Many people assume that every request for a polygraph examination should proceed. If someone is willing to pay, and someone is willing to be tested, what reason could there be to refuse?
In practice, experienced examiners frequently conclude that an examination is not appropriate. The decision to decline a case is not a failure. It is often the most ethical, the most professionally responsible, and the most protective outcome for everyone involved.
One of the clearest indicators of a professional examiner is not the number of examinations they conduct. It is the willingness to decline inappropriate instructions.
Polygraph Examinations Are Not Suitable for Every Case
A professionally conducted polygraph examination is a structured, transparent process. It is not a casual exercise, and it is not appropriate in all circumstances. For an examination to produce meaningful, defensible results, a number of conditions must be met:
- Informed consent — the examinee must understand the process, its capabilities and its limitations before agreeing to participate.
- Clearly defined issues — the matters to be examined must be specific, factual and capable of being formulated into properly constructed test questions.
- Psychological suitability — the examinee must be in a physical and psychological condition that permits a valid examination.
- Voluntary participation — the examinee must participate willingly, without coercion, threats or undue pressure from any source.
- Realistic expectations — all parties must understand what a polygraph examination can and cannot achieve.
- Adequate preparation — sufficient time must be allowed for the pre-examination screening, question formulation and pre-test interview.
These are not administrative formalities. They are the conditions that protect the examinee from harm, protect the requesting party from reliance on unreliable data, and protect the integrity of the examination itself.
When an Examination Should Be Declined
There are circumstances in which proceeding with an examination would be professionally irresponsible, ethically indefensible, or potentially harmful. Recognising these situations requires experience, professional judgement and a willingness to place ethical obligations above commercial considerations.
An examination should be declined when:
- Coercion is present — a partner, family member or employer is pressuring someone to undergo testing against their will. Participation must be genuinely voluntary.
- Threats or intimidation are involved — if the examinee has been threatened with consequences for refusing the examination, or for producing a particular result, the conditions for a valid examination do not exist.
- Criminal organisations seek to identify informants — examiners have a duty to refuse instructions where there is reason to believe the examination is intended to facilitate serious criminal activity.
- The examination is connected to violence or organised crime — where circumstances suggest that the results may be used to justify or facilitate harm to an individual.
- The examination is intended to justify abuse or control — particularly in domestic contexts where one partner seeks to use the examination as a tool of coercive control rather than as a genuine attempt to resolve a factual question.
- The purpose is to manipulate legal proceedings — where the requesting party seeks a result that can be selectively disclosed or misrepresented.
- The examination is designed to obtain a predetermined outcome — any request that explicitly or implicitly expects the examiner to confirm a particular conclusion is fundamentally incompatible with professional practice.
- Significant mental or physical health factors affect suitability — conditions that may compromise the validity of the physiological data or place the examinee at risk must be identified and taken seriously.
- Appropriate relevant questions cannot be formulated — if the issues cannot be expressed as specific, behaviourally defined, testable questions, the examination cannot proceed on a sound scientific basis.
In each of these circumstances, the examiner has an independent professional duty to refuse the instruction. This duty exists regardless of the source of the instruction, regardless of the fee involved, and regardless of any pressure to proceed.
Safeguarding Comes Before Commercial Interests
Declining unsuitable work is not a sign of timidity or excessive caution. It is a defining feature of professional practice. An examiner who accepts every instruction without question is not demonstrating expertise. They are demonstrating a lack of professional judgement.
Safeguarding responsibilities apply in every case, but they are particularly acute when the circumstances involve:
- Vulnerable adults — individuals with learning disabilities, cognitive impairments, mental health conditions or other vulnerabilities that may affect their capacity to provide informed consent or to withstand the demands of the examination process.
- Domestic abuse — where there is evidence or reasonable suspicion that one party is using the examination as an instrument of control, punishment or intimidation.
- Coercive control — patterns of controlling behaviour may not always be immediately apparent. A professional examiner must remain alert to indicators that participation is not truly voluntary.
- Emotional manipulation — situations in which the requesting party seeks to use the examination process itself — regardless of the outcome — to humiliate, demean or exert power over the examinee.
- Exploitation — any circumstances in which the examination may be used to exploit a power imbalance between the parties.
Proceeding with an examination in the presence of safeguarding concerns does not reduce harm. It increases it. The examination lends a veneer of scientific authority to a process that, in those circumstances, lacks the conditions necessary for validity. The professional examiner’s first obligation is to ensure that no examination causes more harm than it prevents.
The Importance of Voluntary Participation
Informed, voluntary consent is not merely a procedural requirement. It is a precondition for a valid examination. Without genuine voluntary participation, the physiological data collected during the examination may reflect anxiety about the testing situation itself, rather than responses to the specific questions being asked.
