What is the polygraph device?

The polygraph device (lie detector) is a scientific instrument utilized during specific validated protocols and sequences. It simultaneously records changes in physiological variables — blood pressure, pulse, perspiration, and others — while the examinee is asked a series of questions. The data and graphic charts are analyzed and interpreted by an experienced polygraph examiner.

How accurate is the polygraph test?

Scientific studies over the last 100 years have shown that when administered professionally by an experienced examiner, the accuracy of polygraph results exceeds 90%. The GPS examiner is highly experienced, certified, and a full member of the American Polygraph Association (APA).

How many questions can I ask in a polygraph test?

Scientifically validated lie detector techniques limit a single test to no more than four (4) pertinent questions. This is a professional standard to ensure a reliable outcome. Questions must address specific actions — not feelings or thoughts. The examiner will help you compile the best questions to cover all concerns.

How often are polygraph examinations used?

Polygraph examinations are commonly conducted by examiners in the private, law enforcement, and government sectors in over 90 countries worldwide.

How long does a polygraph test take?

The polygraph test procedure includes a pre-test interview, the test itself, and a post-test phase. Depending on the subject and format chosen, the entire procedure typically takes between 1.5 and 2 hours.

What type of polygraph device does Global Polygraph & Security use?

Global Polygraph & Security uses the Lafayette Instruments LX 6 computerized polygraph device, equipped with the most advanced sensors and lie detection technology currently available.

Can I take a polygraph test if I have a health condition?

Examinees with health conditions should consult their physician prior to testing. During the pre-test phase, a medical release form must be completed disclosing any known medical or psychological conditions and medications. If your condition is stabilized, it generally should not prevent you from taking the test. Some temporary conditions such as the flu or acute pain may require rescheduling.

Can I take the polygraph test at my home?

From a professional standpoint, it is much better to take the test in a neutral environment such as the examiner's office. While testing at home is not advised, some unique circumstances may be considered as long as certain professional pre-conditions are met. You may discuss your situation during the initial consultation.

Can I fool the polygraph test?

It is highly unlikely that you will be able to fool an experienced examiner using advanced polygraph technology. Counter-measure techniques found online are unreliable and will typically result in a Deceptive Indicated (DI) or Purposely Non-Cooperative (PNC) outcome. If you intend to use counter-measures, it is better not to take the test.

If I failed the polygraph test, can I immediately retake it?

If results showed significant responses indicating deception (DI), there is generally no point in immediately retaking the test. However, if new information is disclosed following the test, the examiner may consider a re-examination — which is a completely new exam with new fees, usually on a different date and with modified questions based on the new information.

What areas does Global Polygraph & Security serve?

Global Polygraph & Security serves the Greater Los Angeles area, including Los Angeles, Beverly Hills, Century City, Santa Monica, Glendale, Pasadena, Long Beach, Burbank, Malibu, West Hollywood, Culver City, Manhattan Beach, Irvine, Orange County, Ventura, and hundreds of additional cities throughout Southern California.

Criminal & Legal Cases

Where Polygraph Testimony Meets the Courtroom

A plain-language guide to how polygraph examinations are actually used in criminal defense, prosecution, law enforcement, and post-conviction supervision — and the limits courts place on the results.

Overview

What a "legal case" polygraph exam actually is

When attorneys, investigators, or individuals commission a polygraph examination in connection with a criminal or civil matter, the exam itself doesn't change — but the stakes, the documentation, and the question formulation do. A legal-case examination is built around a specific, disputed fact: did the person commit the act in question, make the statement in question, or violate the term in question. The examiner works from a structured protocol (commonly a Comparison Question Test or Directed Lie format), so the resulting chart and opinion can withstand scrutiny from opposing counsel, a supervising officer, or a court.

Below is a working map of where polygraph testing shows up across the criminal and legal system, what courts currently do with the results, and what to expect from the process.

