A concise explanation of the Polygraph Test
Whether in the context of conversation, examination report, media contact or courtroom discussion it can be useful to have a well-constructed concise explanation of the polygraph test. A reasonably complete explanation will convey information about the theory of the test along with simple and usable information about psychological and physiological foundations of the test, in addition to information about the test data analysis and expected accuracy of the test. A highly useful explanation will quickly orient a reader or listener to the correct concepts and terminologies, will provide practical and convenient answers to common questions, and may help to deter occasional tendencies to engage in wishful thinking or naive expectations about polygraph testing. Fol- lowing is an example of an explanation of the polygraph test that may be useful to stimulate additional discourse:
Psychophysiological detection of deception (PDD) testing, also known as the polygraph test – sometimes referred to as “lie-detection” as a term of convenience – is a standardized, evidence-based test of the margin of uncertainty or level of confidence surrounding a categorical conclusion of truth-telling or deception. The analytic theory of the polygraph test is that greater changes in physiological activity are loaded at different types of test stimuli as a function of deception or truth-telling in response to relevant target stimuli. Adequately selected polygraph target issues will involve a behavioral act for which an examinee can know unequivocally whether one has engaged in that action.
A polygraph test consists of an of a pretest interview, test data acquisition, and test data analysis phases. Post-test procedures can include other ancillary activities, including additional discussion, testing and investigation. Completion of a polygraph test can take upwards of 90 minutes, and should take place in a controlled environment, so that an examinee can adequately attend to and concentrate on the test topic and test stimuli without distraction. In this way, changes in physiological activity, if they are timely and independent of other observable influence, can be reliably attributed to the test stimuli.
The psychological basis of responses to polygraph test stimuli can be thought of as involving a combination of factors including: attention, cognition, emotion, behavioral conditioning and other resources for self- control. Differences in deception and truth-telling can manifest in patterns of response that can become observable upon repeated iterations of relevant and comparison stimuli. Statistical classifiers can be calculated for observed changes in physiological activity.
Polygraph test data are a combination of physiological proxies that have been shown to correlate significantly with different types of test stimuli as a function of deception or truth telling in response to deception or truth-telling when answering relevant investigation target stimuli. Polygraph recording sensors include respiration activity, electrodermal activity, and cardiovascular sensors in addition to an optional vasomotor activity sensor. Polygraph recording sensors are autonomic – because activity in the autonomic nervous system has been shown to be correlated with differences between deception and truth-telling. Although each of the individual sensors is itself insufficient as a strong probabilistic indicator of deception or truth-telling, each of the different sensors contributes additional information to an optimized structural or statistical model. Standards of practice today require the use of activity recording sensors to help identify faking or countermeasures.
Suitability for polygraph testing re- quires that an individual is functioning reasonably within normal limits in terms of basic physiology, psychology, cognitive functioning or level of development, and language/communication skills. Probabilistic calculations may not apply in normal ways for individuals whose functional characteristics are outside normal limits, or those for whom the basic theory does not reasonably apply. Most persons who can work, drive, attend school, live in the community and function independently are suit- able for polygraph testing.
Analysis of polygraph test data, like other test data, can be accomplished manually or via automated computer algorithm. Test data analysis involves several processes including: feature extraction, numerical transformation and data reduction, use of a likelihood function to calculate a statistical val- ue, and the use of structured rules to parse a categorical test result from the numerical and statistical test data. Whereas manual polygraph test data analysis methods may continue to rely on visual processes, comput- er algorithms offer the advantage of automated reliability. Reliability of manually scored test results may be strengthened when they concur with the results of automated computer scoring algorithms.
