The CVSA is more that a 98% accuracy rate based on scientific field and lab studies. The test is simple! The examiner asks a series of questions, and the person speaks into a microphone.
The CVSA computer displays and analyzes each voice pattern to detect deceptive reactions.
The CVSA exam takes about one hour to complete, where the old fashion "4 wires attached to body" polygraph, aka lie detector examinations, take roughly two hours to complete.
The CVSA exam takes about one hour to complete, where the lie detector aka polygraph examinations take roughly two hours to complete.
Computer Voice Stress Analyzer
Polygraph expert shows how to beat a lie detector test
No wires are connected to your body; only a microphone is used to capture a voice response!
The Computer Voice Stress Analyzer (CVSA) only uses a microphone that is plugged into the computer to analyze the person's responses.
As the individual speaks, the computer displays and numbers each voice pattern and saves each chart to a file.
The CVSA automatically analyzes the recorded yes or no responses to questions and detects deceptive or truthful reactions.
Unlike the the standard lie detector aka polygraph examinations, drugs don't affect the results of the CVSA exam, and there are no known countermeasures that will cause the typical "inconclusive" results associated with the polygraph.
A Voice Scanner CVSA lie detector test can be administered in the comfort of your home, office or via telephone.
The CVSA is effective in all investigative situations, such as homicides, sex crimes, theft, robberies, white-collar crimes, internal affairs investigations, pre-employment examinations for background investigators, as well as infidelity matters.
Embraced by the Department of Corrections, the system has also proven itself to be a very reliable investigative tool for verifying the statements of witnesses, the denials of suspects, and the validity of allegations made against police officers.
The CVSA Polygraph "no wires attached" exam!
Voice “Micro tremors” are tiny frequency modulations in the human voice. When a test subject is lying, the autonomic (involuntary) nervous system causes an inaudible increase in the micro tremors’ frequency.
The CVSA detects, measures, and displays changes in voice frequency.
A state-of-the-art computer then processes these changes and graphically displays a picture of the voice patterns. The CVSA is restricted to “yes” and “no” answers.
Our CVSA Senior Examiner is certified and current since 2006 having conducted over 300 law enforcement pre-employment CVSA exams in accordance with NITV and NACVSA guidelines.
Mr. Bennigson is retired from the Vallejo Police Department (California) after 35 years in Law Enforcement. He started his law enforcement career with the Tiburon Police Department in 1979 before transferring to the Vallejo PD in 1988.
In his career, Mr. Bennigson was a police officer, detective, FTO (Field Training Officer), Corporal, Sergeant, hostage negotiator, and traffic motor officer. While working investigations with Vallejo Police Department, Harry became a CVSA examiner in 1995.
Mr. Bennigson has conducted well over 1,000 examinations, ranging from fraud to homicide. After retiring from Vallejo PD, He worked in retirement with the UC Berkeley Police Department as a peace officer, and detective for six years. While at UCBPD, he implemented CVSA procedures and conducted examinations.
He solved two (2) criminal cold cases, obtained confessions and cleared individuals accused of crimes. He organized and planned recertification courses for all CVSA examiners throughout west coast.
Mr. Bennigson works closely with several private attorneys and police departments for pre-employment, criminal and civil CVSA exams.
Additionally, Mr. Bennigson meets with and conducts examinations for families and individuals in need of the truth.
- Vice President – Western Association of CVSA
- President – Pacific Association of CVSA
- Membership Chairman NACVSA (National Association of CVSA)
As President of the CVSA association and continuing board member, Mr. Bennigson has met and developed a good working relationship with many law enforcement officials and department heads. He has personally met and successfully negotiated with State Legislators to lobby for the CVSA.
CVSA Examiner & Instructor:
- Certified CVSA Examiner
- CVSA Law Enforcement instructor
- Good conduct medal
- Life saving medal
- Nominated for medal of courage
Synopsis of CVSA Study
Criminalistics and Court Expertise
2012 Annual Edition, Number 57
James L. Chapman, Professor Emeritus
Former Director of Forensic Crime Laboratory
State University of New York at Corning, NY USA
Scientific Consultant, Research Analyst
FIELD EVALUATION OF EFFECTIVENESS OF VSA
(VOICE STRESS ANALYSIS) TECHNOLOGY
IN A US CRIMINAL JUSTICE SETTING
This field study of criminal suspects and persons of interest is based upon actual CVSA examinations conducted by Prof. James Chapman over an 18-year period. The study resulted in an accuracy rate of 99.69%, a precision rate of 99.67% and a verified confession rate of 96.4%.
The total inventory of CVSA cases submitted, which exceeded 3,000, was culled
for cases that met the following criteria:
• A confession was a potential outcome
• There was no involvement with veracity testing of previous statements
• No employment clearance was involved
• The case was not used as confirmation of prior witness
• The facts of the case were such that responses could be verified by
means of CVSA follow-up questioning
After excluding cases that did not meet all of the above criteria, the criminal cases remaining for study in which legally admissible confessions were possible totaled 2,109. A total of 236 cases, involving 329 specific crimes (“Confession Possibilities”), were randomly selected.
