After a polygraph test, the examiner usually gives you a verbal result the same day and sends a written report to whoever requested the exam, and what happens from there depends almost entirely on who that is. Police treat the result as an investigative lead. Private employers are tightly restricted by federal law in what they can do with it. Federal agencies running security clearance polygraphs cannot disqualify you on the result alone. The chart is only the beginning; your rights and the real stakes diverge sharply from that point on.
The Post-Test Phase
Once the sensors come off, the examiner reviews the physiological data recorded during the test and flags any reactions to specific questions that stood out. You will usually get a verbal summary that same day. A formal written report may take longer.
If any of your responses suggest deception, the examiner typically gives you a chance to explain. Medical conditions, anxiety, medications, sleep deprivation, or even misunderstanding a question can produce physiological spikes that look like deception but aren’t. Your explanations get recorded and folded into a report covering the pre-test interview, the test data itself, and the post-test discussion. That report goes to whoever requested the examination.
In employment situations covered by the Employee Polygraph Protection Act, the post-test phase carries specific legal requirements. Before an employer can take any negative action against you, they must interview you about the results and hand you a written copy of the examiner’s opinions, the questions you were asked, and copies of your charted physiological responses.
The Three Possible Results
Every polygraph produces one of three outcomes, and knowing which one you received is the starting point for everything that follows.
- No deception indicated (NDI). Your physiological responses to the relevant questions were not meaningfully different from your responses to control questions. In plain terms, the examiner did not see signs of lying. In most contexts, this means you move forward in whatever process prompted the test.
- Deception indicated (DI). Your responses to the relevant questions were significantly stronger than to control questions, which the examiner interprets as a sign of deception. This does not mean you actually lied. It means the instrument detected a pattern the examiner associates with deception.
- Inconclusive. The examiner could not confidently call the result either way. This happens when physiological reactions are inconsistent, too subtle, or muddied by outside factors. An inconclusive result is not a failure, and many agencies will offer a retest, sometimes scheduled days to months later depending on policy.
Why a “Fail” Is Not Proof You Lied
The polygraph measures blood pressure, heart rate, breathing patterns, and skin conductivity. It does not measure lying. It measures physiological arousal and assumes that arousal during certain questions correlates with dishonesty. That assumption breaks down regularly. The American Polygraph Association has cited research claiming accuracy rates between 80 and 98 percent, but a major review by the National Academy of Sciences found the scientific evidence for polygraph validity to be weak and the scientific community deeply divided.
Several common conditions can trigger a false positive. Hypertension, heart disease, thyroid disorders, chronic pain, and respiratory problems all distort the baseline readings the examiner relies on. Anxiety is probably the most common culprit: a truthful person who is terrified of being falsely accused can produce physiological responses that look identical to deception. Sleep deprivation raises baseline arousal enough to make accurate testing extremely difficult. If any of these factors apply to you, raise them during the post-test discussion and make sure they appear in the written report.
After a Police Polygraph
If law enforcement administered the test, the result becomes one data point in a larger investigation. Police cannot arrest or charge you based solely on a polygraph result, and the results are almost never admissible in court. What they can do is steer the investigation. A deception-indicated result might prompt detectives to dig deeper into your alibi, interview additional witnesses, or seek a search warrant based on other evidence. A clean result might shift their focus elsewhere, though it does not guarantee they will stop investigating you.
You have no legal obligation to take a polygraph in most criminal investigation contexts. If police ask you to take one, you have the right to refuse, and that refusal generally cannot be used against you in court. If you do agree, understand this: anything you say during the pre-test interview or post-test discussion can be used in the investigation, even if the chart itself is excluded from trial. The polygraph session doubles as an interrogation opportunity, and admissions made during the conversation surrounding the test carry far more legal weight than the chart readings.
After an Employer Polygraph
Federal law heavily restricts polygraph use in the private sector. The Employee Polygraph Protection Act prohibits most private employers from requiring, requesting, or even suggesting that an employee or job applicant take a lie detector test. Employers also cannot use polygraph results to make hiring or firing decisions, and they cannot retaliate against you for refusing.
Narrow Exceptions
The law carves out exceptions. Security firms providing armored car services, alarm system installation, or guard services may polygraph prospective employees whose duties involve protecting certain sensitive facilities or assets. Pharmaceutical companies authorized to handle controlled substances may test prospective employees who would have direct access to those substances.
The most common exception involves ongoing workplace investigations. If your employer has suffered a specific economic loss from something like theft or embezzlement, you had access to the property, and the employer has a reasonable basis to suspect your involvement, they can ask you to take a polygraph. But they must give you a written statement before the test spelling out exactly what incident they are investigating, why they suspect you, and what loss the business suffered. That statement must be signed by someone authorized to bind the company and kept on file for at least three years.
