A "Voice Stress Analyzer" (VSA) is a device having the same basic purpose as the better known polygraph. Both of these devices seek to detect the presence or absence of stress on the part of a subject while being questioned about some relevant matter of concern to the questioner. The stress which a subject feels when he responds untruthfully to a question of importance to him produces certain involuntary physiological responses which the subject cannot readily control. The responses which the polygraph seeks to detect involve changes in his blood pressure, pulse rate, respiration rate, and the electrical resistance of his skin (e.g., due to sweat formation). The response which the VSA seeks to detect involves certain changes in the musculature of the throat and vocal chords. These changes produce an involuntary and essentially instantaneous change in the human voice which is inaudible to the human ear but which can be detected and measured electronically. Since the VSA system requires only the recording of a subject's speech, it is much simpler to apply than the polygraph with its many physical attachments to the human body. Consequently, VSA development has been vigorously pursued, starting with major efforts in the 1970's by the U. S. Army, and proceeding up to today's computerized versions capable of being operated from ordinary laptop computers. VSA systems are rapidly replacing existing polygraph systems in law enforcement and investigative agencies all across the country.
There are two major companies presently manufacturing and selling VSA equipment and offering training classes for examiners. Both of these companies maintain a web presence, from which a great deal of additional information can be gleaned concerning VSA theory, history, validation testing, and of course details of each company's operations. The first is the National Institute for Truth Verification (NITV), which calls its product the Computerized Voice Stress Analyzer (CVSA). Its website is at cvsa1.com. NITV has made a policy decision to sell their product only to law enforcement and certain other governmental agencies, so their product is unavailable for TIP system purposes. The second company is Truth and Detection Technologies, LLC (TDT), whose website is at tdtvsa.com. The company sells its product to police and governmental agencies, but also to private entities such as private investigators and corporations. TDT has therefore been selected for the TIP system's purposes, and considerable development work has been undertaken with TDT personnel to work out the mechanics for using their system.
Formal training in the interpretation of VSA output charts is mandatory, and an apprenticeship under the guiding hand of an experienced examiner is one of the more foolproof ways of attaining professional competence and confidence. For TIP purposes, only such experienced examiners, certified by TDT as successfully trained to perform such interpretation, will be used to examine the test records generated by TIP operations. These examiners will constitute the TIP "Certified Examiner Corps" (CEC) discussed on the TIP Structure page. Such expertise is not needed, however, by STIP Voting Members, who will be responsible for meeting with the subjects to be tested and administering the highly standard tests.
The audio files from the tests will always be
transmitted to two independent examiners. To protect the interests of a
political candidate, he will be adjudged to fail the test only if both
examiners diagnose the response to a given relevant question to be “Deception
Indicated”. However, to protect the interests of the TIP system, if
the subject being tested is a candidate TIP Voting Member, he will be adjudged
to fail the test if either examiner diagnoses the response to any
relevant question to be “Deception Indicated”.