This review traces the UK polygraph research programme led by Professor Don Grubin at Newcastle University, drawing principally on Grubin D, ‘Polygraph Testing of Sex Offenders’, Polygraph, 2016, 45(2):97–116 — an open-access reprint of the 2016 Springer chapter — alongside the Ministry of Justice evaluation reports and related primary sources. Full references appear in the Sources list below.
Methodology note. The original voluntary-trial findings were published in Grubin (2010) in Sexual Abuse 22(3), which is paywalled. This review cites those findings as reported in Grubin (2016), a later open-access publication by the same author that summarises the 2010 results. Where a claim derives from that secondary reporting, the footnote identifies the source as Grubin (2016) and notes its reliance on the earlier paper.
TL;DR
- In the voluntary polygraph trial, 70% of polygraphed sex offenders made new disclosures relevant to treatment or supervision on their first test, compared with 14% in a non-polygraphed comparison group — a 14-fold odds ratio.[1]
- In the mandatory pilot evaluation, 76.5% of polygraphed offenders made at least one disclosure, compared with 51.2% in the comparison group, with polygraphed offenders making roughly twice as many total disclosures.[2]
- Compulsory polygraph testing was rolled out nationally for serious sex offenders in England and Wales in 2014.[3]
- Statutory polygraph conditions were extended to domestic-abuse perpetrators (Domestic Abuse Act 2021, s.76) and certain terrorism-related offenders (Counter-Terrorism and Sentencing Act 2021).[4]
- In counter-terrorism polygraph examinations (June 2021 – June 2023), disclosures of risk-related information were recorded in 72% of examinations; significant responses occurred in 35%.[5]
Timeline overview
The Offender Management Act 2007 (ss.28–30) provides the statutory power for polygraph licence conditions on sex offenders released on licence in England and Wales.[6]
The voluntary polygraph trial takes place across 10 probation areas, supervised by Professor Don Grubin at Newcastle University. Nearly 350 offenders are polygraphed, with a comparison group of approximately 180 non-polygraphed offenders.
Mandatory polygraph testing for adult sexual offenders commences in the East and West Midlands probation regions.[7]
Grubin publishes the voluntary trial results in Sexual Abuse 22(3).
Gannon and colleagues publish the Ministry of Justice evaluation of the mandatory pilot (MoJ Research Series 14/12).[8]
Gannon and colleagues publish a full peer-reviewed evaluation of the mandatory pilot in Sexual Abuse: A Journal of Research and Treatment 26(2):178–203.[9]
The Ministry of Justice announces national rollout of compulsory polygraph testing for serious sex offenders in England and Wales.[10]
Grubin publishes the open-access summary chapter in the Polygraph journal (45(2):97–116), synthesising findings from the programme to date.[11]
The Domestic Abuse Act 2021 (s.76) and Counter-Terrorism and Sentencing Act 2021 extend polygraph licence conditions to domestic-abuse perpetrators and certain terrorism-related offenders respectively.
Counter-terrorism polygraph examinations begin; 88 examinations are completed on 39 individuals in the first two years.[12]
The voluntary 10-area trial (2007–2010)
The voluntary polygraph trial, conducted under the supervision of Professor Don Grubin at Newcastle University, compared the supervision outcomes of nearly 350 polygraphed sex offenders with approximately 180 sex offenders from probation areas where polygraphy was not used.[13] The study design calculated the ratio of new disclosures at the first polygraph test to new information obtained in the six months before that test.
Key finding: disclosure rates
Probation officers reported that new disclosures relevant to treatment or supervision were made in 70% of first tests, compared with 14% of non-polygraphed offenders making similar types of disclosure in the preceding six months. The odds of a polygraphed offender making a relevant disclosure were 14 times greater than for a non-polygraphed offender.[14]
A related finding concerned probation officers’ perceptions of offender honesty. In the evaluation of the voluntary pilot, Gannon and colleagues reported that whilst 73% of interviewed probation officers believed the offenders they supervised were “open and honest” with them, this figure fell to only 25% among probation officers who supervised polygraphed offenders.[15] This suggested that polygraph testing exposed a significant gap between probation officers’ assessments of offender candour and the level of forthcomingness that testing could elicit.
