Polygraph Examination Process

Polygraph Instrument Is A Scientific Instrument

The polygraph is a scientific instrument used to measure how a person’s body responds to various questions in a controlled setting. The test is based on the theory that when telling a lie, the individual being examined, known as the examinee, will fear being caught in the lie and his or her body will react to reflect that fear. Polygraph Science Center examiners use computerized instruments.

The American Polygraph Association has consistently supported licensing efforts throughout the country. The APA encourages efforts to establish proper qualifications for polygraph examiners and criteria for testing procedures.

The polygraph consists of three phases: the pretest interview, the test and the post-test phase. The latter may include the examiner questioning the examinee and his or her responses to the questions. Before beginning the first phase in the polygraph process, the Polygraph Science Center examiner will gather information about the case from the investigator. Collecting this information allows the examiner to create appropriate questions for the actual examination. Having created his questionnaire, the examiner is ready for the pretest interview.

Pre-test Preparation

To begin the pretest interview, the examiner introduces himself or herself to the person being examined and describes what will happen during the polygraph examination.

The Polygraph Science Center examiner then gets the individual to explain his or her version of what happened and then discusses the questions that will be asked during the polygraph. Once the examiner has discussed this information with the examinee, phase two of the polygraph begins. We use an acquaintance test to allow the examinee to experience the process without duress. This also allows the examiner to adapt the instrumentation to the individual’s physiology.

Testing Phase

To establish how an individual would physically respond when telling the truth or lying, the polygraph examination includes questions that develop baseline readings for what the Polygraph Science Center examiners call “tonic.” For example, a question targeting a known truth for a 35-year-old male examinee might be “Are you 35 years old?” to which the examinee would truthfully answer “yes”.

The character questions are ones to which the examinee will likely have reservations because the truth may be less personally or socially acceptable. For example, an examinee may be uncomfortable with “Have you ever lied to someone who trusted you?”

Both questions together allow the Polygraph Science Center examiner to record the blood pressure, pulse, perspiration, and respiration of the examinee, and then observe and compare those responses to the results measured for questions regarding the crime or relevant issue. Within the relevant test, the examinee will face a variety of questions. All the questions require only a simple “yes” or “no” answer. Through most of these questions, the examiner is trying to measure the individual’s knowledge, participation and involvement in the incident under investigation. Deceptive answers are recognized by increases in perspiration, blood pressure and pulse and changes in breathing patterns. These are telltale signs of a lie.

What May NOT Legally Be Asked

Personal and intrusive questions have no place in a properly conducted polygraph examination. Many state licensing laws, the Employee Polygraph Protection Act, as well as the American Polygraph Association, prohibit non-related intrusive questions in the following areas:

  • religious beliefs or affiliations
  • beliefs or opinions regarding racial matters
  • political beliefs or affiliations
  • beliefs, affiliations or lawful activities regarding unions or labor organizations
  • sexual preferences or activities

In a specific issue polygraph examination of an evidentiary nature, the relevant questions focus on the particular act under investigation.

If the issue involves a sexual offense, or if a sensitive security matter is at stake, there may be documented exceptions to the preceding prohibitions.

Post-test Phase

When the Polygraph Science Center examiner finishes asking questions, while recording the response tracing with the polygraph instrument, he or she evaluates the results to find out whether the individual has been deceptive. If the polygraph examination results indicate that the examinee was telling the truth, the individual is thanked for participating in the test and leaves. But, if the examination results indicate that the individual appears to be deceptive, the examiner will begin the third phase of the test.

The questioning or interrogation, gives the examinee an opportunity to clarify, or it allows the Polygraph Science Center examiner to help the examinee overcome denial and to tell the truth. While acting in a professional and understanding manner, a skilled examiner may use effective questioning techniques to make the examinee comfortable with telling the truth. After all, that is the purpose of the entire process.

Security Screening for Sensitive Jobs

In a law enforcement pre-employment polygraph examination, the questions focus on such job related inquiries as the theft of money or merchandise from previous employers, falsification of information on the job applications, the use of illegal drugs and criminal activities. The test questions are limited in the time span they cover, and all are reviewed and discussed with the examinee during a pre-test interview before any polygraph testing is done. There are no surprise or trick questions in a properly administered examination. They are always reviewed by a Polygraph Science Center examiner.

Limiting the Margin of Error

While the polygraph technique is highly accurate, it is not infallible and errors do occur. Polygraph errors may be caused by the poorly skilled examiner’s failure to properly prepare the examinee for the examination, or by a misreading of the physiological data on the polygraph charts. Errors are usually referred to as either false positives or false negatives. A false positive occurs when a truthful examinee is reported as being deceptive; a false negative when a deceptive examinee is reported as truthful. Some research indicates that false negatives occur more frequently than false positives, other research studies show the opposite conclusion.

Since it is recognized that any error is damaging, Polygraph Science Center examiners utilize a variety of procedures to identify the presence of factors which may cause false responses, and to insure an unbiased review of the polygraph records.

These quality assurance procedures used by Polygraph Science Center include:

  • an assessment of the examinee’s emotional state
  • medical information about the examinee’s physical condition
  • specialized tests to identify the overly responsive examinee and to calm the overly nervous
  • stimulation questions to evaluate the examinee’s response capabilities
  • factual analysis of the case information
  • a pre-test interview and detailed review of the questions
  • quality control reviews by other Polygraph Science Center examiners.

If a polygraph examinee believes that an error has been made, there are several actions that may be taken including the following:

  1.  Request a second examination
  2. Retain an independent examiner for a second opinion
  3. File a complaint with a state licensing board
  4. File a complaint with the Department of Labor under EPPA
  5. File a request for the assistance of the American Polygraph Association

Exceptions To The Rule

The Employee Polygraph Protection Act of 1988 prohibits much, but not all pre-employment polygraph testing. Also most of the states make exceptions for testing of certain occupational groups. There are some exempted organizations that may do a pre-employment polygraph screen. However they must comply with other employment rules. Commonly exempted are law enforcement agencies, security firms and companies that manufacture, distribute or dispense drugs and controlled substances.

In addition to the Employee Polygraph Protection Act, to date there are 20 states and the District of Columbia which have enacted legislation designed to regulate an employer’s use of the polygraph. No state prohibits polygraph testing in all settings. A typical statute states:

“No employer may require a prospective or current employee to take a polygraph examination as a condition of employment or continued employment.”

There are exceptions that protect a business that has an internal problem. Testing of employees is permitted to solve an employer’s “economic loss.” Those exempted agencies also have more testing flexibility concerning incidents connected with their day-to-day operations. Examples of the categories are: police, fire, special security personnel, armored car personnel and those who handle drugs and narcotics.

EPPA does not affect testing for attorneys or local, state or federal agencies. See: PL 199 437. Final Rules in the Federal Register,56 (42). Monday, March 4 1991,29 CRF Part 801.

Confidentiality Of Results

According to the various state licensing laws and the American Polygraph Association’s Standards and Principles of Practice, polygraph results can be released only to authorized persons. Generally those individuals who can receive test results are the examinee, and anyone specifically designated in writing by the examinee, the person, firm, corporation or governmental agency which requested the examination, and others as may be required by due process of law.


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