Before any examination proceeds, the examinee should:
- Understand the examination process, including what will happen at each stage.
- Understand the limitations of polygraph testing — what it can and cannot determine.
- Have a genuine opportunity to ask questions and receive honest, complete answers.
- Participate voluntarily, without threats, inducements or pressure from any source.
- Understand how the results will be used, who will receive them, and what decisions may follow.
An examinee who has been coerced into attending, who is frightened of the consequences of refusing, or who does not understand the process cannot provide valid consent. Proceeding under these conditions compromises both the fairness of the process and the reliability of the results.
Professional Independence
A professional polygraph examiner does not work for the accuser. They do not work for the examinee. They do not work for the solicitor, the insurer, the employer or the family member who made the referral.
The examiner’s responsibility is to conduct a fair, impartial and professionally defensible examination — and to decline to do so when the conditions for a valid examination are not met.
This independence is not a luxury. It is the foundation of credibility. An examiner whose conclusions can be predicted by knowing who is paying for the examination is not a professional. An examiner who adjusts their methodology, their questions or their interpretation to satisfy the expectations of the instructing party has abandoned the principles that give the examination its value.
Professional independence means:
- Formulating questions based on the evidence and the issues, not on the preferences of the requesting party.
- Reporting results honestly, even when the outcome is unwelcome.
- Refusing to disclose selective or misleading summaries of findings.
- Declining instructions that compromise impartiality or scientific rigour.
- Maintaining the same professional standards regardless of the source of the instruction.
Why Proper Question Formulation Can Prevent Inappropriate Examinations
Many unsuitable requests become apparent during question formulation. When a requesting party is asked to define precisely what factual behaviour they want examined, it frequently becomes clear that the underlying concern cannot be expressed as a testable question.
Examples of questions that cannot be properly examined include:
“Do you love your wife?”
“Will you cheat again?”
“Are you a good father?”
“Do you intend to tell me everything in the future?”
These questions fail because they concern emotions, predictions, subjective judgements or future intentions — none of which can be assessed through physiological measurement. A polygraph examination assesses responses to questions about specific past behaviour. It does not measure character, predict the future, or evaluate the quality of a relationship.
By contrast, a properly formulated question might ask:
“Since January 2025, have you knowingly had sexual contact with anyone other than your partner?”
This question is behaviourally specific, time-bounded, unambiguous and concerns conduct that can be truthfully confirmed or denied. The discipline of proper question formulation serves as an effective filter: if the issues cannot be expressed in this form, the examination should not proceed.
The Value of the Pre-Test Interview
Suitability is assessed before any sensors are attached. The pre-test interview is the phase during which an experienced examiner evaluates whether the conditions for a valid examination are met.
During the pre-test interview, the examiner will:
- Review the case in sufficient detail to understand the context and the issues.
- Clarify the expectations of the requesting party and the examinee.
- Identify any safeguarding concerns, including signs of coercion, vulnerability or domestic abuse.
- Assess whether the examinee is participating voluntarily and with informed consent.
- Determine whether the issues can be formulated into appropriate, testable questions.
- Explain the limitations of the examination clearly and honestly.
It is entirely appropriate — and it is not uncommon — for an examination to be declined following the pre-test interview. The examiner may identify concerns that were not apparent from the initial referral. The examinee may disclose information that changes the nature of the issues. The questions may prove to be unsuitable on closer analysis.
Declining at this stage is not a waste of time. It is a demonstration that the process is working as it should.
Situations Where Alternative Services May Be More Appropriate
A polygraph examination is one investigative tool among several. It is not always the most appropriate tool, and it is never the only tool available.
Depending on the circumstances, a client may benefit more from:
- Statement analysis — evaluating the structure, consistency and linguistic features of a written or verbal account.
- Cyber psychology consultation — understanding digital behaviour, online relationships, or the psychological dynamics of technology-mediated communication.
- Legal advice — consultation with a solicitor where the issues involve legal rights, obligations or proceedings.
- Counselling or relationship therapy — where the primary need is emotional support, relationship repair or therapeutic intervention rather than factual investigation.
- Digital evidence review — professional analysis of electronic devices, communications or online activity.
- Further investigative enquiries — gathering additional information before determining whether a polygraph examination is warranted.
Recommending an alternative approach when a polygraph examination is not appropriate is not a failure to provide a service. It is the provision of a better service — one that prioritises the client’s genuine interests over revenue.
Ethical Standards
Professional polygraph practice is governed by ethical principles that exist to protect examinees, maintain the credibility of the profession, and ensure that examination results are scientifically defensible.
