I am amazed at the amount of comments from people that know very little or nothing about polygraph or CVSA and propitiate myths, and outright falsehoods.
I have been a polygraph examiner for over three decade and have administered pre-employment, specific issue, criminal, attorney, personal, as well as post-conviction sex offender examinations.
Before we accept the self-endorsements of the manufacturer, it is best that we first look at what scientists have to say.
Below is a list of the university-grade research studies that have investigated voice stress as a deception detection approach. Some studies looked at the CVSA device in particular, while others investigated whether voice stress analysis in general could be used to detect stress or deception. Copies of these studies can be obtained at many university libraries.
Brenner, M., Branscomb, H., & Schwartz, G. E. (1979). Psychological stress evaluator: Two tests of a vocal measure. Psychophysiology, 16(4), 351-357.
Conclusion: "Validity of the analysis for practical lie detection is questionable"
Cestaro, V.L. (1995). A Comparison Between Decision Accuracy Rates Obtained Using the Polygraph Instrument and the Computer Voice Stress Analyzer (CVSA) in the Absence of Jeopardy. (DoDPI95-R-0002). Fort McClellan, AL: Department of Defense Polygraph Institute.
Conclusion: Accuracy was not significantly greater than chance for the CVSA.
DoDPI Research Division Staff, Meyerhoff, J.L., Saviolakis, G.A., Koenig M.L., & Yourick, D.L. (In press). Physiological and Biochemical Measures of Stress Compared to Voice Stress Analysis Using the Computer Voice Stress Analyzer (CVSA). (DoDPI01-R-0001). Department of Defense Polygraph Institute.
Conclusion: Direct test of the CVSA against medical markers for stress (blood pressure, plasma ACTH, salivary cortisol) found that CVSA examiners could not detect known stress. This project was a collaborative effort with Walter Reed Army Institute of Research.
Fuller, B.F. (1984). Reliability and validity of an interval measure of vocal stress. Psychological Medicine, 14(1), 159-166
Conclusion: Validity of voice stress measures was poor.
Janniro, M. J., & Cestaro, V. L. (1996). Effectiveness of Detection of Deception Examinations Using the Computer Voice Stress Analyzer. (DoDPI95-P-0016). Fort McClellan, AL : Department of Defense Polygraph Institute.
DTIC AD Number A318986.
Conclusion: Chance-level detection of deception using the CVSA as a voice stress device.
Hollien, H., Geison, L., & Hicks, J. W., Jr. (1987). Voice stress analysis and lie detection. Journal of Forensic Sciences, 32(2), 405-418.
Conclusions: Chance-level detection of stress. Chance-level detection of lies.
Horvath, F. S. (1978). An experimental comparison of the psychological stress evaluator and the galvanic skin response in detection of deception. Journal of Applied Psychology, 63(3), 338-344.
Conclusion: Chance-level detection of deception.
Horvath, F. S. (1979). Effect of different motivational instructions on detection of deception with the psychological stress evaluator and the galvanic skin response. Journal of Applied Psychology, 64(3, June), 323-330.
Conclusion: Voice stress did not detect deception greater than chance.
Kubis, J. F. (1973). Comparison of Voice Analysis and Polygraph As Lie Detection Procedures. (Technical Report No. LWL-CR-03B70, Contract DAAD05-72-C-0217). Aberdeen Proving Ground, MD: U.S. Army Land Warfare Laboratory.
Conclusion: Chance-level detection of deception for voice analysis.
Lynch, B. E., & Henry, D. R. (1979). A validity study of the psychological stress evaluator. Canadian Journal of Behavioural Science, 11(1), 89-94.
Conclusion: Chance level detection of stress using the voice.
O'Hair, D., Cody, M. J., & Behnke, R. R. (1985). Communication apprehension and vocal stress as indices of deception. The Western Journal of Speech Communication, 49, 286-300.
Conclusions: Only one subgroup showed a detection rate significantly better than chance, and it did so by the thinnest of margins. Use of questionable statistical methods in this study suggests the modest positive findings would not be replicated in other research. See next citation.
O'Hair, D., Cody, M. J., Wang, S., & Chao, E. Y. (1990). Vocal stress and deception detection among Chinese. Communication Quarterly, 38(2, Spring), 158ff.
