational.

    Thus, the real motivation behind lie detector tests is malicious.

    Long has the time passed that Government decisions were made on the basis of morals. The recent laws on the permissibility of abortion, in the UK, and euthanasia in other countries is additional proof of this. The only correct action, for society, is to have a police force that does, indeed, gather the evidence, but to have religious clerics make the decision on whether to prosecute , to what extent, or even at all, depending on the amount of contrition and promise of reparation offered by that convicted person. Religious clerics would be the overseers of the Polices’ actions. Because the UK was once Christian I think the religious clerics should, on that basis, be Christian ones. Those of other belief’s would be treated as if they were Christians. That is, the decisions would be overseen by the Christian clerics. This is how one would describe a country as being a Christian one. And on that basis a country that had Muslim Clerics overseeing the police would be described as a Muslim country. And, indeed these countries already exist. It is their poverty that does not allow that system to work. The UK has no soul and devil-decisions like the implementation of legalised abortion and lie-detector tests (punishment for having thoughts) are decisions that only bring more suffering to more humans and brings society ever closer to self-annihilation.

Leave a Reply

Your email address will not be published.

Privacy Preference Center

keep informed

One email every day at noon