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What is a Polygraph?

A polygraph test, commonly known as a lie detector test, is a scientific test that collects physiological data from a person with the purpose of identifying reactions associated with dishonesty or deception. At least three systems in the human body are recorded during a polygraph examination.

Respiratory activity is monitored by placing rubber tubes across the examinee’s upper and lower chest. Electro-dermal activity is recorded by placing two small attachments on two fingers of one hand. Cardiovascular activity (changes in blood volume activity, not your blood pressure) is monitored by a blood pressure cuff.

The lie detector test/ polygraph exam is able to record physiological changes in your body when you lie and when you tell the truth. These changes, when interpreted by a professional polygraph examiner, are supporting evidence of truth or deception.

Who uses the polygraph?

The four sectors that use the polygraph include law enforcement agencies, the legal community, government agencies, and the private sector. They are further described as follows:

  1. Law Enforcement Agencies

    • Federal law enforcement agencies, state law enforcement agencies, and local law enforcement agencies such as police and sheriff's departments.

  2. Legal Community

    • U.S. Attorney Offices, District Attorney Offices, Public Defender Offices, defense attorneys, Parole & Probation Departments.

    • The court systems in cooperation with probation and parole officers and therapists to monitor convicted sex offenders.

    • Attorneys in civil litigation.

  3. Government Agencies

    • Department of Defense Agencies

    • Agencies in the Intelligence Community

  4. Private Sector

    • Companies and corporations under the restrictions and limitations of the Employee Polygraph Protection Act of 1988 (EPPA).

    • Private citizens in matters not involving the legal or criminal justice system.

What is the scope of test questions?

In a law enforcement preemployment polygraph examination, the questions include, but are not limited to, job related inquiries as the theft from previous employers, falsification of information on the job applications, the use of illegal drugs, and criminal activities. The test questions may be 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 specific issue polygraph examination the relevant questions focus on the particular act under investigation.

Who gets the test 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 that requested the examination, and others as may be required by law.

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