Q: What is a polygraph?
A: The term polygraph is a term which means "many writings." The polygraph, commonly known as a "lie detector," records physiological responses to stimuli (questions) in the following channels: thoracic and abdominal respiratory acitivity, electrodermal activity, and cardiograph activity.
Additional research is currently being conducted on P300 brain waves (known as "brain fingerprinting"), functional magnetic resonance imaging (fMRI), skin surface temperature using high definition thermal imaging devices and laser doppler of the carotid artery.
Q: How valid/accurate is polygraph? A: According to peer-reviewed, scientific research polygraph validity/accuracy rates range from a low of approximately 80% (laboratory studies) to a high of approximately 90% (field studies) range. While no scientific test is perfect, when administered by a properly trained, experienced and certified examiner polygraph has a very high degree of accuracy. For more information on polygraph validity research please visit http://www.polygraph.org/validity-research
Q: What about Computerized Voice Stress Analyzers (CVSA)...aren't they better than a polygraph?
A: Bottom line, study after study has proven that CVSA has absolutely no scientific validity:
Excerpt from the summary report of the University of Oklahoma on the Validity of Voice Stress Analysis
March 31, 2007
"The important finding is that the VSA programs do not appear to provide any probability of detecting deception than chance."
In other words, you get the same results with CVSA as flipping a coin!
Excerpt from court testimony by CVSA founder:
"NITV acknowledges that the CVSA is not capable of lie detection and specifically cautions its users regarding proper use of the device."
Unfortunately, because CVSA is much cheaper than polygraph, many local police departments continue to rely upon the CVSA over polygraph even though the CVSA founder admits it doesn't work!
Q: I heard a polygraph can be beat. Is this true?
A: While a number of websites purport that polygraph can be fooled by the use of simple countermeasure techniques, the fact is that all federally trained/certified polygraph examiners undergo intensive training on countermeasure recognition. Use of countermeasures simply invalidates the test and therefore no determination of truth or decepton can be made when countermeasures are employed.
Q: What qualifications should I look for before retaining the services of a polygraph examiner?
A: Graduation from an American Polygraph Association accredited polygraph school (for a full list, please visit http://www.polygraph.org/content/apa-accredited-polygraph-schools ), a minimum of ten years experience in the field, licensed in a licensing state (Maryland currently has no provison for licensing polygraph examiners; however, Veracity Assessment Services, LLC holds a Virginia polygraph license), proof of professional liability insurance, and full membership in the American Polygraph Association.
Q: How many questions can be asked?
A: A properly constructed polygraph exam can only focus on one central issue per exam. While there are a number of questions asked during the actual intest phase of the exam, they are all formulated to resolve one cental issue. With the exception of screeing formats, different issues cannot be mixed on the same examination.
Q: How long does the test take?
A: All polygraph examinations are formulated to resolve unique situations. In most cases, a propelry conducted polygraph examination will take a minimum of 1.5 - 4 hours depending on the complexity of the issue to be resolved.
Q: How much does a polygraph test cost?
A: The cost of a properly conducted polygraph examination is dependent upon the complexity of the issue to be resolved, the training, experience and reputation of the examiner. Most private polygraph examiners charge anywhere from a low of $400 (domestic issue) up to $1500 (criminal issue/defense attorney) per exam. The cost of an exam takes into account overhead, polygraph equipment, insurance, membership in professional organizations, required annual training, case preparation and travel to the exam location.
Q: But isn't polygraph inadmissible in a court of law?
A: Not always true. A number of federal circuits and states allow polygraph results into evidence under stipulation. For more information on the most currentl legal issues surrounding polygraph, please visit http://www.polygraph.org/faq
