Frequently Asked Questions

The polygraph is an impartial, delicate, and complex medical instrument that records the physiological changes of an examinee while subjected to stimuli. It monitors respiratory, electro-dermal, and cardio activity. When an individual lies, their sympathetic system goes into a "fight or flight" reflex causing physiological changes. These changes are recorded by the polygraph instrument onto a moving chart. 

It is important to note that a polygraph does not include the analysis of physiology associated with the voice. Instruments that claim to record voice psychological stress are not polygraphs and have not been shown to have scientific support. 

Click on the button below to see how a properly administered polygraph test is conducted by the United States Military.  

The general consensus within the polygraph profession is that, at best, someone might deceive an untrained or unskilled examiner.  

Many studies have been done over the years that have documented the accuracy of polygraph to determine truth vs deception. Generally, the studies found the polygraph’s accuracy to be in the 87% to 92% range. 

Independent research conducted by some of the nation’s top scientists concluded that, while the polygraph technique is not infallible, research clearly indicates that when administered by a competent examiner the polygraph test is the most accurate means available to determine truth and deception.

As published in the New York State Division of  Probation and Correctional Alternatives (DPCA) bulletin  (January 2009 Research Bulletin 3 page11): https://www.criminaljustice.ny.gov/opca/pdfs/sopolygraphresearchbulletin3.pdfthe 

The American Polygraph Association’s web site offered the following regarding laboratory and field examinations:

• 12 studies of the validity of 2,174 field

examinations had an average accuracy of 98%.

• 11 studies involving the reliability of

independent analyses of 1,609 sets of charts from field examinations confirmed by independent evidence had an average accuracy of 92%.

• 41 studies involving the accuracy of 1,787 laboratory simulations of polygraph examinations had an average accuracy of 80%.

• 16 studies involving the reliability of independent analyses of 810 sets of charts from laboratory simulations had an average accuracy rate of 81%.

Inherently, field tests are acknowledged as being far more accurate than laboratory tests. Unlike laboratory testing, field tests involve real crimes and consequence to the test subjects. 

There will always be test subjects who try to beat the polygraph test. We use the latest countermeasure peripheral hardware and techniques to identify individuals who try to cheat the test. Polygraph measures the level of nervousness throughout the test which simply cannot be turned off between questions. 

It is important that you are well rested, adequately hydrated, sober and comfortable when you arrive for your test. Bring any documents or media that you would like the examiner to review, prior to your test. We must have access to an upper arm to fit you with a blood pressure cuff. Please avoid wearing clothing that restricts access.  

• At least 6 hours of sleep during the last 24 hours 
• No alcohol consumption within 8 hours of being tested 
• No street drugs within 24 hours of being tested 
• Provide a list of all prescribed medications you are taking 
• Drink plenty of water. Hydration is important. 

Bring any prescriptions, or a list, that you are currently taking. You must avoid consumption of alcohol and/or street drugs prior to your test. We do not recommend researching polygraph on the internet before your test. Most often, the information provided by anti polygraph sites is inaccurate and misleading, and will only give you a false perception of the test. 

Your polygraph test will usually take approximately two hours and sometimes longer, for most types of tests. If you are being tested for a law enforcement position, the examination process is more detailed and will often take longer. The examination consists of 3 phases; a pre-test interview, collection of charts, and analysis of your charts.

During the pre-test interview we will explain how the polygraph works, discuss the issue in question, then develop and review all questions to be asked. This stage is normally the longest to complete. We will construct questions from the information you provide regarding the test issue. All questions are reviewed with you before testing begins. All questions asked will meet the rules for the latest polygraph techniques to ensure testing accuracy is in compliance with the American Polygraph Association. 

If you are being referred by a sex therapist as a component of probation or parole, we will construct your test questions based on the therapist’s requests. The agencies of law enforcement candidates generally offer a polygraph packet that is prepared in advance of the test. We can provide a test packet to candidates if necessary, upon request. Employers who refer an employee for testing must meet EPPA requirements prior to testing and should secure the mandatory ”48 Hour Notice” when being tested for a loss.  We offer all required forms in our “employer“ section under the “Polygraph” tab. 

