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Assessing the Validity of Voice Stress Analysis Tools in a Jail Setting

NCJ Number
Date Published
June 2007
127 pages
This study tested the validity and reliability of two popular voice stress analysis (VSA) programs (LVA and CVSA) in a "real world" setting, i.e., arrestees' deception about recent drug use.
The assessment found that the two programs were unable to detect deception about recent drug use at a rate any better than chance. The data also showed poor reliability for both VSA products when expert and novice interpretations of the output were compared. Correlations between novices and experts ranged from 0.11 to 0.52, depending on the drug in question. Another finding was that arrestees in this study were significantly less likely to be deceptive about recent drug use than arrestees in a non-VSA research project that used the same protocol. This finding supports the "bogus pipeline" effect, i.e., that truthfulness in self-report studies increases when subjects are convinced that questioners have an accurate "pipeline" that can detect deception. The researchers recommend further testing of VSA devices under various testing protocols. Questions about recent drug use were asked of a random sample of male arrestees in a county jail. Their responses and the VSA output were compared to a subsequent urinalysis in order to determine whether the VSA programs could detect deception. The sample was from the Oklahoma County Detention Center during the months of February and March 2006. The voluntary confidential interviews were conducted only with arrestees who had been in the detention facility for fewer than 48 hours. The sample selected during the high volume time was referred to as "flow" (five men per day), and the arrestees from the remaining hours of the day were referred to as "stock" (seven men per day). 44 tables, 18 figures, and 55 references

Date Published: June 1, 2007