Q: How accurate are polygraph or “lie detector” results?
A: Results are normally between 90 to 95% accurate, depending on a few key factors like how direct the questions are and how long ago the incident occurred. The American Polygraph Association, which sets standards for testing, says that polygraphs are “highly accurate,” citing an accuracy rate above 90 percent when done properly. However the instrument itself is simply a recording device, and does not say whether or not a subject is lying. It all comes down to the trained examiner to properly develop a strategic line of questions, properly discuss the relevant questions along with the knowledge of the overt actions in question. Most of all be able to properly read the recorded physiological responses and identify reactions that are indicative to deception vs the baseline of each individual’s holistic reactions to non relative questions. So in essence, you may be able to beat the examiner, but not the instrument as it will accurately record your physiological responses to each question.
Q: How much time does the average polygraph exam take?
A: The average polygraph exam takes between 90 minutes and 3 hours. This includes gathering the facts, a pre-test interview, formulating the questions, and the actual exam, in which questions are asked at least three times. A post exam conversation can also be had to deliver the results to the requesting party, if they are present.
Q: How does a Polygraph Examination work?
A: Our examiners use computerized recording systems and software in accordance with American Polygraph Association standards. The recording instrument and questioning techniques are only used during the actual test of the polygraph examination.
A typical polygraph examination includes 3 phases:
• Pretest: The polygraph Examiner completes required paperwork and talks with the Examinee about the purpose of the test. During this period, the Examiner discusses the questions to be asked and familiarizes the Examinee with the testing procedure and explains how the instrument works. The Examiner may also give an acquaintance test in efforts to familiarize the Examinee with the testing procedures, and to acquire a baseline of the Examinee’s physiology.
• Chart collection phase: The Examiner administers the test and collects a number of polygraph charts to be analyzed and graded. The Examiner may stop the test at anytime if he sees that the Examinee may be trying to manipulate the physiological data, and at which time will advise against the manipulation.No examination with manipulations will be evaluated.
• Data analysis: The Examiner analyzes the charts and renders an opinion as to the truthfulness of the person taking the test. The Examiner, when appropriate, offers the Examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. The Examiner may also run another break out test after the original collection of charts, if the Examinee shows indication of deception, and provides more information as to why and providing the opportunity to explain their physiological reactions.
The Examiner may use a series of techniques to detect truth or deception that may include a series of relevant and comparison questions regarding an overt action. As well as guilty knowledge questions, which may involve developing a multiple-choice test with items concerning knowledge that only a guilty subject could have.
Q. Who uses the polygraph?
A. • Law Enforcement Agencies – Federal Law Enforcement Agencies, State Law Enforcement Agencies, and Local Law Enforcement Agencies such as Police and Sheriff’s Departments.
• Legal Community – U.S. Attorney Offices, District Attorney Offices, Public Defender Offices, Defense Attorneys, Parole & Probation Departments, Treatment and Therapy providers.
• 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 such as fidelity testing, attorneys in civil litigation.
Are Polygraph Examinations Admissible in Court?
A: The United States Supreme Court leaves the question of the admissibility of lie detector test evidence up to individual jurisdictions. Some courts allow lie detector evidence in certain proceedings or only when both parties agree to its admissibility. Other jurisdictions do not allow any lie detector evidence. The states that sometimes allow polygraph tests as evidence in criminal case include but not limited to the following states:
- Alabama
- Arizona
- Arkansas
- California
- Delaware
- Georgia
- Idaho
- Indiana
- Iowa
- Kansas
- Nevada
- New Jersey
- New Mexico
- North Dakota
- Ohio
- Utah
- Washington
- Wyoming
In many other states, prosecuting attorneys will consider polygraph results for or against prosecution.