Polygraph and Voice Stress Analysis: Trying to Find the Right Tool
The validity of the polygraph as a lie-detection device has been under fire for years. In 2003, the National Academy of Sciences
issued a report identifying major deficiencies in polygraph technology. The report and other analyses led to the research and development of potential alternatives to the polygraph; one technology
that emerged is voice stress analysis (VSA).
The National Institute of Justice funded a study to evaluate two of the most popular VSA software programs in a real-world
(that is, nonlaboratory) setting in which jeopardy—the threat of penalty—was present.
The study found that the average accuracy rate of these programs in detecting deception regarding drug use was approximately
50 percent—about as accurate as flipping a coin. But the research also found that subjects may be deterred from lying if they
think their responses can be "proven" false.
It remains to be seen, however, if any deterrence factor dissipates as word spreads about the accuracy rate of VSA software
programs. Prospective users of VSA should weigh all these factors, including that there may be an investigative, even if there
is no evidentiary, use for this technology.
 Committee to Review the Scientific Evidence on the Polygraph, National Research Council, The Polygraph and Lie Detection, Washington, DC: National Academies Press, 2003.
Date Created: March 17, 2008