voice stress test vs polygraph

How Accurate Is Voice Stress Analysis Test?

The McQuiston-Ford algorithm used for Voice Stress Analysis is reliably accurate. The recorded "micro tremors" in a person’s voice are converted via the algorithm into a scorable voice gram. The discrepancy in researched accuracy may result from incorrectly trained or non-trained persons utilizing the technology incorrectly. This is evident by some Polygraphists trying to "test" VSA technology without having received accredited training in the use thereof. However, a properly trained analyst and the latest equipment make the voice stress analysis test accurate.

Most 'polygraph only' associations have disputed the accuracy of VSA, although many accredited polygraphists have trained in the use of VSA and use VSA to good effect. The traditional analysis and scoring of voice-grams by means of assigning 'percentages' is clumsy and unreliable.

In 2005, Clifton Coetzee (Polygraph & VSA Instructor) devised a scoring method for voice grams incorporating the 'UTAH 7 Point' scoring system, as used by modern day polygraphists. Reactive or Responsive patterns are assigned a weighting of +3 to -3.



The use of CQT testing protocols developed by John Reid and Cleve Backster are used for greater reliability of VSA results. It is important that VSA examiners be skilled in the use of enforced, timed pauses between stimulus (question) and response (answer). As in the polygraph situation, the Flight or Fight syndrome has an onset delay, which must be considered by examiners to achieve reliable results.

The American Polygraph Association's website lists conclusions from multiple "university-grade studies" into the accuracy of voice stress analysis as a means of detecting the subject's truthfulness. All cast doubt on the validity of the results of such tests; many describe the results as no better than chance. This is to be expected of polygraph examiners, as they fight for the same business as voice analysts. The term "university-grade" is, in itself, meaningless. While several articles come from peer reviewed journals, many others are research reports to or by government agencies which generally have no peer-review process. It should be noted that prior to an APA Annual Convention in 2000, many APA Polygraph Instructors were teaching VSA alongside polygraph. It might be that the huge success of VSA was perceived as a threat to the polygraph industry, which incidentally is a source of funding to the APA. Want to know additional, sign up for at computer voice stress analysis accuracy.

How Accurate Is Voice Stress Analysis Test? Voice lie detection, following a paralinguistic pre-test interview, is very accurate. The figures most often cited are in the 95% - 98% range. Accordingly, that this technology is rapidly replacing the polygraph at many law enforcement agencies. There are several independent and unbiased studies conducted regarding the accuracy of voice stress analysis. Each of them show the high accuracy of the voice stress analysis lie detector tests.

Following the 9/11 attack on America, Congress provided President Bush with The Airport Security Federalization Act of 2001, which he signed into law. This includes the provision that airports will “provide for the use of Voice Stress Analysis or other technologies to prevent a person who might pose a danger to air safety from boarding the aircraft…”. Congress and this provision further legitimized the use of voice stress analysis as a means of truth verification. No other type of lie-detection has received such a strong endorsement.

Comparing the two types of lie-detection: Some have compared polygraph as being like old fashioned wired telephone lines and voice stress analysis as being like modern digital telephone service. Many states have enacted legislation regulating the use of voice lie detection on persons without their express consent in advance, yet even further endorsing the validity of VSA.