Internet vs Contact Offenders Under UK PCSOT: An Evidence Gap

This research brief addresses a frequently asked question in UK post-conviction sex offender testing (PCSOT): whether polygraph disclosure patterns differ between online-only (internet-based) and contact sexual offenders. It draws on Grubin (2016), Gannon et al. (2012), and Keeton et al. (2023) — see Sources — and is explicit about what the published evidence does and does not show.

Why the Question Matters

The landscape of sexual offending has shifted markedly over the past two decades. Indecent-image and online-grooming offences now constitute a substantial proportion of the caseload managed by HMPPS under post-conviction polygraph licence conditions. Practitioners, offender managers, and treatment providers regularly ask whether the polygraph elicits different patterns of clinically significant disclosure from individuals convicted of internet-only offences compared with those convicted of contact offences.

The question has practical implications. If disclosure patterns do differ — in frequency, content type, or timing within the examination session — that information could inform treatment planning, risk-management resource allocation, and the design of examination protocols. Conversely, if no meaningful difference exists, the current unified approach to PCSOT scheduling and resourcing may be confirmed as appropriate.

How UK PCSOT Is Structured: Two Sex-History Formats

UK post-conviction sex offender testing already recognises, at the level of examination design, that internet-related and contact offending raise different concerns for the examinee. Grubin (2016) describes two forms of sex-history examination used in PCSOT.^[1]

The first format focuses on unreported victims of contact offences. The second focuses on sexually deviant behaviour more generally, including offences that do not involve force — such as voyeurism or internet-related offending.^[4] The rationale for separating the two is that the more severe potential consequences associated with contact-offence disclosures may contaminate responses to questions about the less severe category of behaviour.^[5]

What Broader UK Evaluations Tell Us

The most directly relevant UK evaluation is the mandatory polygraph pilot assessment conducted by Gannon et al. (2012). The pilot, which commenced in April 2009 across the East and West Midlands probation regions, found that clinically significant disclosures were consistently higher in the polygraph group than in a comparison group.^[2] The majority of these CSDs were made within a polygraph session and related to changes in circumstance or risk.^[6]

Critically, however, the published evaluation material does not break down CSD rates by the index offence subtype of the examinee — that is, it does not report separately for internet-only and contact offenders.^[7] The evaluation demonstrates that polygraph testing increases disclosure overall, but it does not tell us whether it does so equally across offender subgroups.

The Counter-Terrorism Polygraph and Internet Use

A more recent evaluation provides a suggestive — but not transferable — data point. Keeton et al. (2023), evaluating the counter-terrorism polygraph regime administered under the Counter-Terrorism and Sentencing Act 2021, found that risk-related information was shared in 79% of examinations (37 of 46 individuals examined between June 2021 and June 2023).^[3] Of those reports containing risk-related information, 86% involved unauthorised internet use.^[8] Contact with prohibited persons was recorded in 43% of such reports.^[9]

The Research Gap, Stated Plainly

To date, no published UK study has disaggregated polygraph disclosure patterns by online-only versus contact sexual offence classification. The two-format sex-history examination structure described by Grubin (2016) creates a natural framework for such an analysis, but aggregate disclosure data from the published pilot evaluation (Gannon et al. 2012) and subsequent reporting have not been presented in this way in the publicly available literature.

This means that commonly asked questions — such as whether internet-only offenders disclose at higher or lower rates than contact offenders, whether the content of their disclosures differs qualitatively, or whether one examination format is more productive than the other for a given subgroup — remain unanswered by published UK evidence.

What Practising Examiners Can Do Now

In the absence of UK-specific published data disaggregated by offence subtype, practising examiners should consider the following approaches, consistent with existing Standards of Practice:

• Adhere to the two-format sex-history structure. The rationale for separating contact-victim and deviant-behaviour examinations, as described by Grubin (2016), remains sound and serves to minimise contamination effects.^[5]
• Document disclosure types systematically. Recording whether disclosures pertain to internet-related behaviour, contact behaviour, or other categories — and linking these to the examinee’s index offence classification — creates the raw data that future research will need.
• Contribute anonymised data to future research. Practitioners working within HMPPS or alongside probation services are well placed to support structured data-collection initiatives, subject to data protection requirements and the permissions of their employing organisation.

Closing: An Invitation for Structured Data-Gathering

The question of whether internet-only and contact sexual offenders display different polygraph disclosure patterns under UK PCSOT is both practically important and empirically unanswered. The examination infrastructure already distinguishes between the two offence categories at the protocol level. What is now needed is a structured, ethically approved research effort to analyse disclosure data by offence subtype — ideally drawing on the substantial volume of examinations conducted since the mandatory polygraph regime was rolled out nationally.

The BPS Research and Standards Sub-Committee welcomes discussion from members and researchers interested in contributing to this area of work.

Glossary

PCSOT

Post-Conviction Sex Offender Testing. A structured programme of polygraph examinations administered to individuals convicted of sexual offences, typically as a condition of community supervision or licence, to support risk management and treatment compliance.

CSD

Clinically Significant Disclosure. Information revealed by an offender — often during or around a polygraph session — that is judged relevant to their risk assessment or treatment. Examples include previously unreported victims, breaches of licence conditions, or changes in circumstances that increase risk.

OMA

Offender Management Act 2007. The UK statute (specifically sections 28–30) that provides the legal basis for mandatory polygraph testing of sexual offenders on licence in England and Wales.

HMPPS

His Majesty’s Prison and Probation Service. The executive agency of the Ministry of Justice responsible for administering prisons and the probation service in England and Wales, including the statutory polygraph regime for sexual and terrorism offenders.

APA

American Polygraph Association. A US-based professional organisation that sets standards, publishes research, and certifies polygraph examiners. APA certification pertains to individual examiners rather than to national bodies.

Sex History Exam

A category of PCSOT polygraph examination in which questions focus on the examinee’s full sexual history, including offending behaviour not covered by the index conviction. In UK practice, two formats are used: one for unreported contact victims, and one for sexually deviant behaviour more broadly (including internet-related offending).

Internet Offender

In the context of sexual offending, an individual whose offences are exclusively internet-based — such as possession, distribution, or production of indecent images of children, or online grooming — without any known contact sexual offence.

UK GDPR

The United Kingdom General Data Protection Regulation. The UK’s post-Brexit data protection framework, retained from EU law, which governs the processing of personal data — including sensitive data gathered during polygraph examinations.

Sources

1. Grubin D. Polygraph Testing of Sex Offenders. Polygraph. 2016;45(2):97–116. Available at: polygraph.org.
2. Gannon TA, Wood JL, Pina A, Vasquez E, Fraser I. The evaluation of the mandatory polygraph pilot. MoJ Research Series 14/12. 2012. Available at: gov.uk.
3. Keeton S, Gerasimov W, Pearce L. The use and operation of counter-terrorism polygraph examinations: Process evaluation findings. Ministry of Justice Analytical Series. October 2023. Available at: assets.publishing.service.gov.uk.

This is a research brief published by the British Polygraph Society for informational purposes. It is not a clinical protocol, practice directive, or risk-assessment tool. Practitioners should refer to their employing organisation’s policies and to the relevant statutory framework — including the Offender Management Act 2007 (ss.28–30) — for operational guidance. The BPS is a UK membership body and does not administer the statutory polygraph regime.