Are you going for a polygraph test soon? Maybe you’re applying for a government position? Perhaps someone accused you of something? Whatever the reason, being told you have to take a lie detector test comes as a bit of a shock.

What is a polygraph? How accurate is this technology at identifying deception? Are the results admissible in court? These questions will likely be on your mind, and with good reason. The polygraph test’s outcome could change your life’s direction, depending on the reasons for issuing the exam.

This post unpacks everything you need to know about polygraphs, what you can expect from the exam, how to prepare for it, and the outcomes of the results. Are you ready to delve into the world of lie detector tests? Let’s dive right in!

Polygraph Technology Explained

We’ve all heard about lie detector tests before. Whether you saw a person grilled under a polygraph in an episode of Law & Order or read about it in the media, lie detector tests aren’t new to most people. Only when you find out you must endure a polygraph, it becomes part of your experience piquing your interest.

So, what is a polygraph? First, a “polygraph” is the formal terminology used to describe a “lie detector test.” It’s used in various scenarios in the United States and around the world. Typically, government agencies will polygraph employees for pre-employment screening or if they suspect employees of doing something wrong – like espionage.

In most instances, it’s illegal for general employers to use these tests in pre-employment screening, but it differs around the globe. Whatever the reason for the polygraph, the procedure’s goal is to uncover if the examinee (the person taking the test) is telling the truth or if they display deceptive behavior.

You see, the polygraph can’t tell if you’re “lying.” However, it can display bio-feedback to the examiner (the person conducting the test) that you’re being “deceptive.” Deception indicates that you’re avoiding telling the whole story about something or avoiding telling the truth to prevent an adverse outcome.

The polygraph device connects to a computer, usually a laptop, running specialized software. The software reads electrical inputs from the apparatus connected to the examinee. These apparatuses measure the following biological outputs.

  • The examinee’s breathing rate.
  • The examinee’s pulse.
  • The examinee’s blood pressure.
  • The examinee’s perspiration.
  • In some cases, the examinee will use an apparatus, like a motion pad, to assess body movements.

Typically, the apparatus used in the test includes corrugated rubber tubing strapped across the examinee’s abdomen and chest. This equipment records their respiratory activity. Two adhesive electrodes or clips attach to the fingers to measure sweat gland activity, and a blood pressure cuff fits the upper arm for recording cardiovascular information.

Some polygraph procedures require the examinees to sit on a pad that measures muscular contraction. They may also use a finger plethysmograph to monitor blood volume in the fingertip to assess cardiovascular activity and nervous system response to the questions asked during the exam.

Polygraphs don’t include voice stress assessments, but some companies offering polygraph services may consist of a voice stress assessment alongside the polygraph test.


How Do Polygraphs and Voice Stress Analysis Tests Work?

When the examiner starts the polygraph assessment, they give the examinee a basic rundown of what to expect from the test before hooking them up to the system. This induction orients the examinee with the parameters of the test and puts them at ease.

When they begin, the examiner asks the examinee a set of four control questions to establish a baseline for their physiological response to the question stimulus. After they have the baseline, the real test starts.

During the test, the examiner records all the information digitally on the software they use to read the outputs from the equipment attached to the examinee. They monitor these readings, looking for deviations from the baseline readings taken at the start of the test.

The examiner will notice changes in the examinee’s heart rate, blood pressure, skin contractions, or perspiration. If so, they may continually ask the same question over and over to assess your biological response, looking for any deceptive behavior.

Well-trained examiners are experts at interpreting these biological signals and accurately noticing deceptive activity in the examinee. However, since the examiner’s interpretation of the physiological signals is subjective. Because examinees react differently to the environment and how they tell lies, the polygraph isn’t flawless in assessing deception.

When included with a voice stress test (CVSA), it adds more data to the process, giving the examiner another metric to assess deception in the examinee. Some companies may use a voice stress test as a standalone procedure to assess lying without including the polygraph in the process.


What Questions Does the Examiner Ask in a Polygraph Test?

So, what kinds of questions can you expect in a polygraph test? The questions vary, depending on the company conducting the test and the requirements for the client hiring the polygraph company.