Your Rights Under the EPPA
Even when a polygraph is legally permitted, you have substantial protections at every phase:
- You must receive 48-hour written notice of when and where the test will occur, and you have the right to consult an attorney or employee representative before each phase.
- You have the right to see every question the examiner will ask, in writing, before the test begins. The examiner cannot ask any question during the test that was not provided for your review beforehand.
- You can terminate the test at any point. If you stop early, the examiner cannot render an opinion on your truthfulness.
- The examiner cannot ask about your religious beliefs, political views, racial opinions, sexual behavior, or union activities.
- If a physician documents that a medical or psychological condition could cause abnormal responses, you cannot be subjected to the test.
- Before any adverse action, your employer must interview you about the results and give you written copies of the examiner’s conclusions, the questions asked, and your charted responses.
The protection that matters most: even if the polygraph indicates deception, your employer cannot fire, discipline, or demote you based on the test result alone.
If Your Employer Breaks the Rules
Employers who violate the EPPA face civil penalties of up to $26,262 per violation. A court can order reinstatement, promotion, and payment of lost wages and benefits. You can file a private lawsuit in federal or state court within three years of the violation, and the court may award your attorney’s fees if you win. You can also file a complaint with the Department of Labor’s Wage and Hour Division, which has authority to investigate and seek injunctive relief.
One boundary to be aware of: the EPPA does not apply to federal, state, or local government employers. If you took the test for a government job, law enforcement position, or intelligence role, these protections do not cover you.
After a Security Clearance Polygraph
Many federal agencies and intelligence community organizations use polygraphs as part of personnel security vetting. If you receive a deception-indicated result during a security clearance polygraph, the result alone cannot sink your clearance. Federal policy requires that any potentially disqualifying information surfaced during a polygraph be confirmed by an independent source before adverse action can be taken.
In practice, a failed polygraph often triggers a deeper background investigation, additional interviews, or delays in your clearance timeline. An inconclusive result typically means a retest, though federal agencies are not required to offer one and may exercise discretion based on operational needs. A single bad session does not automatically end your career prospects with the federal government. It does mean your file gets more scrutiny, and the process may take considerably longer.
Polygraph Results in Court
Polygraph results occupy an unusual position in American courts: widely used by investigators but rarely admitted as evidence. In 1923, a federal appeals court ruled in Frye v. United States that scientific evidence must have gained “general acceptance in the particular field in which it belongs” before courts will admit it. The polygraph failed that test and has never cleared the bar in most jurisdictions since.
In 1993, the Supreme Court replaced the Frye standard in federal courts with a more flexible framework in Daubert v. Merrell Dow Pharmaceuticals. Under Daubert, judges evaluate whether scientific testimony rests on testable methodology, peer-reviewed research, known error rates, and general acceptance. That opened the door slightly, and a few federal circuits moved away from a blanket ban. In practice, most federal and state courts still reject polygraph evidence because the error rates remain too high and the scientific community too divided. The Supreme Court reinforced the trend in 1998 in United States v. Scheffer, ruling that a military rule barring polygraph evidence at courts-martial did not violate a defendant’s right to present a defense. The Court noted bluntly that “there is simply no consensus that polygraph evidence is reliable.”
A handful of states permit polygraph results under narrow conditions, most commonly when both the prosecution and defense agree in advance (called a stipulation) to let the results in. Even with a stipulation, courts typically impose additional safeguards. Never assume a favorable polygraph result will be admissible at trial.
Challenging a Result or Getting a Retest
If you believe your result is wrong, your options depend on the context. In a private employment investigation, the EPPA guarantees you a post-test interview where you can explain your responses, and the employer must provide written documentation of the results before acting on them. That documentation gives you and your attorney a foundation to challenge both the process and the conclusions.
For pre-employment polygraphs with law enforcement agencies or government positions, many agencies offer retests after inconclusive results. Timelines range from about a week to six months depending on the agency. A deception-indicated result is harder to revisit. Some agencies allow it; many do not. If you are not offered a retest, you can typically apply to other agencies, and an unfavorable result at one department does not automatically follow you to another.
In private testing, you have the most flexibility. If you paid for the test yourself and got an inconclusive or unfavorable result, you can schedule a retest with the same or a different examiner at your own expense. Private polygraph examinations generally cost between $200 and $2,000, depending on the examiner, location, and complexity.
Roughly 29 states require polygraph examiners to hold a valid license, and examiners operating under the EPPA must maintain at least $50,000 in bonding or professional liability coverage. If you believe your examiner was unqualified, improperly licensed, or violated testing protocols, you can file a complaint with your state’s licensing board where one exists, or with the Department of Labor’s Wage and Hour Division if the test was employment-related.