Conclusion: Partial replication of above study. Vocal scores were not related to deception.
Suzuki, A., Watanabe, S., Takeno, Y., Kosugi, T., & Kasuya, T. (1973). Possibility of detecting deception by voice analysis. Reports of the National Research Institute of Police Science, 26(1, February), 62-66.
Conclusion: Voice measures were not reliable or useful.
Timm, H. W. (1983). The efficacy of the psychological stress evaluator in detecting deception. Journal of Police Science and Administration, 11(1), 62-68.
Conclusion: Chance-level detection of deception.
Waln, R. F., & Downey, R. G. (1987). Voice stress analysis: Use of telephone recordings. Journal of Business and Psychology , 1(4), 379-389.
Conclusions: Voice stress methodology did not show sufficient reliability to warrant its use as a selection procedure for employment.
If anyone has any information concerning additional statistically significant independent studies concerning the accuracy of CVSA, please post them for review.
You can go to the American Polygraph Association web site for further information.
I completed the "whole" week long CVSA “training session†and REFUSE to use the CVSA, unless it is used in conjunction with the polygraph, as I have found it totally useless on its own.
The training for CVSA was (when I went through the course) a one week class (40 hours), as opposed to polygraph training which lasts between six to eight weeks, then a minimum of a six to twelve month internship under a licensed, approved sponsor. Annual continuing education is required by most states licensing polygraph examiners.
The polygraph should be used as an investigative tool, not the final determining factor in any situation. Think of it like an X-ray. How accurate is an x-ray, only as good as the doctor reading the results.
Concerning countermeasures, any properly trained examiner will identify them. If you are going to be truthful, why would you try to manipulate the examination? The individuals selling a “How to beat the polygraph†books are taking advantage of the uninformed, gullible people. Several of them sited in these forums, have been criminally prosecuted by the federal government (the biggest user of polygraph examinations).
For those who believe polygraph examinations are not admissible in court. Read the Supreme Court decision in Dalbert VS Dow Chemical 1999. The court held the federal rules of evidence, not the Frye ruling determines that the courts can consider the results at their discretion.
If you have additional questions, I will be more than happy to answer those which I can answer.
I have been a polygraph examiner for over three decade and have administered pre-employment, specific issue, criminal, attorney, personal, as well as post-conviction sex offender examinations.
Before we accept the self-endorsements of the manufacturer, it is best that we first look at what scientists have to say.
Below is a list of the university-grade research studies that have investigated voice stress as a deception detection approach. Some studies looked at the CVSA device in particular, while others investigated whether voice stress analysis in general could be used to detect stress or deception. Copies of these studies can be obtained at many university libraries.
Brenner, M., Branscomb, H., & Schwartz, G. E. (1979). Psychological stress evaluator: Two tests of a vocal measure. Psychophysiology, 16(4), 351-357.
Conclusion: "Validity of the analysis for practical lie detection is questionable"
Cestaro, V.L. (1995). A Comparison Between Decision Accuracy Rates Obtained Using the Polygraph Instrument and the Computer Voice Stress Analyzer (CVSA) in the Absence of Jeopardy. (DoDPI95-R-0002). Fort McClellan, AL: Department of Defense Polygraph Institute.
Conclusion: Accuracy was not significantly greater than chance for the CVSA.
DoDPI Research Division Staff, Meyerhoff, J.L., Saviolakis, G.A., Koenig M.L., & Yourick, D.L. (In press). Physiological and Biochemical Measures of Stress Compared to Voice Stress Analysis Using the Computer Voice Stress Analyzer (CVSA). (DoDPI01-R-0001). Department of Defense Polygraph Institute.
Conclusion: Direct test of the CVSA against medical markers for stress (blood pressure, plasma ACTH, salivary cortisol) found that CVSA examiners could not detect known stress. This project was a collaborative effort with Walter Reed Army Institute of Research.
Fuller, B.F. (1984). Reliability and validity of an interval measure of vocal stress. Psychological Medicine, 14(1), 159-166
Conclusion: Validity of voice stress measures was poor.
Janniro, M. J., & Cestaro, V. L. (1996). Effectiveness of Detection of Deception Examinations Using the Computer Voice Stress Analyzer. (DoDPI95-P-0016). Fort McClellan, AL : Department of Defense Polygraph Institute.
