What Is VSA?
VSA (Voice Stress Analysis) is a polygraph testing technique. A technology that claims to detect deception by analysing micro-tremors in the human voice. Not a polygraph technique. Not validated by the APA or any recognised scientific body. Multiple peer-reviewed studies show VSA performs no better than chance at detecting deception. Examiners and consumers should be aware that VSA-based “lie detector” services are not legitimate polygraph examinations.
How VSA Works in Practice
As a polygraph testing technique, VSA follows structured protocols for question presentation and physiological data collection. The technique is used within the broader framework of Psychophysiological Detection of Deception and must be administered by a trained, APA-member examiner following established Standards of Practice.
During a polygraph examination using this approach, the examiner collects physiological data across multiple channels — respiratory, electrodermal, cardiovascular, and movement — while presenting a structured sequence of relevant, comparison, and irrelevant questions. The examinee’s differential physiological responses to these question types form the basis for the diagnostic or screening opinion.
Scoring and Data Analysis
Results from examinations using this technique are analysed using validated Test Data Analysis">Test Data Analysis methods. These include manual numerical scoring systems (3-position or 7-position scales) and automated computerised scoring algorithms such as OSS-3, PolyScore, or ESS. The choice of scoring method affects the balance between sensitivity (detecting deception) and specificity (confirming truthfulness), as well as the Inconclusive Rate">inconclusive rate.
Related Terms
Understanding VSA in context requires familiarity with several related polygraph concepts:
See also: Anti-Climax Dampening, Arther Technique, Accusatory Approach, Zone">Black Zone, Backster Zone Comparison Technique, Comparison Question.
Further Reading
For more information on polygraph terminology and the science of lie detection, explore the full Polygraph Glossary with over 250 defined terms. Visit the Polygraph Examiner Hub for professional resources, the research database for published polygraph studies, or learn how a polygraph works if you are preparing for an examination.
Key Takeaways
VSA is an important concept within the field of Psychophysiological Detection of Deception. Whether you are a polygraph examiner, student at an APA-accredited training programme, legal professional evaluating polygraph evidence, or a private individual preparing for a lie detector test, understanding this term and its relationship to other polygraph concepts will help you navigate the field with greater confidence and knowledge.
The science of polygraph testing has evolved significantly over more than 100 years, from the early work of William Moulton Marston and Leonarde Keeler to today’s digital instruments and validated scoring algorithms. Every term in this glossary represents a piece of that scientific and professional heritage. For a comprehensive overview, visit the Polygraph Examiner Hub or use our examiner selection guide to find a certified examiner near you.