Published information indicates that event-specific single-issue poly- graphs can provide point estimate accuracy rates that exceed .90, depending on the test format and other factors. Multiple-issue polygraphs are both statistically and psychologically more complex than single-issue tests, with mean accuracy rates having point estimates that can exceed .80 for some polygraph techniques. Probabilistic estimates for polygraph test results can be calculated for both groups of cases (i.e. the observed frequency of correct or incorrect out- comes with groups of exams), and for individual cases (i.e., what is the likelihood that the data for a particular examination is correct or incorrect). Like other scientific tests, polygraph test results can be thought of as either positive or negative. Understanding and making use of polygraph test results can be thought of as a process of understanding the likelihood or potential for true-positive and true- negative in addition to the potential for false-positive and false-negative outcomes.
Polygraph testing does not detect, or measure, lies or deception per se. Actual detection of lies or deception – with deterministic perfection – and would be immune to both human behavior and random variation. Because deception and truth are not manifest- ed as unique physical phenomena there is no physical or linear measurement for deception or truth. Scientific tests are used quantify phenomena of interest for which neither perfect deterministic observation nor direct physical measurement are possible. For this reason, all scientific test results are fundamentally probabilistic, and are not expected to be infallible. Scientific tests are expected to provide a reproducible quantification of the margin of uncertainty or level of confidence that can be attributed to a test result or conclusion.
This description is by no means the only description or final word on the matter of polygraph testing. It is neither the most complete and comprehensive description nor the most abbreviated description. It is an evolution of numerous other at- tempts to describe the polygraph test in report writing, courtrooms and other areas of discussion with professionals that may wish to understand or make use of polygraph test data or test results. This description starts with an assumption of a blank-slate level understanding, and attempts the lofty goal of quickly and efficiently integrating basic concepts from psychology physiology, decision theory and test theory. Other descriptions of the polygraph are possible, and may at times be more useful than this one. This description is offered with the hope that it may be useful in prompting discussion and stimulating additional advances in written and verbal communication among professionals who use polygraph tests.Read More
Home Lie Detector Test
Yes we do visit home addresses to conduct Lie Detector Tests however we always prefer an office address when possible as we can control more factors in an office, we have our own offices in Kent where we can offer an appointment at any time of day including weekends. For some people a home address is preferred and makes this whole process easier, especially for a client who suffers with anxiety. We need a distraction free environment in which to conduct a home Lie Detector Test and a table and chairs, although we do carry a portable table and chairs. We like the environment to be free from loud noises and distractions like children or pets running in whilst we are testing as this can affect a home Lie Detector Test.
We would always run a single issue test in a clients home to achieve maximum accuracy for the test and the client, this test comprises of three questions on a single issue, we work with the client to develop questions best suited for the test. We only test on fact, not in intent or on emotion, being a single issue test the questions are very similar and are repeated over multiple charts and an average result taken. The result is either a No Deception being a pass, or a Deception Indicated being a fail or in 4% of cases we can end up with an Inconclusive result which fortunately on a single issue test is very rare.
All Lie Detectors UK Examiners are fully qualified experienced American Polygraph Examiners, we always recommend you check the examiner out first, they should be listed on the APA website here
Get in touch and discuss your case with us in confidence and see if we can help, we have run thousands of tests in a home environment so can advise if yours is suitable. Appointments can be made at a time to suit you including evenings and weekends.Read More
Lie Detector Test – What happens on the day?
Twenty-four hours before the Lie Detector Test no illegal drugs or alcohol please, if you have any concerns over prescription medication please discuss this with the examiner, very few prescription drugs will actually cause an issue. We will always advise you of the full address and postcode and give you a contact number so you can plan your journey, if you are running late you can directly advise the examiner so he is aware. Do try to have something to eat on the day if possible.
On arrival we complete some paperwork, a consent form and ask you a few questions to ensure we can test you. Then we discuss what will be happening and conduct a pre-test interview discussing the issue at hand and if appropriate talk to your partner, usually asking you to wait in the waiting room. We then discuss questions together formulating three questions on a single issue based on fact, and ensure the questions are fair and that your happy with them, the questions are fully reviewed for total clarity and will be a straightforward yes or no answer only.