For instance, an employer assessing their staff for theft will have different requirements than a government agency conducting its pre-employment screening. However, there are some basic questions found in all polygraph tests. Lets’ look at a few examples to give you an idea of what to expect.

  • Have you experimented with illegal drugs like cocaine, steroids, ecstasy, crystal meth, barbiturates, hallucinogens, LSD, magic mushrooms, or heroin?
  • Have you abused prescription drugs?
  • Have you ever been party to an illegal drug transaction?
  • Have you ever bought or sold stolen goods?
  • Have you or anyone you know committed a crime?
  • Have you had traffic citations in the last year?
  • Have you ever lodged a fraudulent insurance claim?
  • Were you truthful in your responses in your job interview?
  • Have any debt collection agencies issued you a notice of payment?
  • Have you avoided filing taxes?
  • Have you filed for bankruptcy before?
  • Do you have bills that are past due?
  • Do you have a good credit rating?
  • Were you ever fired from a job?
  • Has anyone ever accused you of sexual harassment in the workplace?
  • Have you ever stolen from an employer?

These are just examples of questions you can expect during the polygraph exam. However, they may change in wording, depending on the examiner and their company. There are specific questions the examiner may not ask you, or they risk infringing your rights.

Personal, intrusive questions are not allowed in a polygraph session. Some state licensing laws, including the “Employee Polygraph Protection Act” and “the American Polygraph Association,” state the following.

No examiner should inquire into any of the following areas during a pre-employment or periodic employment polygraph examination except where it may interfere with the examinee’s employment performance.

  • Religious affiliations or beliefs.
  • Opinions of beliefs on racial matters or ideology.
  • Political affiliations or beliefs.
  • Associations, beliefs, or lawful actions regarding labor organizations or unions.
  • Legal sexual activities or preferences


How Do You Prepare for a Polygraph?

If you have to undergo a polygraph, there are actions you can take to prepare for the event. It’s not illegal or against the procedure to prepare for a polygraph. For instance, you could read this article on what to expect in the polygraph exam, and the examiner would not consider that deceptive behavior.

However, if you were to read up on how to intentionally beat or evade a lie detector test, that could be a problem. The examiner may ask you a question like, “did you read any material on how to beat or alter the outcome of a polygraph or lie detector test?”

Here are some tips on what to do the day before your exam.

Get Informed

When people fear polygraph exams and don’t know what to expect, it may alter the outcome of the test results. So, informing yourself about what to expect is the best way to put your mind at ease. If you have any questions about the polygraph, you can forward them to your employer or the polygraph company conducting the test.

Keep Your Routine & Get Some Sleep

Don’t change anything in your normal routine. For example, if you normally eat breakfast, don’t skip it on the test day. The changes this makes to your biochemistry may through off the results. Don’t drink alcohol the night before the test; avoid smoking before entering the exam room.

Get a good night’s sleep before the exam. If you’re up all night worrying about the test, it’s better to reschedule it. When you feel tired and lethargic, taking the polygraph will change your physiological responses to the questions.

Don’t use sleeping medication unless you have a prescription, and avoid sleep supplements like melatonin if you don’t use it regularly.

Just Breathe and Relax

Put the test out of your mind the night before the exam. Watch TV or read a book and take your mind off the following day’s events. When you wake up on the morning of the test, go through your normal routine.

Before going into the exam room, monitor your breathing and headspace, and try to keep yourself calm. If you have nothing to hide, you have nothing to worry about.


How Do You Pass a Polygraph, and Can You Cheat?

When you enter the exam room and start the test, the examiner will ask questions with yes or no answers. Sometimes, they may ask you to extrapolate your answer if they feel it warrants further investigation.

For instance, if they ask you if you’ve used illegal drugs in the last year and you say yes, they may ask you what drug it was and when you last used it. If you can’t recall the information, don’t think about it; just say, “I can’t recall.” Thinking about it throws off your physiological response and may appear deceptive to the examiner.

So, can you cheat on a polygraph? The answer is it’s highly unlikely you’ll pull it off if you’re concealing information. People have tried many tricks in the past, such as placing a thumb tack in the front of their shoe and pressing on it when answering a question.

