The Truth About Voice Stress Technologies


New- Florida Study
Oklahoma Study

Learn the truth about the so-called "lie detector"

"Charlatanry In Forensic Speech Science"
 A problem to be taken seriously.

Eriksson & Lacerda 2007

The International Journal of Speech, Language and the Law

Click the above link to read the latest on
VSA, CVSA & LVSA accuracy

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.  These findings add to the growing literature on tests of voice stress analysis theory and devices.

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."

Excerpt from the report of the University of Florida on
 "Voice Stress Analyzer Instrumentation Evaluation"

February 26, 2006

The findings generated by this study led to the conclusion that neither the CVSA nor the LVA showed any sensitivity to the presence of deception or stress. Several analyses of subsets of the data were undertaken to explore any possibility that either system could perform under more controlled conditions, but no sensitivity was observed in any of these analyses (see the Technical Results section). These results are congruent with those observed in past surveys of research on voice stress analysis (National Research Council, 2003).


Recently many police departments have become enamored with the latest gadget for detecting lies:  voice stress analyzers.  They’re cheap, convenient, and have a high-tech look about them.  There are at least three manufacturers of these machines, but none of them can claim to have any research supporting their use.  Instead they have relied on selective personal testimonials on how they can be used to obtain confessions, while the routine failure of the device as a lie detector is overlooked.  Are confessions the same as validity?  Hardly.  For years cops used to get confessions from suspects with all kinds of lie detector ruses, like wiring a naïve suspect to a photocopier, or using the old Motorola radio in their squad cars that could change a red light to green when the mike button was pressed.  And, a phony ploy works only so long before people catch on.  Just how accurate are voice stress analyzers?  Let’s set aside for the moment what their salesmen have to say, and look at what the scientists have reported.

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If you have comments concerning voice stress analyzers join the discussion!


If the voice stress salesmen claim that there is no research, point them to the articles you'll find here on this site..

Warning to the Public

Have you lost a job opportunity with a law enforcement agency because you wrongly failed a voice stress analyzer test?  You may have a legal remedy.  Most large police agencies are governed by state or municipal civil service rules or laws, which make them also subject to the US government’s Equal Employment Opportunity Commission rule 29 CFR 1607, the Uniform Guidelines on Employee Selection Procedures (July 1, 1998).  According to the EEOC, all employee selection tools must meet minimum standards, including validation.  It is simply a matter of law that departments must use validated tools for hiring, such as the MMPI, CPI, polygraph, urinalysis, intelligence tests or others that have withstood independent scientific investigation.  They are specifically prohibited from using unvalidated methods.  The voice analyzer technology falls into the unvalidated category.  If you took a voice stress to get a law enforcement job, it is a violation of your rights under these EEOC provisions. Contact your attorney for more advice.

Click here for APA,  AAPP & DACA policy on voice stress    

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