All tests are filmed to protect the examiner and yourself, the video isn’t released and is totally confidential. The examiner will discuss the data retention policy with you during the pre-test.
A number of polygraph tests will then be run including a practice test followed by a minimum of three real tests. The result that’s taken is an average of the three tests, same questions that have been practiced are repeated on each chart, usually in a different order. You will then be asked to wait in the waiting room whilst the examiner scores the charts which can take twenty minutes, if a second opinion is required you will be advised at this stage and the result will be given to you followed by a full printed report and email copy if requested.
And always make sure you examiner is a member of the American Polygraph Association.Read More
Inconclusive Lie Detector Test Results – What does it really mean?
So you have taken a Lie Detector Test and the results came back as Inconclusive, what does this result really mean and how often do we actually see it. Give me a pound for every time a client says ‘I bet my results are inconclusive, it’s just my luck’ I would be a rich man when working with clients!
In Lie Detector tests an inconclusive result is actually very rare, when using the latest equipment and the latest single issue techniques we have a four percent chance to see inconclusive results. When a result is inconclusive the examiner can run more charts to get a conclusive result but first he must look at other factors that could be causing Lie Detector inconclusive results in the first place. Some good examples are below.
Examiner Experience and Qualifications
You need to ensure the examiner is a member of the American Polygraph Association and in the UK the British Polygraph Association. This ensures they have been trained and have graduated a recognised course and will be using the latest techniques and equipment. An examiner who isn’t a member is very dangerous for the results, they have no regulation and won’t be following any set path. All UK Police and Government Examiners are members of the American Polygraph Association.
If the questions haven’t been formulated correctly and haven’t been fully discussed with the client first so they fully understand them this can cause an inconclusive lie detector results. I have seen reports from non-qualified examiners and it’s a serious concern as to the questions and techniques they use. An example is we would never test on ‘Do you love your partner?’ Because what really is love, another example would be ‘Do you intend to cheat on your partner?’ Im sure you will agree that intent changes by the hour.
If someone sitting a Lie Detector Test had a severe mental illness and didn’t disclose this in the pre-test it could cause an issue with a inconclusive Lie Detector results. We are not talking about anxiety or depression here by mental illness like schizophrenia. A good examiner will pick up issues like this.
If someone is guilty and attempts to cheat a Lie Detector Test and the Examiner isn’t experienced enough to pick this up, then it could affect the results. Fortunately, most things people do is usually very obvious to the trained examiner, as many as one in ten would potentially try and cheat a test to try to alter the results.
Either illegal or prescription medication can cause an inconclusive Lie Detector results. Again a qualified and experienced examiner would ask the right questions to ensure this shouldn’t happen unless the person has taken drugs to try to alter the results which we have seen happen a few times. Fortunately, its very rare and usually results in some very odd charts which has us questioning the results and possibly giving a Purposeful Non Co-Operation PNC result. I saw this recently when a client had drunk four strong coffees one after the other and had a resting heart rate of 130 beats per minute and was very jittery. They were honest in why and explained its normal for them to drink so much coffee in one go. I suspect it was because they didn’t want to be tested.
So you can see above some of the reasons we may see inconclusive results on a Lie Detector Test. To alleviate this please make sure you use a company that employs fully qualified and experienced examiners, ask the name of the examiner who will be testing you, make sure they are listed on the APA and BPA websites as current members, even Google their name. I only take a booking when I have spoken to the client first on the phone and ensured that a Lie Detector Test is right for them and explained the process to them.
Jason Hubble the author has been a Polygraph Examiner for over five years, he owns Lie Detectors UK.Read More
Lie Detector Results
When you’re taking a Lie Detector have you considered what the results may be and how they are delivered to each client?
The results can be one of three and depending on the type of test they are reported differently however the consumer is looking for either a Pass or a Fail when the Lie Detector results are given. The third result is not one we see very often, when using the latest techniques and equipment we have a four percent chance of seeing an Inconclusive result, this means the scores aren’t sufficient to either pass or fail someone. An inconclusive result does not mean the person has done what they have been accused of, however what it does mean is we are unable to clear them either.
