Are polygraph results admissible in court? Can law enforcement or your employer use the outcome of a polygraph exam against you in your case? It’s a touchy topic, and many assume there’s no way the court will use polygraph results against them. 

However, this may or may not be the case. It depends on the situation and the legislation in your state. This post unpacks the facts surrounding the admissibility of polygraph results as evidence in court. We’ll give you everything you need to know on this subject to help you understand your rights. 


What Is a Polygraph Exam? 

A polygraph exam is a test designed to uncover deception. A subject will sit in a chair connected to instrumentation and software. A qualified examiner asks them a series of questions relating to the matter at hand, and the examinee provides yes or no answers to the questions. 

A polygraph exam can take anywhere from 30 to 90 minutes, depending on the situation at hand. At the end of the test, the examiner will review recorded footage of the session and the test results, notifying nominated parties of the test results. 


Why Would I Have to Take a Polygraph Exam?

Law enforcement or an employer may request you to take a polygraph exam for several scenarios. If you’re accused of a crime, the police could ask you to take a polygraph to prove your innocence. If your employer suspects foul play at work, such as theft, sexual harassment, or embezzlement, they may request you to take a polygraph. 

Or an employer, such as the Department of Defense or CIA, may require you to take a polygraph as a part of your pre-employment screening process. The purpose of the polygraph is to uncover deceptive behavior relevant to the hiring process or a criminal investigation by authorities. 


How Accurate Are Polygraph Exams?

There are two sides to this argument. Advocates of polygraph technology claim the exam is up to 98% effective and accurate at uncovering deceptive behavior. The polygraph equipment measures changes in pulse and reparation rate, blood pressure elevations, and skin sweat gland activity, compiling this data to prove deception. 

The polygraph equipment connects to a laptop running specialized software interpreting the signals sent from the equipment connected to the examinee. Experts suggest the “fight-or-flight” response produced by the sympathetic nervous system is impossible to cheat, providing physiological responses that prove the examinee is lying. 

Then, some state polygraph technology is only 60% to 70% accurate. They point to studies showing these results and claim that polygraph results are easily manipulated to whatever agenda the examiner wants to prove. Both proponents of the technology and its detractors have valid points to their arguments.  


When Is a Polygraph Exam Admissible in Court?

The jurisdiction where the polygraph took place is the primary factor concerning the admissibility of the exam results in court. Admissibility varies widely from state to state, falling into two categories. Some states entirely disallow polygraph results in court, and others do, with the caveat that the exam results come with stipulations from parties involved with the polygraph exam. 

In cases where results are admissible in court, the prosecutor and exam subject must agree on the admission of the test results. 23 states allow polygraph results as evidence in court, provided they meet these conditions. 

In most instances of polygraph results being used in cases, it’s for civil rather than criminal cases. For example, job candidates are refused a position, or employees are fired from their job. A good example is in the state of Georgia, where defendants who suffer financial or reputational harm from a false failed result on a polygraph test may sue the test administrator for damages and court costs.

Some states find polygraph results entirely inadmissible in court even when all parties agree to its use. These states include Texas, New York, Pennsylvania, Washington, D.C., and Illinois. The Employee Polygraph Protection Act of 1988 is the primary driver behind the reason polygraph exam results are inadmissible in court. 

However, the courts also find the lack of uniform standards applying to the use of the results in court. In most instances, it’s entirely up to the judge presiding over the case and the state laws surrounding using polygraph results as evidence. 

The case of Frye v. U.S. in 1923 was the first to see the striking of polygraph results as a reliable form of evidence. In the years before the case, the courts passed the Federal Rules of Evidence (FRE), giving judges more control over the admissibility of polygraph results as evidence.

The case of Daubert v. Merrell Dow Pharmaceuticals in 1993 saw the U.S. Supreme Court rule polygraph evidence could be used in evidence if it met five factors of the “Daubert standard.” In 1998, the case of U.S. v. Scheffer saw the U.S. Supreme Court issued a statement saying polygraphs were not admissible as evidence unless the judge allowed it in line with the Daubert standard.

However, the biggest shift in policy regarding the admissibility of polygraph results in court came from the introduction of The Employee Polygraph Protection Act in June 1988. The Act applies to most civil court cases in the private sector concerning the use of polygraphs in the workplace and the admissibility of those test result in court. 

It’s important to note that the law doesn’t apply to most government agencies, such as law enforcement, national security, and the defense sector.

However, it does not apply to government workers (e.g., federal, state, and local government agencies) or those hired by security firms or pharmaceutical companies. The Act also has separate definitions for “polygraph” and “lie detector” tests and what circumstances and procedures are outlawed under Federal law.

The following states will likely allow the admissibility of polygraph results based on past case authority. 

  • Alabama
  • Arizona
  • Arkansas
  • California
  • Delaware
  • Georgia
  • Idaho
  • Indiana
  • Iowa
  • Kansas
  • Nevada
  • New Jersey
  • New Mexico
  • North Dakota
  • Ohio
  • Utah
  • Washington
  • Wyoming


When Are Polygraphs Inadmissible in Court?