The mandatory pilot evaluation (2009–2014)
Mandatory polygraph testing for adult sexual offenders began in April 2009 across the East and West Midlands probation regions.[16] This pilot was evaluated by a team led by Professor Theresa Gannon at the University of Kent, with findings published both as a Ministry of Justice research report in 2012 and a peer-reviewed journal article in 2014.
Ministry of Justice evaluation (2012)
The 2012 MoJ evaluation found that clinically significant disclosures (CSDs) were consistently higher in the polygraph group than in the comparison group. The majority of these CSDs were made within a polygraph session and related to changes in circumstance or risk.[17]
Peer-reviewed evaluation (2014)
The 2014 peer-reviewed publication provided more granular findings. Offender managers in the pilot polygraph group, compared with those in the comparison group, reported:
The majority of disclosures made by sexual offenders in the polygraph group were associated with the polygraph session itself, reinforcing the finding from the voluntary trial that the polygraph examination acts as a catalyst for disclosure.[20]
Risk and test outcomes
Approximately one third of offenders — most notably those assessed as higher in risk — failed their first test with a result of “Deception Indicated”.[21] This finding is notable because it suggests that polygraph testing may be particularly relevant for the supervision of higher-risk offenders, though it also raises questions about the interpretation and management consequences of Deception Indicated outcomes in post-conviction settings.
National rollout (2014)
On 27 May 2014, the Ministry of Justice announced that compulsory lie-detector tests would be used on serious sex offenders across England and Wales.[22] The rollout was enabled by the statutory powers in the Offender Management Act 2007 (ss.28–30), which permits polygraph conditions to be imposed on sex offenders released on licence.
Professor Grubin was quoted in the Ministry of Justice announcement: “Polygraph tests can be an important tool in the management of sex offenders and can enhance provisions already in place.”[23]
The national programme built upon the evidence generated by both the voluntary and mandatory pilots, representing a transition from research to operational policy. Grubin’s 2016 summary noted that mandatory testing of high-risk sex offenders on parole was introduced in 2014 “after a number of trials”.[24]
Statutory extensions (2021)
The evidence base established through the PCSOT research programme informed two further statutory extensions in 2021:
- The Domestic Abuse Act 2021 (s.76) extended polygraph licence conditions to certain domestic-abuse perpetrators released on licence in England and Wales.
- The Counter-Terrorism and Sentencing Act 2021 introduced polygraph licence conditions for certain terrorism-related offenders. These conditions came into force from 29 June 2021.[25]
These extensions represented a policy decision to apply polygraph testing beyond the sex-offender population in which it had originally been trialled, into domains where the research base is less developed.
Counter-terrorism polygraph: early findings
A process evaluation published by the Ministry of Justice in October 2023, conducted by Keeton, Gerasimov, and Pearce, provided the first published data on the operation of counter-terrorism polygraph examinations.[26]
| Measure | Figure |
|---|---|
| Individuals subject to polygraph licence condition | 46[27] |
| Individuals who completed at least one examination | 39 |
| Total examinations completed | 88 |
| Examinations yielding significant response | 31 (35%) |
| Examinations with risk-related disclosures | 63 (72%) |
| Individuals recalled (polygraph-related) | 3 (plus 1 recall linked to non-compliance)[28] |
The 72% disclosure rate observed in counter-terrorism polygraph examinations is broadly comparable to the disclosure rates observed in the PCSOT sex-offender trials (70% in the voluntary trial, 76.5% in the mandatory pilot), though the populations, offence types, and examination protocols differ and direct comparison should be treated with considerable caution.
