Frequently Asked Questions

Most polygraph examiners, especially those who are members of professional associations, know that there is no future in unethical behaviour and will not jeopardise their careers by providing false results to suit a specific person.

The professional polygraph examiner will allow other polygraph professionals access to the recorded data to render second opinions.

It provides a certain assurance that no manipulation of the results happened.

The computer is used to record the physiological responses displayed by a subject during the examination.

Bespoke software, developed by the manufacturers of the equipment, governs the process.

This software does not allow the recorded data to be altered or manipulated in any way by the polygraph examiner.

The software prohibits the polygraph examiner to access the recorded data at all.

The pure recorded data is the only information that can be used by an examiner to substantiate his opinion.

The polygraph result constitutes the opinion of the polygraph examiner based on the procedure that he or she has performed. (Similar to the diagnosis of a doctor based on his examination.)

The opinion does not necessarily constitute proof. Proof, as required by a court of law, has to satisfy certain criteria.

A mere opinion does not meet these criteria. The polygraph result was never intended to provide proof.

The adage applies: To know is not to prove! It provides a very solid indication to assist with the continued investigation.

Unless the examinee is so nervous that he or she cannot sit still, nervousness does not affect the polygraph result.

As a matter of fact, all polygraph subjects are expected to be nervous.

As the ‘resting’ levels of the person are not known, the prevailing levels of nervous tension present the baseline and only responses deviating from this baseline are considered.

Don’t trust websites or persons offering “relevant” advice. Your efforts to try and manipulate a polygraph examination is likely to be noticed by the examiner (who is highly trained and experienced). Not only will you look stupid, but concerns will surface as to why you are trying to manipulate the outcome.

•request a second examination

•retain an independent examiner for a second opinion


False positives, False negatives: While the polygraph technique is highly accurate, it is not infallible and errors do occur – as is the case with any test. Polygraph errors may be caused by the examiner’s failure to properly prepare the examinee for the examination, or by a misreading of the physiological data on the polygraph charts. As with any test involving humans, it’s possible for an examiner to do everything correctly and still have the test result in an error. Errors are usually referred to as either false positives or false negatives. A false positive occurs when a truthful examinee is reported as being deceptive; a false negative, when a deceptive examinee is reported as truthful. Since it is recognized that any error is damaging, examiners utilize a variety of procedures to identify the presence of factors which may cause errors or an unbiased review of the polygraph records.


We can hand however you a coin if you insist. Choose “heads” for lying and “tails” for truth (or vice versa) and ask a relevant question to the suspect/examinee. Now flip the coin – it will produce approximately the same level of accuracy.


  • Members of the American Polygraph Association.
  • Trained in the USA 
  • Affiliated with various State and Regional Polygraph Associations And Federations
  • Post-Conviction Sex Offender Testing (PCSOT) certified

When a client chooses an examiner, it is extremely important to ensure that the individual is fully qualified from an accredited and recognized polygraph school and is a member of an international Polygraph Regulating Body – ie The American Polygraph Association or at least a State or Regional Polygraph Association/Federation.


Every effort is made to ensure the privacy and security of an examinee or client’s information. All files are restricted to those immediately involved in the procedure. The results of an examination or even the fact that an examination was conducted is carefully guarded information. Only the individual sponsoring the examination (and others as may be required by due process of law) is entitled to the facts concerning the results.


The polygraph helps to provide information regarding the integrity of workers quickly and accurately.

It can therefore be of great value in the appointment of personnel, as well as in establishing culpability in cases of employee theft or fraud. The polygraph is an invaluable aid in any personnel integrity maintenance program.


It often happens that individuals are unfortunately or unjustly implicated in a crime or marked as targets for accusations or inferences. In many cases, there is no way in which those concerned can restore the trust or protect their reputation from the harm of careless accusations. The polygraph examination provides an excellent opportunity to restore the trust between employee and employer and creates an unequaled opportunity for such individuals to substantiate their truthfulness and prove their innocence.


  • religious beliefs or affiliations
  • beliefs or opinions regarding racial matters
  • political beliefs or affiliations
  • beliefs, affiliations or lawful activities regarding unions or labor organizations
  • sexual preferences or activities


The polygraph technique allows for the level of a person’s general nervous tension. Most individuals will be nervous before and during a polygraph examination. However, this only affects the level from which recordings are made and does not affect the result of the examination, i.e. although the level of nervousness will affect the individual’s physiological baseline, it will not affect the variations on the baseline and consequently the result of the examination.