A Polygraph Examiner may refer to the results as No Deception Indicated (NDI) which is a Pass, or Deception Indicated (DI) which is a Fail. Depending on the type of test you could also see No Significant Reaction (NSR) which is a Pass or Significant Reaction (SR) which is a Fail.
A single issue Polygraph test conducted by a qualified American Polygraph Association examiner using the latest equipment and techniques will achieve accuracy levels of between 92% and 95%. We prefer not to run multi issue tests as we lose a significant amount of accuracy, a multi issue test would comprise of three questions that are not linked to the same issue.
In most situations the Polygraph Examiner will deliver the results at the end of the test, usually after four Polygraph charts have been run. The Examiner will need sufficient time to analyse the results and draw an opinion. They will also provide a full written report with the results and should run through this with you. If a client does fail a Polygraph Test we like the chance to speak to them to try and find out why they are failing. However, during the pre-test, we ask lots of questions to ensure there is no reason a client would fail unless they are coming to lie on a Polygraph test which would show up in the results.
To get the most accurate results for your Lie Detector Test please make sure you use a fully qualified and experienced Polygraph Examiner, in the UK a list of Examiners can be found on the British Polygraph Associations Website, or click here to take you there. Always make sure you know the name of the Examiner and you have verified they are qualified before parting with any money.
Lie Detectors UK Examiners are all BPA and APA members and will be delivering the most accurate Lie Detector Results available today. Click here to make a booking.
Polygraph Tests And The Law
The truth, the whole truth and nothing but the truth: Polygraph tests and the law by Regan Peggs of Regan Peggs Solicitors
Are lie detector tests admissible in court
A question that often arises from clients is whether polygraph tests, commonly called ‘lie detector’ tests, can be used as admissible evidence in court or during other legal proceedings. So what exactly are polygraph tests, how reliable are they, and what does the law say about how they can be used?
What is a polygraph test?
A polygraph test, or lie detector test, can be used as a tool to assess the likelihood that an individual is lying, or being deliberately misleading, about a specific event or fact.
During a test, the subject is asked a series of questions whilst being monitored for changes in breathing patterns, heart rate and perspiration levels using a combination of sensors attached to the chest, arms and fingers. The resulting data is interpreted using a sophisticated algorithm that can predict the likelihood of the subject having answered the questions truthfully.
How reliable is a polygraph test?
Polygraph tests are around 80-95% reliable, depending on the type of test, the number of questions asked and various other factors.
People often ask whether it is possible to cheat on a lie detector test. While it is possible for an individual to consciously control their breathing and even their heart rate for a short time, it is extremely hard to maintain this control, and virtually impossible to prevent the tiny changes in perspiration that are produced as a result of the ‘fight or flight’ response of the nervous system.
While there are some medications that can affect measurements such as heart rate, these effects are generally accounted for during ‘pre-testing’ – the period before the test during which an examiner asks a series of neutral questions to provide a baseline response for the subject.
The exception to this is any psychoactive drug (including both cannabis and alcohol), the excessive use of which is likely to affect a subject to such an extent as to render the test results void.
However, not only are polygraph examiners are trained to spot the telltale signs of psychoactive drug use, but the levels of these substances that would be required to significantly skew the results of a polygraph test would mean that their effects would likely be obvious to even the most casual observer.
Polygraph tests as evidence in court Lie detector tests are not routinely used in courts in England and Wales. However, they can be used in some circumstances, depending on the type of court.
There are several different types of court, including criminal, civil and family courts, as well as employment and other tribunals. All of these are typically presided over by magistrates or judges (and/or juries), whose role it is to hear evidence from witnesses and submissions from advocates, to assess the credibility and arguments of all parties involved, and to issue a ruling based on their own interpretation of the law (and on their own personal judgement).
