What Polygraph Examinations Are

The term polygraph – literally meaning “many writings” – pertains to the method of simultaneously recording various physiological activities and observing any pattern changes in them.

Those who wish to determine the truth behind a statement will often rely on a polygraph examination, or in simpler terms, a lie detection test. Law enforcers often utilize this method of examination to determine the innocence of an individual.

What Comprises a Lie Detector Test

A typical lie detector test includes three areas:

  • a pre-test interview wherein the required paperwork is collected and the examinee is asked a few short questions,
  • chart collection wherein different polygraph charts will be collected by the examiner, and
  • the analysis of test data wherein the generated charts are studied and interpreted. This is when the results are determined.

If deemed appropriate by the examiner, the examinee will be allowed to explain his or her responses to the questions given during the examination.

When to Require a Polygraph Test

A polygraph test can be requested or conducted in specific scenarios, such as:

  1. When identifying individuals who are considered threats to national security.

This is one of the main purposes of a polygraph test. Departments that usually make use of this kind of test are the Federal Bureau of Investigation, Central Intelligence Agency, National Security Agency and other federal bodies that deal with uncovering crimes and threats to national security.

  1. When individuals are involved in criminal and civil cases.

There are criminal trials and civil lawsuits that require more than hard evidence. Sometimes, the trustworthiness of a witness must be proven as well.  This is where a polygraph examination comes in.

There are states that allow polygraph examiners to testify and state for the record whether the person in question is telling the truth or not. Taking the polygraph test isn’t mandatory, but its results may influence the verdict of a case.

  1. When job applicants go through the pre-employment screening process.

Most private employers are prohibited to       use polygraph tests for their applicants. Companies offering sensitive jobs however, such as those in law enforcement, require job applicants to undergo a polygraph test.

Should a company require a polygraph test for its applicants, the rights of the applicant must be discussed. The employee should also be aware of the situation that necessitates the test as well as the reason for the examination.

  1. When there is a need for internal investigations.

Employees of financial institutions such as banks often have access to valuables and large amounts of money. And so, polygraph examinations are used to establish an employee’s honesty. The tests are also done when employees are suspected of violations of banking laws or of being involved in fraudulent activities.

Similarly, retail establishments and businesses that maintain inventory are particularly susceptible to pilferage and employee theft. Lie detector tests can be ordered for employees who are suspected of these infractions. There are, however, legal limitations in conducting such tests.

  1. When the court system needs to monitor the activities and behaviour of its wards.

There are cases when the courts need to keep an eye on suspects, convicts, and parolees over a period of time. This usually happens when there are still ongoing investigations that these personalities may have important knowledge about. This may also be the case when they are suspected of still being involved in the same criminal activities that they are in trouble with the law for.

Is a Polygraph Test Reliable?

Like any other tests, the tests are not 100% accurate. Errors are usually referred to as a false negative and a false positive:

  • False negative – You’re lying, but the machine says you’re telling the truth.
  • False positive – You’re telling the truth, but the machine says you’re lying.

Errors like these can be damaging. Not only can it affect the case being investigated but also the examinee himself. That’s why certain procedures are in place to detect any conditions that could lead to a false negative or a false positive result.

There are various causes for error – it could be due to the examiner not being able to prepare the examinee for the test or due to inaccurate interpretation of data.

Still, like any other examinations involving human intervention, errors can happen even if everything else was done correctly.

Trust the Experts

You really are not sure if you can truly tell if someone’s telling the truth or not. You might even fall prey to those who are good at making others believe that he is being honest even if he isn’t. You will be in better hands if you leave the task to experts in lie detection.

There are different factors to consider in choosing a polygraph examiner. For one, the company should have the necessary background and experience to perform such an important test. It should also have the right equipment to record audio and video properly with the suitable quality.

The examiner you should choose must be able to perform all tasks related to the polygraph exam – these include the pre-test procedures, the announcement of results, and the follow-ups if necessary.


A polygraph test gathers a lot of information. The most important of these is the individual’s honesty and truthfulness in whatever it is that he is saying, whether it is about a crime that he has supposedly committed or witnessed or about several details that he indicated in his job application. Only trust a company that provides expert lie detection services using the most reliable measuring tools to yield the most accurate results.


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