All questions are discussed with you thoroughly before the test commences and will be answered with a “yes” or “no” response only.  A polygraph test will consist of two or three “relevant” questions to address the issue you are trying to resolve.  All too often, some clients have the misconception that an endless list of questions can be presented. You are limited to three relevant questions. Other questions are asked during the testing phase that are formulated by the examiner. 

During the in-test phase you will be attached to the polygraph Instrument. The set of questions that were developed during your interview will be asked on several occasions, while on instrument. As you answer the questions, your physiological data will be continuously collected, measured and recorded in the form of a moving chart.

We do not allow anyone in the examination room during the instrument testing phase with the exception of a certified interpreter or the examinee’s attorney. Parents can decide if they want to be present in the room for a child’s in-test phase. This is standard procedure to eliminate distractions and obtain unobstructed results.  

Once we have collected your polygraph charts, we will analyze the results before providing a decision as to your truthfulness or deception to the given issue.
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During the post-test phase, your chart data is analyzed by means of a scientifically based objective numerical quantification system. This will render one of the following results:

No Deception Indicated: You are telling the truth.
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Deception Indicated: You are not telling the truth.
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Inconclusive: The evaluation of your charts rendered an inconclusive finding. 

(This only occurs with approximately 5% of all polygraph tests)

If the physiological data recorded on the polygraph charts indicate reactions to one or more of the questions asked during the examination, you will be provided the opportunity to explain these reactions. In some instances a question may be reworded or a second test is written and administered. 

In most instances, we are able to provide final results at the completion of your test. You are entitled to a report which details your personal information, photo, basis of test, pertinent questions asked, the method used to evaluate your data, and the end result. 

All recordings and supporting data are retained by LVPI for three years.  We only provide video to attorneys that you authorize. Your test will not be released, discussed with, or acknowledged to anyone without your prior written consent. 

We determine suitability for testing by learning about what medications you take, if you suffer from specific Axis I and/or IV disorders, or are unable to remain still for periods of time. If you have not had enough sleep, recently used drugs or alcohol, are experiencing pain, and if you are in advanced stages of pregnancy, this can affect your ability to be tested. 

Children ages 12 through 17 can be tested with parental permission. A 12 year old child may be tested if their “Mean Age Equivalency,” or SAS score, is at least 12 years of age and they have an IQ of 55 or above. 

All examinees have some type of general nervous tension. It is normal to feel nervous when going into a new situation. While a person’s heart and respiration rate may increase due to being nervous, this is to be expected and will not alter test results. 

During the pre-test phase, the examiner will explain all elements of the polygraph and review your test questions with you, prior to administering the examination. By this time, the truthful examinee will be a bit more relaxed; nervousness will not cause the innocent examinee to be shown deceptive.

In addition, unlike general nervous tension, an examinee’s reaction to deceptive responses is highly specific. An examiner mitigates a nervous response by reviewing the questions with the examinee and through an acquaintance or “practice test” prior to the exam.

Polygraph examinations are used to protect the public, to verify the truth, to identify the innocent, determine deception, and to help identify the guilty.

Polygraphs are most commonly used for criminal and civil matters, government and law enforcement pre-employment screening, homeland security, commercial theft investigations, to monitor convicted sex offenders being supervised by probation and parole, and while under treatment.

Private parties also request polygraph examinations to help resolve personal matters. Contrary to popular belief, polygraph results are admissible during criminal trials in many states, if stipulated. The states of New Mexico and Ohio have allowed Polygraph to be admitted routinely, even with the objection from an opposing party. 

The Supreme Court has left it up to individual jurisdictions to allow or disallow the use of polygraph examinations. There are only four (4) states that have a total ban on admitting polygraph results. Twenty three (23) states allow polygraph if both the plaintiff and the defendant have agreed (stipulated) that the results of the test will be admissible prior to the examination being conducted. They are admitted more frequently in civil trials than criminal trials. 

It is critical that your polygraph examination be performed by a certified examiner. Anyone conducting these tests in Nevada must meet stringent licensing requirements. All tests are administered by James Hannah, a licensed and board certified examiner. LVPI is a licensed and insured Nevada polygraph and private investigation company. PILB License #1066 in Nevada.

For more details on admissibility and case citations for each state, visit: www.polygraph.org Source: American Polygraph Association.