The principles that should underpin every examination include:
- Impartiality — the examiner must approach every case without prejudgement, regardless of who made the referral or what outcome is expected.
- Confidentiality — information obtained during the examination process must be handled in accordance with data protection legislation and professional obligations.
- Competence — the examiner must possess the training, experience and professional knowledge necessary to conduct the examination to an appropriate standard.
- Transparency — every aspect of the process must be explained clearly to the examinee, including the questions, the methodology and the limitations.
- Informed consent — participation must be genuinely voluntary and based on a clear understanding of the process.
- Procedural fairness — the examination must be conducted in a manner that is fair to all parties and that does not disadvantage the examinee.
These principles are not aspirational ideals. They are the minimum requirements of competent, ethical practice. An examination that proceeds without meeting these standards is not merely suboptimal — it is indefensible.
Frequently Asked Questions
Can a polygraph examiner refuse a case?
Yes. A professional examiner has both the right and the duty to decline any instruction where the conditions for a valid, ethical examination are not met. This is a fundamental aspect of professional independence.
Why would an examiner decline an examination?
Common reasons include coercion, safeguarding concerns, unsuitable questions, significant health factors affecting suitability, lack of informed consent, or circumstances suggesting that the examination may facilitate harm rather than reduce it.
Can someone be forced to take a polygraph?
No. In the United Kingdom, polygraph examinations in the private sector are voluntary. No individual can be lawfully compelled to undergo a private polygraph examination. The only exceptions involve certain statutory provisions for offender management under probation supervision.
Can my partner insist that I have a test?
No. Your partner can request that you consider an examination, but participation must be voluntary. An examiner who proceeds when the examinee is clearly unwilling or has been coerced is acting outside professional standards.
Can an employer require a private polygraph?
In the United Kingdom, employers cannot compel employees to undergo private polygraph examinations. Any examination in an employment context must be voluntary. The implications of refusal should be discussed with a solicitor if there are concerns about employment consequences.
Can a solicitor request an examination?
Yes. Solicitors may instruct a polygraph examination as part of case preparation. However, the examiner retains independent professional judgement and may decline the instruction if the examination is unsuitable. The examiner does not become an advocate for the instructing solicitor’s client.
Can an examination proceed if the questions are unclear?
No. If the issues cannot be formulated into clear, specific, behaviourally defined questions, the examination should not proceed. Ambiguous or poorly defined questions produce unreliable data that serves no legitimate purpose.
Does declining a case mean someone is being deceptive?
No. A decision to decline an examination is based on professional and ethical considerations — not on any judgement about the truthfulness of either party. Declining protects the integrity of the process, not a particular outcome.
What happens if the examination is unsuitable?
The examiner will explain the reasons for the decision, discuss any alternative approaches that may be appropriate, and, where relevant, recommend other services such as statement analysis, cyber psychology consultation, or legal advice.
What alternatives are available?
Depending on the circumstances, alternatives may include statement analysis, cyber psychology assessment, digital evidence review, counselling, mediation, or further investigative enquiries. The appropriate approach depends on the specific issues and the needs of the parties involved.
Conclusion
The most ethical polygraph examination is sometimes the one that never takes place.
This is not a paradox. It is a statement of professional principle. An examiner who is willing to decline inappropriate instructions — who places safeguarding, fairness and scientific defensibility above commercial considerations — is demonstrating the independence and integrity that give the examination process its credibility.
Every case referred to The Centre for Forensic Neuroscience is assessed individually. If the conditions for a valid, ethical and scientifically defensible examination are met, the examination will proceed with the thoroughness and transparency that the process requires. If those conditions are not met, we will explain why, discuss alternatives, and ensure that no examination causes more harm than it prevents.
If you are considering a polygraph examination and would like to discuss whether it is appropriate for your particular circumstances, we invite you to arrange a confidential consultation.
Dr Keith Ashcroft is an investigative psychologist and the director of The Centre for Forensic Neuroscience. He provides integrated behavioural assessment, credibility assessment and polygraph examination services for private, legal and corporate clients throughout the United Kingdom.
References
American Polygraph Association. (2023). Standards of practice. American Polygraph Association.
National Research Council. (2003). The polygraph and lie detection. The National Academies Press.
British Psychological Society. (2021). Code of ethics and conduct. British Psychological Society.
Grubin, D. (2010). The polygraph and forensic psychiatry. The Journal of the American Academy of Psychiatry and the Law, 38(4), 446–451.
Meijer, E. H., & Verschuere, B. (2010). The polygraph and the detection of deception. Journal of Forensic Psychology Practice, 10(4), 325–338.