Evidence gaps and outstanding questions
The Grubin research programme has generated a substantial body of evidence on the utility of polygraph testing as a disclosure-enhancing tool in post-conviction sex-offender supervision. However, a number of evidence gaps remain:
- Accuracy studies. The UK programme has focused primarily on clinical utility — whether polygraph testing increases disclosures relevant to supervision and risk management — rather than on diagnostic accuracy (the rate of correct classification of truthful and deceptive responses). Grubin (2016) discusses two forms of sex-history examination used in PCSOT but does not present UK-specific accuracy data.[29]
- Long-term outcomes. Published UK research has not yet assessed whether polygraph-elicited disclosures lead to measurable reductions in reoffending rates over the longer term. [VERIFY: whether any such long-term outcome studies have been published since the supplied sources]
- Counter-terrorism and domestic-abuse populations. The extension of polygraph conditions to these populations preceded the development of a comparable evidence base to that which informed the sex-offender rollout. The Keeton et al. (2023) evaluation is a process evaluation rather than an outcomes study.[30]
- Probation-officer perceptions. The finding that polygraph testing substantially altered probation officers’ views of offender honesty (from 73% believing offenders were open and honest, to 25% among those supervising polygraphed offenders) raises questions about prior baseline assumptions in supervision, though these have not been further investigated in published UK research.[31]
Glossary
- CSD
- Clinically Significant Disclosure. A disclosure made by an offender that is judged relevant to risk assessment, treatment, or supervision.
- PCSOT
- Post-Conviction Sex Offender Testing. The use of polygraph examinations as part of the supervision and treatment of convicted sex offenders following release into the community.
- HMPPS
- His Majesty’s Prison and Probation Service. The executive agency of the Ministry of Justice responsible for correctional services in England and Wales, including the administration of statutory polygraph testing.
- OMA 2007
- Offender Management Act 2007. The UK statute that provides, at sections 28–30, the legal power for polygraph licence conditions on sex offenders released on licence in England and Wales.
- DAA 2021
- Domestic Abuse Act 2021. UK legislation that, at section 76, extended polygraph licence conditions to certain domestic-abuse perpetrators released on licence.
- Deception Indicated (DI)
- A polygraph test outcome in which the examiner’s analysis of the physiological data indicates that the examinee’s responses to relevant questions are consistent with deception.
- Sex-history examination
- A type of polygraph examination used in PCSOT. Grubin (2016) describes two forms: one focusing on unreported victims of contact offences, and another focusing on sexually deviant behaviour more generally, including non-contact offences such as voyeurism or internet-related offending.
- Disclosure rate
- The proportion of offenders (or examinations) in which new information relevant to risk, supervision, or treatment is volunteered during or in connection with a polygraph session.
- Odds ratio
- A statistical measure comparing the likelihood of an event occurring in one group versus another. In the voluntary trial, the 14× odds ratio meant polygraphed offenders were 14 times more likely to make a relevant disclosure than non-polygraphed offenders.
- Significant response
- In the counter-terrorism polygraph context (Keeton et al., 2023), an examination result classified as showing a significant physiological response to relevant questions, analogous to a Deception Indicated outcome.
This post is a chronological research review. It summarises published findings from the sources listed below. It does not constitute professional advice or legal guidance, and should not be taken as endorsing or criticising any particular policy position. The statutory polygraph regime in England and Wales is administered by HMPPS under the Offender Management Act 2007 and related legislation; BPS has no role in that regime. Readers seeking further information should consult the original publications cited in the Sources list.
Sources
- Grubin D. Polygraph Testing of Sex Offenders. Polygraph. 2016;45(2):97–116. Open-access reprint of chapter in Treatment of Sex Offenders: Strengths and Weaknesses in Assessment and Intervention, Springer, 2016. DOI: 10.1007/978-3-319-25868-3_6. PDF: polygraph.org.
- Gannon TA, Wood JL, Pina A, Vasquez E, Fraser I. The evaluation of the mandatory polygraph pilot. Ministry of Justice Research Series 14/12. London: Ministry of Justice, July 2012. ISBN 978-1-84099-555-8. gov.uk.
- Gannon TA, Wood JL, Pina A, Tyler N, Barnoux MFL, Vasquez EA. An evaluation of mandatory polygraph testing for sexual offenders in the United Kingdom. Sexual Abuse: A Journal of Research and Treatment. 2014;26(2):178–203. DOI: 10.1177/1079063213486836. Kent Academic Repository.
- Keeton S, Gerasimov W, Pearce L. The use and operation of counter-terrorism polygraph examinations: Process evaluation findings. Ministry of Justice Analytical Series. London: Ministry of Justice, October 2023. ISBN 978-1-911691-17-4. assets.publishing.service.gov.uk.
- Ministry of Justice. Compulsory lie detector tests for serious sex offenders (news release). 27 May 2014. gov.uk.