FAQs (Frequently Asked Questions) about Lie Detector Tests

Sep 24, 2022 | Polygraph Examiner

In addition to queries relating to how the polygraph works we also get FAQs about lie detector tests and the actual questions that can be asked. Our polygraph examiners are highly experienced, internationally qualified professionals, having administered thousands of examinations globally. They conduct lie detector tests ethically in full compliance with international protocols and standards. There is never any deviation from upholding these standards which include the method in which tests are conducted, the amount of time taken for investigating and questioning; and the question and scoring formulation utilised to ask questions and analyse them. The test will usually take up to 2 hours depending on the complexity of the matter.

Pre-test consultation / interview

The pre-test consultation is an information gathering and sharing process between the examiner and the subject. The examiner explains to the subject what will happen during the test, how the polygraph works, goes through the questions to be proposed and ensures that the subject is relaxed.  Many people believe that being nervous will make them fail the test but this is not true. Details of the subject are taken for administration purposes and then if the subject is happy they will be required to sign a form consenting to the test.  If required this will also include an agreement that the test will be video recorded. FAQs about lie detector tests are also covered as well as any others that the subject may want answers to.

The polygraph test

After the pre-test consultation the examiner is ready to begin the test. Initially the subject will be familiarised with the polygraph instruments and the testing process. The examiner may ask the subject to lie during the calibration process. The software and instrument is then set to the subject’s criterion. To obtain the necessary scientific data for review and scoring, the examiner will run a minimum of 3 to 4 charts. The examiner uses a variety of software for scoring purposes to obtain results. After the test the subject will sign a confirmation, assuming they are satisfied, that the test was administered in the way they were told it would be and that the questions asked were understood.

Questions used:

Our examiners must utilise authentic, scientifically verified procedures to propose questions.  Lie detector tests that you may have seen on reality TV shows or in movies do not accurately portray polygraph testing in the real world. Modern polygraph techniques produce between 95 and 98 percent accurate results. If the examiner is unable to obtain an accurate score on any or all of the questions, the test will be marked partially or entirely “inconclusive” (no opinion). This will only occur if no clear result can be conclusively attained based on data acquired from the subject’s physiological changes in response to questions.

How many questions can be asked?

For accuracy the examiner will repeat a series of questions during the test a minimum of 3 times to ensure consistency. When seeking “yes” or “no” responses no more than 3 questions can be asked of the subject.  Changes or modifications to the precise wording of questions may possibly be made by the examiner to ensure they are defined and specific. Depending on the complexity of the case under investigation the examiner may wish to add a further question relative to the other 3.  This may be for expansion or confirmation of a result. The additional question will be at the sole discretion of the examiner if it is felt more evidence may be acquired.  However, the norm is that only 3 questions are asked. Test results will be supplied after the examiner has had time to fully analyse them and compile a report. The report is ordinarily prepared and sent to clients within 24-48 hours. The analysis is always verified by another accredited and qualified polygraph examiner. The result given in the report is final. Bribery and threats will not influence an examiner to in any way modify the results obtained from the test.  If the client wishes to arrange another test, such booking must be made online or by directly calling our head office.  The examiner will not be able to book an appointment direct. At the time of booking clients are requested to complete our pre-test information form and to provide as much detail about the case as possible. This includes the questions they want answers too, any facts they already have about the case with times and dates if appropriate. The more information provided, the more accurate the test results will be.

Questions that can be proposed:

All questions proposed must elicit “yes” or “no” answers.
  • Connective words (conjunctions) such as “or”, “and” etc. cannot be used since they make questions obscure and multi-sided. This leads to inconclusive results.
  • Drawn out, lengthy questions are not recommended. The fewer words used to construct them, the better.
  • The more questions related to the same matter, the more authentic the results will be. The examiner will suggest a range of different ways to rephrase questions so that they encompass every facet.
  • All questions must evolve around facts that are known, not opinions.
  • Questions must be constructed on one matter at a time. Multiple issues cannot be covered because the answer to part of the question could be true and other parts false, leading to obscure and inaccurate results.
  • Our examiners are specially trained in wording questions correctly so you can rely on their expertise.

FAQs about lie detector tests related to Infidelity

In matters of infidelity you can’t ask if the subject loves someone. The reason for this is because there are many different types and degrees of love. Any answer to this question would effectively be an opinion. Asking the subject if they will ever do something again or if they will do something in the future is not permitted.  The polygraph is not a crystal ball and nor is the subject.  For example, the subject may not at the time of the test intend to cheat on a partner but the next day could easily have a change of heart. Raising things that may have been said or done during an argument is not a good idea. This especially applies if the person was under the influence of alcohol or drugs.  They invariably can’t remember exactly what was said or done in such circumstances. The accuracy of the test can be affected when a person simply cannot remember. Questions related to sexual contact can be proposed. However, the examiner may rephrase them to avoid embarrassing or startling the subject. If an issue is complex or acute, the subject will benefit from a written precis of all facts and detailed information that exists. The examiner can then pose statement based questions to verify the subject’s honesty or lack thereof.


When dealing with theft, up to 4 questions can be asked although ordinarily 3 are sufficient. Below are example questions that may be posed to someone suspected of stealing.
  • Do you know who stole ‘X’?
  • Did you steal ‘X’?
  • Do you know where the missing ‘X’ is?
  • Did you intend to steal ‘X’?
  • Did you benefit from stealing ‘X’?
  • Before the theft of ‘X’ occurred did you know it would happen on ‘X’ day?

False accusations

A person who has been falsely accused of something may take a lie detector to prove their innocence.   Statement verification is the most efficient method for this type of test. Normally there is a mountain of background information leading up to false accusations. The polygraph examiner will benefit greatly from receiving a summary of events in order to formulate the appropriate statements that need to be verified.  Statement verification requires “yes” or “no” responses. Questions may be asked along the following lines:
  • Did you do ‘X’ as Mrs A stated?
  • When you denied being involved in ‘X’ were you lying?

Drug abuse:

If a subject is suspected of drug abuse, it is recommended that the individual has blood tests taken by a qualified medical professional so that the results are available.
  • All questions posed will elicit “yes” or “no” responses, for example:
  • Apart from the drugs mentioned, have you used any other illicit drugs in the past ‘X’ months?

FAQs about lie detector tests related to Domestic abuse

Polygraph examinations conducted to establish domestic abuse are usually emotionally charged and need to be handled with sensitivity. Statement verification is the most appropriate way of establishing the truth. Questions must be unambiguous and precise:
  • Did you hit ‘X’ on the face with your hand?
  • Did you use your hands on ‘X’ without permission so as to cause harm?
  • Did you use swear words/expletives when rowing with you wife as she alleges?
If the above FAQs about lie detector tests haven’t answered something you would like to know please call us on 0800 861 1058 or visit our full FAQ section at liedetectortest.uk/faq We are happy to share our experience and advice for free.
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