An inconclusive polygraph result is not a fail. It means the examiner could not decide whether your answers were truthful or deceptive, so no call was made in either direction. What happens next depends on why you were tested: a job applicant, a security clearance candidate, a criminal suspect, and someone on supervised release all face very different consequences, but none of them are treated as having lied simply because the chart came back unreadable.
What “Inconclusive” Actually Means
A polygraph examiner scores your physiological reactions, including changes in heart rate, blood pressure, breathing, and skin conductivity, and reaches one of three conclusions: no deception indicated, deception indicated, or inconclusive. The first two are calls. The third is the examiner declining to make a call because the data was too ambiguous or too noisy to score.
That distinction matters. Inconclusive does not mean the examiner suspects you lied but could not prove it. It means the recording did not clearly point in either direction. Field studies reviewed by the Office of Technology Assessment found inconclusive rates ranging from near zero to 25 percent of examinations, depending on the technique and the testing conditions. In other words, uninterpretable results are a normal feature of the method, not a signal about the person taking the test.
Why Tests Come Back Inconclusive
The polygraph relies on involuntary nervous-system responses as a proxy for deception-related stress. Anything that disrupts those signals can muddy the data, and none of the common causes have anything to do with honesty:
- Medical conditions such as heart arrhythmias, chronic pain, sleep apnea, and disorders affecting the autonomic nervous system can produce erratic readings.
- A wide range of commonly prescribed medications can alter autonomic responses, blurring the line between stress-related and drug-related changes.1PMC. Beyond the Polygraph: Deception Detection and the Autonomic Nervous System
- Acute anxiety or fatigue can elevate your baseline so much that the contrast between relevant and control questions flattens out.
- Sensor malfunctions, loose attachments, and outside noise can degrade the recording.
- Poorly worded questions or scoring mistakes by the examiner can push a borderline chart into inconclusive territory.
Because none of these causes reflect dishonesty, no formal scoring system treats an inconclusive result as a failed test.
What Happens Next: The Retest
The most common next step after an inconclusive result is a second examination, sometimes with a different examiner, in the hope of getting a cleaner set of data. U.S. Customs and Border Protection, for example, may invite an applicant to retake the exam after an inconclusive outcome.2Office of Inspector General, DHS. OIG-18-68 – Most Complaints about CBP’s Polygraph Program Are Unfounded
Whether you get that second chance, how long you wait, and whether more than one retest is allowed varies by agency. Some cap retests at one or two; others publish no limit. If a medical condition or medication may have interfered, say so before the retest so the examiner can adjust the process.
Expect some delay. In hiring, an inconclusive result may push additional background checks to the front of the line. In an investigation, it may push the detective toward other evidence. What it should not do, in any legitimate setting, is produce an adverse decision on its own.
If the Test Was for a Security Clearance or Federal Job
Federal agencies that handle classified information, including the FBI, CIA, NSA, and Defense Intelligence Agency, administer polygraphs to applicants and, in some roles, to current employees on a recurring basis. The Employee Polygraph Protection Act does not reach federal, state, or local government employers, so these agencies face no statutory ban on testing.3Office of the Law Revision Counsel. 29 USC 2006 – Exemptions
Federal policy does, however, limit what the agency can do with the result. Security Executive Agent Directive 4, which governs security clearance adjudications across the executive branch, states that no adverse action may be taken solely on the basis of a polygraph technical call, including “no opinion,” unless the agency has additional credible derogatory information from a separate source.4Office of the Director of National Intelligence. Security Executive Agent Directive 4 – Adjudicative Guidelines
In practice, an inconclusive result during clearance processing usually leads to a retest. If the second test is also inconclusive, the adjudicator decides based on the rest of your file. Many applicants assume an inconclusive result is quietly treated as a fail. The written policy says otherwise.
If You’re a Private-Sector Employee
If you work for a private company, the Employee Polygraph Protection Act gives you strong protection. The law prohibits most private employers from requiring, requesting, or even suggesting that an employee or applicant take a polygraph, and from firing, disciplining, or otherwise retaliating against you for refusing.5Office of the Law Revision Counsel. 29 USC 2002 – Prohibitions on Lie Detector Use
A handful of exceptions exist. Companies whose primary business is security services, such as alarm, armored car, and guard firms, as well as pharmaceutical manufacturers and distributors, may test certain applicants and employees. A private employer may also request a polygraph from an employee reasonably suspected of involvement in a specific workplace theft or loss causing economic harm, but only if strict procedural requirements are followed.6U.S. Department of Labor. Employee Polygraph Protection Act
Even when an exception applies, you can refuse or stop the test at any point, and the employer cannot use the results as the sole basis for discipline or termination. For a private-sector employee, an inconclusive result is legally almost irrelevant. If your employer pressures you based on one, you can file a complaint with the Department of Labor’s Wage and Hour Division.
If You’re on Post-Conviction Supervision
Polygraphs are commonly used to monitor people on probation or supervised release for sex offenses. The federal judiciary uses three types of examinations in this setting: sexual history disclosures, periodic maintenance checks to verify compliance with supervision conditions, and issue-specific follow-ups when earlier tests raise concerns.7United States Courts. Chapter 3 – Polygraph for Sex Offender Management
Under approved federal judiciary procedures, polygraph results may be used to increase the level of supervision or modify a treatment plan, but a polygraph result cannot be the sole basis for revoking supervision.7United States Courts. Chapter 3 – Polygraph for Sex Offender Management An inconclusive result typically triggers a follow-up examination rather than an immediate consequence. The underlying principle is the same: an unreadable chart does not prove a violation.
If the Test Was Part of a Criminal Investigation
Polygraph results are inadmissible in most American courtrooms. In United States v. Scheffer (1998), the U.S. Supreme Court upheld a military rule banning polygraph evidence outright, noting that the scientific community “remains extremely polarized” about reliability and that accuracy estimates in the research literature range from 87 percent down to roughly the level of a coin flip.8Justia. United States v. Scheffer, 523 US 303 (1998)
Federal Rule of Evidence 702 requires that expert testimony be based on reliable principles and methods, reliably applied to the facts.9Legal Information Institute. Federal Rule of Evidence 702 – Testimony by Expert Witnesses Most federal courts have found polygraphs do not clear that bar. A narrow exception exists in some federal circuits and a handful of states where both parties stipulate in advance that the results will be admitted; the Eleventh Circuit, for instance, has permitted polygraph results under that condition.10U.S. Department of Justice. Criminal Resource Manual 262 – Polygraphs Introduction at Trial Stipulation is rare, and most defense attorneys advise against it. Military courts-martial prohibit polygraph evidence entirely under Military Rule of Evidence 707, with no stipulation exception.
So if your polygraph came back inconclusive during a criminal investigation, it almost certainly will never reach a jury regardless of what it said. The test matters more in the investigative phase, where detectives may use it to decide where to look next, than in the courtroom.