Where It's Used

Criminal & legal contexts for polygraph testing

Defense-requested examinations

Defense counsel commissions a private exam — often before charges are filed or before trial — to evaluate a client's account, guide case strategy, or support a request that prosecutors decline to file or reduce charges.

Stipulated examinations

Prosecution and defense agree in advance, in writing, that the results — favorable or not — may be introduced at trial. Roughly half of U.S. states permit polygraph evidence on this basis.

Plea negotiations & sentencing

Because the strict rules of evidence that govern a jury trial don't apply to negotiations or to a judge's sentencing determination, results are frequently used here even in states that exclude the same evidence from trial.

Probation, parole & PCSOT

Post-Conviction Sex Offender Testing (PCSOT) and general probation/parole polygraphs monitor compliance with supervision terms. Courts treat this as an administrative tool rather than trial evidence.

Law enforcement pre-employment screening

Police, sheriff, and federal agencies routinely screen applicants. This use sits outside the Employee Polygraph Protection Act's general private-employer ban, which exempts federal, state, and local government hiring.

Internal affairs & officer-involved incidents

Departments use polygraph examinations during internal investigations, use-of-force reviews, and integrity units, subject to the department's own policy and any applicable collective bargaining agreement.

Admissibility

What courts actually do with the results

Admissibility depends entirely on the jurisdiction and the standard that court applies to expert and scientific evidence. There are two governing frameworks:

Standard	Origin	General posture on polygraph
Frye ("general acceptance")	Frye v. United States, 1923	Excludes polygraph results; a small group of states still apply this test and remain the most consistently exclusionary.
Daubert (reliability factors)	Daubert v. Merrell Dow, 1993	Governs federal courts and most states; polygraph evidence is still excluded as a matter of practice, though the door is theoretically open case by case.
Stipulation exception	State-specific	Roughly half of all states admit results at trial if both sides agreed in writing before testing.
New Mexico	Rule 11-707	The only state that permits routine admission of polygraph results without a prior stipulation, subject to foundational and qualification requirements.

This table describes the general framework and is not a substitute for jurisdiction-specific research. Admissibility rules shift through new case law and legislative action — always confirm current status with a licensed attorney before relying on a polygraph result for any legal purpose.

Process

How a legal-case examination is conducted

1. Pre-test interview

The examiner reviews the case facts, clarifies the relevant issue, and finalizes the exact wording of every test question with the examinee.

2. Instrumentation

Sensors record respiration, cardiovascular activity, and electrodermal response — the three trace lines shown above — throughout each question sequence.

3. In-test question series

Relevant, comparison, and neutral questions are presented in a fixed, validated order, repeated across multiple charts to confirm consistency.

4. Scoring & report

Charts are numerically scored against a recognized technique, and a written opinion — deceptive, non-deceptive, or inconclusive — is issued to the retaining party.

Frequently Asked

Common questions from attorneys and clients

Can a polygraph result get my case dismissed?

Not by itself. A favorable result is leverage in negotiations with a prosecutor or in a bail or sentencing argument — it is rarely, on its own, grounds for dismissal, and its use always runs through your attorney.

If I take a private exam, does the other side get to see it?

Only if you or your attorney choose to disclose it, or if you've entered a stipulated agreement. An unfavorable private result generally stays with you and your counsel.

Is a law-enforcement pre-employment screening the same test?

The instrumentation is the same, but the question structure is different — screening exams cover broad suitability topics (integrity, disqualifying conduct) rather than a single disputed incident.

Do I need my attorney involved before scheduling?

For any exam connected to an open case, charge, investigation, or supervision requirement — yes. Your attorney should approve the question wording and the intended use of the result before testing begins.

Discuss a criminal or legal-case examination

Every case is scheduled confidentially and, where appropriate, coordinated directly with retaining counsel.

Request a Confidential Consultation

This page is provided for general information only and does not constitute legal advice. Polygraph admissibility rules vary by jurisdiction and change over time — consult a licensed attorney about your specific matter.