DTIC AD Number A318986.
Conclusion: Chance-level detection of deception using the CVSA as a voice stress device.
Hollien, H., Geison, L., & Hicks, J. W., Jr. (1987). Voice stress analysis and lie detection. Journal of Forensic Sciences, 32(2), 405-418.
Conclusions: Chance-level detection of stress. Chance-level detection of lies.
Horvath, F. S. (1978). An experimental comparison of the psychological stress evaluator and the galvanic skin response in detection of deception. Journal of Applied Psychology, 63(3), 338-344.
Conclusion: Chance-level detection of deception.
Horvath, F. S. (1979). Effect of different motivational instructions on detection of deception with the psychological stress evaluator and the galvanic skin response. Journal of Applied Psychology, 64(3, June), 323-330.
Conclusion: Voice stress did not detect deception greater than chance.
Kubis, J. F. (1973). Comparison of Voice Analysis and Polygraph As Lie Detection Procedures. (Technical Report No. LWL-CR-03B70, Contract DAAD05-72-C-0217). Aberdeen Proving Ground, MD: U.S. Army Land Warfare Laboratory.
Conclusion: Chance-level detection of deception for voice analysis.
Lynch, B. E., & Henry, D. R. (1979). A validity study of the psychological stress evaluator. Canadian Journal of Behavioural Science, 11(1), 89-94.
Conclusion: Chance level detection of stress using the voice.
O'Hair, D., Cody, M. J., & Behnke, R. R. (1985). Communication apprehension and vocal stress as indices of deception. The Western Journal of Speech Communication, 49, 286-300.
Conclusions: Only one subgroup showed a detection rate significantly better than chance, and it did so by the thinnest of margins. Use of questionable statistical methods in this study suggests the modest positive findings would not be replicated in other research. See next citation.
O'Hair, D., Cody, M. J., Wang, S., & Chao, E. Y. (1990). Vocal stress and deception detection among Chinese. Communication Quarterly, 38(2, Spring), 158ff.
Conclusion: Partial replication of above study. Vocal scores were not related to deception.
Suzuki, A., Watanabe, S., Takeno, Y., Kosugi, T., & Kasuya, T. (1973). Possibility of detecting deception by voice analysis. Reports of the National Research Institute of Police Science, 26(1, February), 62-66.
Conclusion: Voice measures were not reliable or useful.
Timm, H. W. (1983). The efficacy of the psychological stress evaluator in detecting deception. Journal of Police Science and Administration, 11(1), 62-68.
Conclusion: Chance-level detection of deception.
Waln, R. F., & Downey, R. G. (1987). Voice stress analysis: Use of telephone recordings. Journal of Business and Psychology , 1(4), 379-389.
Conclusions: Voice stress methodology did not show sufficient reliability to warrant its use as a selection procedure for employment.
If anyone has any information concerning additional statistically significant independent studies concerning the accuracy of CVSA, please post them for review.
You can go to the American Polygraph Association web site for further information.
I completed the "whole" week long CVSA “training session†and REFUSE to use the CVSA, unless it is used in conjunction with the polygraph, as I have found it totally useless on its own.
The training for CVSA was (when I went through the course) a one week class (40 hours), as opposed to polygraph training which lasts between six to eight weeks, then a minimum of a six to twelve month internship under a licensed, approved sponsor. Annual continuing education is required by most states licensing polygraph examiners.
The polygraph should be used as an investigative tool, not the final determining factor in any situation. Think of it like an X-ray. How accurate is an x-ray, only as good as the doctor reading the results.
Concerning countermeasures, any properly trained examiner will identify them. If you are going to be truthful, why would you try to manipulate the examination? The individuals selling a “How to beat the polygraph†books are taking advantage of the uninformed, gullible people. Several of them sited in these forums, have been criminally prosecuted by the federal government (the biggest user of polygraph examinations).
For those who believe polygraph examinations are not admissible in court. Read the Supreme Court decision in Dalbert VS Dow Chemical 1999. The court held the federal rules of evidence, not the Frye ruling determines that the courts can consider the results at their discretion.
If you have additional questions, I will be more than happy to answer those which I can answer.
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