These crimes included, but were not limited to: multiple homicides, corporate
theft, organized crime, contract murders, sexual abuse of children, and arson for
The subjects examined represented a wide spectrum, from people with no
criminal history to those with previous arrest/conviction records, and included
both males and females.
The socio-economic strata ran the gamut from wealthy, well-educated - 1 - Synopsis of CVSA Study professionals to indigents. The livelihood of those within the study group ranged from elected public officials to professional criminals, such as organized crime hit-men.
Of the cases studied, 91% represented criminal investigations in which legal
authorities had reached an investigative impasse. In other words, after following
standard investigative procedures, investigators had been unable to reach a firm conclusion as to guilt or innocence.
Each subject named in the “Confession Possibility” list was individually
interviewed by the CVSA examiner, with two goals in mind:
• To exonerate the innocent or identify the guilty, and
• To obtain legally valid and independently verifiable confessions from
those subjects who were unable to clear the CVSA process.
Each interview was conducted according to a standard protocol in which
the wording of the interview, but not the methodology, was adapted on-site
to each specific case. In each case, the CVSA procedure used by the examiner
consisted of the following six steps:
1. The CVSA examiner was briefed by the requesting authorities in order
to become familiar with the circumstances of each case.
2. A pre-test interview with the subject was conducted.
3. The initial test questions were formulated and presented to the
subject. Examinations contained from 9 to 31 questions, consisting of
relevant, irrelevant, and control questions for which the subject provided
“yes” or “no” answers.
4. The fourth step included processing the responses with the CVSA
instrument, after which the resulting CVSA charts were analyzed and
interpreted by the examiner.
5. If stress patterns associated with specific relevant questions (those
questions pertinent to the crime) were observed by the examiner, an
opportunity was given for the subject to provide additional
clarification regarding the stress.
Prior to the reexamination, questions were reformulated by the examiner to
evaluate the veracity of the explanations offered by the subject. This procedure
was repeated until all necessary questions had received responses which
displayed no stress reaction or until the remaining stress reactions could not be
eliminated by the explanation or the re-questioning.
6. The final step of the process was to provide a conclusion regarding the
outcome of the CVSA examination. If the relevant questions produced
a “No Stress” chart, the - 2 - Synopsis of CVSA Study subject was “cleared”
by the CVSA procedure. This information was then turned over to the
agency requesting the examination.
If a confession was made by the subject during the CVSA examination, the
examiner would ask the subject to support his/her confession by verifying
details or by providing further details concerning the events under investigation.
Further, if a confession occurred, the subject was asked to provide a written
Another CVSA examination would then be conducted to validate the accuracy
of the written statement. If no confession occurred, the examiner reported the
findings to the agency requesting the CVSA examination, such that the information could guide further investigation.
Of the 329 confession possibilities in this study, 92.1% of the CVSA examinations
produced a “Stress Indicated” result, and 89% of those resulted in validated
confessions. Most notably, in 96.4% of interviews conducted, where the
CVSA indicated stress, suspects made self-incriminating confessions.
The results of this study clearly establish that CVSA is a useful tool in obtaining
valid confessions, and that the likelihood of obtaining valid confessions increases based upon whether or not stress is present for relevant crime issues.
In each of the 236 cases in the study, which included 329 confession possibilities,
a trained and experienced CVSA examiner used well-established CVSA protocols resulting in legally admissible confessions and the acquisition of additional supporting evidence from suspects and/or persons of interest.
It is interesting to note that current scientific research reveals only 20-50% of
police interviews/interrogations result in valid confessions. A 96.4% verified
confession rate is phenomenally high compared to the 20-50% rate currently
achieved by police. Further, during this study the CVSA had a negligible error
rate, with a False Negative rate of 0% and a False Positive rate of 0.33%.
More importantly, this study substantiates the CVSA is a useful and
predictive decision support tool for separating the innocent from the
guilty, and conclusively demonstrates the CVSA’s ability to discriminate
stress from no-stress in the human voice.
In one case of Grand Larceny 20 individuals were considered suspects. Of
the 20 CVSA examinations conducted for this case, 19 resulted in a finding
of “No Stress Indicated,” while only one produced a “Stress Indicated”
finding – which resulted in a confession.
CVSA demonstrated its capability to accurately identifying the 19 innocent
individuals from the one who was guilty, far surpassing a “chance” rate of
accuracy. The probability of 20 successful evaluations of this type is less
than 1 in 1,000,000.
End of Chapman Study.
Note: The CVSA exam takes about one hour to complete, where the lie detector aka polygraph examinations take roughly two hours to complete.
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