This strategy interrupts the physiological signals sent to the instrumentation, giving an inaccurate reading to the software monitored by the examiner. Other tactics include clenching your sphincter while answering.

In reality, none of these tactics work, and the examiner will likely pick them up. If they suspect you’re using these tactics, it’s basically an immediate fail. Even if you manage to fool the technology, a trained examiner has the experience to detect deception in your voice, micro facial expressions, and body language.

They’ll record the exam and review the footage after the interview. They assess these physiological movements in the review to determine if you’re displaying deceptive behavior, and they’ll likely catch you if you’re lying.


Is a Polygraph Ever Wrong?

So, is a polygraph result ever wrong? Can you ask to repeat the exam if you fail? The polygraph isn’t infallible, and there are several reasons why you might end up failing, even though you’re being truthful with your answers. The biggest reason why truthful examinees fail is due to nervousness attached to the emotional pressure of the situation.

The polygraph examiner may also be new to the job and need more experience to assess the examinee correctly. They may fail to communicate what to expect to the examinee before undergoing the test. As a result, the examinee produces overly-emotional responses that throw off the results. Or the examiner may incorrectly interpret the results because they need more training or experience.

Since the polygraph examiner and their company realize the extent of the severity involved with a failed polygraph, they take countermeasures to ensure they don’t cause a false result. However, despite their best intentions and practices, there’s always the potential for an incorrect result, but it’s rare.

Given the potential for false results, we have to ask ourselves how accurate the polygraph exam is and if it’s a reliable tool for uncovering if someone is lying.

According to the U.S. Congress Office of Technology Assessment, “significant error rates are possible, and examiner and examinee differences and the use of countermeasures may further affect validity.”

This statement was from 1983, showing that the problem of false results with polygraphs is an ongoing problem with an extensive history. However, it doesn’t account for the leaps and bounds in polygraph technology in the last four decades since that statement.

In 2003, the National Academy of Sciences issued a report calling polygraphs “unreliable, unscientific, and biased.” The NAS states that 57 out of 80 polygraph exams conducted in a controlled study featured inaccuracies.

However, the changes in digital software platforms and equipment sensitivity combined with advances in examiner training are not considered. In the last 20 years since the NAS study, digital tech has advanced exponentially in the field of polygraph.


What Happens If You Fail the Polygraph Exam?

After completing your polygraph test, the results go to authorized persons, as stipulated by the American Polygraph Association’s Standards and Principles of Practice and state licensing laws. Authorized persons include the examinee and the company, corporation, or agency requesting the polygraph.

Let’s say you fail a polygraph; what then? The failure could be because you intentionally lied in the test or because you were overly emotional during the exam, adversely affecting the outcome. Some employers may also use the polygraph as an excuse not to hire you because they don’t like you.

The reality is, if you fail a pre-employment screening, you can ask for a retest, but you’re likely not going to get approval, or the results of the second test won’t matter – it’s a dead end for most employers and prospective candidates.

If you fail, the prospective employer cannot divulge your test results to another prospective employer. So, if you fail, it’s better to write off the experience and continue your job search.


In Closing – Who Requires Polygraph Exams for Employment?

Who can legally use polygraphs to assess you for pre-employment? In most industries, it’s against the employment act to use polygraphs to test candidates before hiring them. However, there are exceptions in government agencies, the legal community, and the private citizenry.

Law Enforcement Agencies

These institutions include state and federal law enforcement agencies and local law enforcement agencies such as sheriff’s departments and police forces.

Legal Communities

These institutions include U.S. and District Attorney Offices, Public Defender Offices, Parole & Probation Departments, and private law departments. The powers of polygraph also extend to the court system in cooperation with parole and probation officers and therapists monitoring convicted sex offenders. The court may also polygraph attorneys involved in civil litigations.

Government Agencies

These institutions include the FBI, the CIA, the NSA, and the DOD (Department of Defense Agencies).

Private Sector

Corporations and companies may use polygraphs under the guidelines, restrictions, and limitations of the Employee Polygraph Protection Act of 1988 (EPPA). Private citizens may also undergo polygraph exams in personal matters that don’t involve the criminal justice or legal system.


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