Unless contracted as such, no person can be compelled to undergo a polygraph examination.


During the past 75 years, over 250 different scientific studies have been conducted in this regard. The preponderance of available information indicates the polygraph technique to be reliable in as much as 85% to 98% of event-specific investigations. This proves the polygraph to be more reliable than most, if not all other conventional methods of investigation.


The American Polygraph Association (APA) believes that scientific evidence supports the validity of polygraph examinations that are conducted and interpreted in compliance with documented and validated procedure. Thus, such examinations have great probative value and utility for a range of uses, including criminal investigations, offender management, and selection of applicants for positions requiring public trust.  The APA Standards of Practice set some of the highest professional requirements for its members to ensure their polygraph services are valuable, reliable, and promote ethically responsible practices.  The APA also produces a variety of model policies that represent the current understanding of best practices, and makes them widely available so that polygraph examiners (both APA members and non-members) and their clients can be aware of what constitutes a valid examination process.  The APA believes that well informed departments, agencies, and clients will insist on APA members for their polygraph services.

Recently the APA undertook an exhaustive review of all of the peer-reviewed publications on polygraph testing that represented field practices and which met the requirements of the APA Standards of Practice.  A meta-analysis was conducted, and a report was completed in late 2011.  An executive summary of the report is freely available to the public through this website. Please visit  the Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques page to download the report.

The executive summary reports that 38 studies satisfied the qualitative and quantitative requirements for inclusion in the meta-analysis. These studies involved 32 different samples, and described the results of 45 different experiments and surveys. They included 295 scorers who provided 11,737 scored results of 3,723 examinations, including 6,109 scores of 2,015 confirmed deceptive examinations, 5,628 scores of 1,708 confirmed truthful exams. Some of the cases were scored by multiple scorers and using multiple scoring methods.   The data showed that techniques intended for event-specific (single issue) diagnostic testing produced an aggregated decision accuracy of 89% (confidence interval of 83% – 95%), with an estimated inconclusive rate of 11%.  Polygraph techniques in which multiple issues were encompassed by the relevant questions produced an aggregated decision accuracy of 85% (confidence interval 77% – 93%) with an inconclusive rate of 13%. The combination of all validated PDD techniques, excluding outlier results, produced a decision accuracy of 87% (confidence interval 80% – 94%) with an inconclusive rate of 13%. These findings were consistent with those of the National Research Council’s (2003) conclusions regarding polygraph accuracy, and provide additional support for the validity of polygraph testing when conducted in accordance with APA Standards of Practice.

 Several research studies conducted over the past forty years has shown that the polygraph result is accurate, provided that:

• the polygraph examiner is well trained and experienced;

• valid, internationally recognised protocols are applied;

• the examinees are suitable candidates to be examined (no serious medical issues prevalent, no drugs or substances have been taken to influence the results, and that they are sufficiently in contact with reality)

• the environment in which the examination takes place is conducive for polygraph examinations (no visual or audio distractions, temperatures controlled, etc.)

First and foremost: utmost proffesionalism.

A typical polygraph examination will include a period referred to as a:

  • pre-test interview,
  • a chart collection phase and a
  • test data analysis phase

During the pre-test, the polygraph examiner will complete required paperwork and talk with the examinee about the test, answering any questions the examinee might have. It is during this phase that the examiner will in detail discuss the test questions and familiarize the examinee with the testing procedure. The questions that are asked are discussed before the actual testing begins and it is during this phase that the examiner will make sure that the examinee fully understands all questions.

During the chart collection phase the examiner will administer and collect a number of polygraph charts. The number of questions and the number of charts will vary, depending on the number of issues and technique employed.

Following this, the examiner will analyze the charts and render an opinion as to the truthfulness of the examinee.

The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions presented during the test.

• It is a process to confirm or reject critical elements of information, typically to confirm that a person is truthful regarding specific issues.

• It is not an interrogation.

• It is always voluntary.

• Internationally accepted protocols must govern any polygraph examination.

• Contrary to general belief, nervousness will not cause a person to ‘fail’ the polygraph examination.

• Use of medication (the prescribed or advised dosage) will not affect the polygraph examination or the result.

• Over-dosage of medication or illegal drugs may suppress responses during a polygraph examination.

Refer here for a full explanation?