In civil courts and tribunals, polygraph tests are not used as evidence in their own right but can sometimes be used to add weight to the evidence of either party. In the criminal courts, lie detector tests are of little use as they are not allowed as evidence, supporting or otherwise.
Whatever the type of court (or tribunal), it is usually up to those presiding over the court on the day as to what types of evidence are allowed. So while polygraph tests can be a useful supplement to existing evidence, there is no guarantee that they will be accepted for use in any individual trial.
Other legal uses for polygraph tests
Aside from their use in court cases, lie detector tests can also be used as a tool in evaluating the potential for release of existing offenders from prison.
In the UK, polygraph tests are used by the National Offender Management Service to inform decisions about the early release and licensing conditions of convicted sex offenders. Individuals are tested every 3-6 months, and the results of the tests taken into consideration along with other evidence. The success or failure of a lie detector test does not guarantee a particular parole decision, and individuals have a right to appeal a licence revocation that has occurred as a result of evidence from a polygraph test.
A similar system has recently been proposed by the government for those convicted of domestic abuse, whereby offenders would be subject to polygraph testing as a condition of their licence following their release from custody.
In some other jurisdictions, more weight is given by parole boards to the results of lie detector tests. For example, in the US, polygraph tests are routinely performed on sex offenders who are due for release, the failure of which can result in additional time being added to the subject’s sentence.
Finally, the police in some countries use lie detector tests for investigative purposes, for example to rule out suspects from their inquiries, obtain a confession or to generate more lines of inquiry. While this does not currently happen in the UK, there are calls for this approach to be adopted here in future, including by Don Grubin, emeritus professor of forensic psychiatry at Newcastle University and renowned expert in polygraph testing.
“There is a real reluctance to use [polygraph testing] in investigations for reasons that I think are irrational,” Professor Grubin said, speaking to The Independent in 2015. “If it is used as part of a thought-through strategy it helps you to eliminate suspects and gain numerous other leads.”
Lie Detectors UK recommends Regan Peggs as a forward thinking Law Firm who lead the way in their industry.Read More
Lie Detector Test Machine
The Lie Detector Test Machine we use is commonly called a Polygraph, which stands for many writings, in the United Kingdom we know the Lie Detector Test Machine as a Lie Detector. The Lie Detector Machine was invented in the 1920s by John Larson and was an analog device, it continued to be improved and the computerized Lie Detector Machine were introduced in the 1992. Now all examiners will use a computerized machine to record the results more efficiently. Below is pictured a 1980s Analog device that Lie Detectors UK own but do not use. Its purely a prop in our offices.
A lot has changed in the industry due to the research that has gone into the techniques and validated methods that are used to polygraph someone today. Accuracy levels have risen greatly, now a single-issue lie detector test is 92% to 95% accurate. Most Governments now have polygraph programs, in the UK there are more Government employed examiners than there are private examiners. The UK Sex Offender Polygraph Program has put over 170 sex offenders who were on probation back behind bars it has been that successful.
There are four main brands of Lie Detector Test Machines available today and quite simply put they all do the same job, some excel in different areas. Lie Detectors UK use Stoelting CPS Pro polygraphs however Limestone, Lafayette and Axciton also make computerized Lie Detector Machines that are used by other qualified APA Examiners. Whilst it is not mandatory to use a computerized polygraph it’s something a consumer should be aware of and ask for, all qualified UK Examiners use the latest polygraph machines.
Lie Detectors UK comprises of three fully qualified Examiners who test UK wide and have their own offices at which they charge £399 for a lie detector test. They are all members of the APA and the BPA which denotes not only quality but experience. Call today and discuss your case with an examiner on 0207 859 4960. Or book online here.Read More
Wide Array of Uses for Lie Detector Test
As a private investigator, the lie detector is a superb aid to have. They have found over the year that a lot of clients need their partners tested perhaps this is because a lot of television shows utilise it. The public is more aware of it’s availability to each and everyone and not out of their reach and are aware the examiner needs to be a member of the American Polygraph Association to be qualified.