Polygraph results are not admissible in court when the state doesn’t recognize these results as valid or when both parties to the exam do not consent to use the results in the case. The results may also be invalid if state law prohibits the use of polygraph exams in specific situations or when judges refuse the admittance of the results.

This denial of polygraph results as admissible evidence comes from studies by “experts” in the late 1980s stating polygraph results are inaccurate and often incorrect. However, it’s important to note that polygraph technology has advanced significantly since these times. The introduction of computerized systems running software governed by algorithms is not considered. 

So, the Act doesn’t include the advancement in polygraph technology in the last 35 years since these studies were published. It’s clear that there should be a review of this legislation, especially since proponents of polygraph tech state its results are up to 98% accurate. 

Still, the law relies on the results of dated studies stating there may be defects in the polygraph device recording the results or inherent bias from the polygraph examiner altering the test results. Polygraphs tend to provide inconsistent results due to physiological indicators implying one or more emotional responses other than a guilty answer. 

Proponents of the EPPA state that other methods of gathering evidence are more effective than polygraph results at supporting the prosecutor’s case. As such, polygraph results should only appear in case evidence as the last resort in those states that accept them as evidence. 

There is also speculation by proponents of the Act that, in the past, law enforcement manipulated polygraph evidence to support their case in court. Law enforcement officials may administer the test in situations where the test subject is incapable of thinking clearly or achieving a failed test. This behavior would be against the defendant’s constitutional rights. 


If I’m Arrested, Can Law Enforcement Force Me to Take a Polygraph Exam? 

As mentioned, The Employee Polygraph Protection Act of 1988 and state laws make forcing a person to undergo a polygraph exam illegal. The subject of the exam must willingly consent to a polygraph test, and they may not be bullied or coerced into it. They have the right to refuse the exam.

However, should you agree to willingly take the lie detector test, law enforcement may use the exam results as evidence against you in court. If you refuse to undergo the polygraph exam, the prosecuting authority may not use this fact against you in court. 

There is no legal obligation forcing you to take a polygraph exam, regardless of what law enforcement officials tell you at the time of your arrest or while in holding. Finally, it must be noted that if the court refuses to admit polygraph results as evidence, the prosecutor can use a final report to support the case against you. 

So, if law enforcement or the prosecuting authority attempts to coerce you into taking a lie detector test, you can contact a criminal law attorney to protect your constitutional rights. 


Can I Take a Polygraph exam to Prove My Innocence?

It’s generally not recommended for suspects to take polygraph exams to prove their innocence. However, if the suspect or defendant is confident in their case, they may request a polygraph exam to prove their innocence. 

It’s important to note that polygraph exams, while effective, are not viewed by most courts as reliable forms of evidence in civil or criminal cases. Prosecutors will argue that the examinee may be able to manipulate their responses to appear innocent, even if they’re guilty. 

Also, suppose the defendant or suspect willingly takes the polygraph test. In that case, they may still fail due to intimidation tactics used by law enforcement during the examination that make them feel nervous. These feelings of anxiety and stress may cause them to fail, despite their innocence. 

As a result, the prosecuting authority may use these test results as evidence in court, despite the suspect or defendant being innocent. 


Do I Need a Lawyer If My Employer or Law Enforcement want Me to Take a Polygraph Exam? 

The laws surrounding the legality of polygraph exam results being admissible in court may be challenging to navigate without the assistance of an attorney experienced in these matters. Each jurisdiction has different procedures for administering polygraph exams and interpreting the test results.

There could be clauses in the regulations that don’t apply in all states. If you have questions regarding the validity of a polygraph exam request or its results, you should speak to a criminal defense attorney immediately. Your lawyer will discuss the exam results and explain their impact on your case. 


In Closing – Can I Beat a Polygraph Exam?

Some individuals may willingly take the polygraph exam to try to skew the results in their favor. There are plenty of stories of people that supposedly “beat” the polygraph. Even the law makes it seem that polygraph tech is unreliable and inconclusive, building confidence in people that they can manipulate the exam and its results. 

However, polygraph technology has seen huge advancements in the 35+ years since these statements of unreliability were brought about by so-called “experts.” Today’s computerized polygraph systems are far more accurate than those used in the late 1980s and early 1990s. 

Assuming you can beat a modern polygraph exam running AI algorithms is dubious, and your display of hubris will likely work against you. Not only do you have the software and systems to beat, but you also have to get around the examiner. 

Today’s examiners undergo extensive training. You might wind up with an examiner with thousands of polygraph rests under their belt. They’ll know how to read the polygraph results and are experts in questioning you and identifying deceptive behavior. 

Don’t assume sticking a thumbtack in your show or squeezing your sphincter will help you beat the polygraph. These old wives’ tales may have worked 40 years ago, but they are largely ineffective against modern polygraph systems. Don’t tempt fate, or it will likely work against you.