So you need to ask the question?
Is your partner or husband or wife cheating? Are there questions in your relationship which keep being unanswered? Once the trust is lost or if it is questioned in a relationship, it can take so many years to recover. In most cases, the proof of infidelity is not definitive.
The best and most reliable and accurate way to know the truth is using a lie detector test. This test has been utilised widely in relationship problems. This is one area of testing in which experience makes a huge difference. The wording of questions is essential to obtain a successful test; different people construe words differently. This format is utilised to know whether one partner has been sexually or intimately involved with someone other than her or his partner. Integrated with this format might be questions regarding dating, kissing, as well as physical contact with others.
What else can you test for?
The Lie Detector is used it for personal background checks. This specific format is suitable when a partner wants to bear out aspects of his or her partner’s background like drug or alcohol habits, sexual history, health issues, gambling particularly STDs as well as too many financial obligations.
There are ways for lie detector test that include online activities and not all cheating needs physical contact. They can test to know the level or degree of sexual activities done over the net, like a visit to porn sites, dating sites, or visit sexual webcam, chat room, interactive sexual websites or having cybersex with someone who isn’t his or her partner. The lie detector test can also be utilised each time the truth is required, for instance, sexual abuse issues, pre-employment screening, theft, drug abuse, family disputes, and many other cases.
Other types of testing take account of personal theft issues that can be utilised in cases wherein parents utilise his device as an investigative tool. This is used to help in knowing the truth when members of the family, kids or acquaintances have fallen under doubt to be involvement or knowledge in recent burglaries of personal property, embezzlement as well as vandalism.
Also, employment theft concerns a lot of employers uses the test as a tool to help in knowing whether or not workers had any knowledge or involvement in recent robberies, misappropriation of company funds or property.
So now you have all the information regarding testing, utilise it, it is not only for peace of mind in cheating partner cases. You just need to ensure you uses a reputable company who employ fully qualified examiners like Lie Detectors UK.Read More
Lie Detector Test
A polygraph machine or popularly known as lie detector is utilised to help in knowing if someone is truthfully answering a specific set of questions or he or she is lying. It is a combination of different devices utilised to measure the physical responses of a person to what is known as irrelevant, control as well as relevant questions. How the examiner interprets, this information will find out if the person being asked is telling a lie.
In a conventional lie detection test, the person is asked many questions before the actual test is done.
These are utilised make what is called as a baseline. How the personal reactions to the set of questions will help make the baseline. The blood pressure, pulse, rate of breathing as well as how much they sweat and blood flow can be all measured as physical reactions to help make the baseline. Once the actual test questions are asked the reply to these questions is compared to those questions asked to make the baseline.
There are three kinds of questions asked to the person. Some are irrelevant like asking the person what his or her name is. Others are called directed-lie or probable lie control questions and most of the time get a reply that is not truthful. This kind of question can be asking the person if he or she ever committed a crime.
The kind of question most significant to the examiner is what is known as a relevant question. A relevant question would be like asking the subject if they committed the crime. If the person responds to the probable-lie control question is more significant compared to the related issues, then the reply to the relevant question is well thought-out truthful.
It must be noted there are over 40 Government employees working with the lie detector in the UK, to date they have put 170 sex offenders back behind bars through the lie detector test program. Knowing how this useful machine works could help you understand how people reply to questions when it comes to telling the truth.
Lie detector indeed has lots of uses. It also provides lots of benefits. If the time comes that you need to know the reality or the truth, you can consider a lie detector test. Some companies offer lie detector services, make sure to find one that is both reputable and reliable as well. Lie Detectors UK are a leading Lie Detector Test company in the UK only using fully qualified American Polygraph Examiners who are also members of the British Polygraph Association. They charge £399 at their head office in Kent and £499 anywhere else in the country fixed pricing. Call today and discuss your case with an examiner.