Voice Stress Analysis: Only 15 Percent of Lies About Drug Use Detected in Field Test

"Law enforcement agencies across the country have invested millions of dollars in voice stress analysis (VSA) software programs.[1] One crucial question, however, remains unanswered:

Does VSA actually work?

According to a recent study funded by the National Institute of Justice (NIJ), two of the most popular VSA programs in use by police departments across the country are no better than flipping a coin when it comes to detecting deception regarding recent drug use. The study's findings also noted, however, that the mere presence of a VSA program during an interrogation may deter a respondent from giving a false answer.

VSA manufacturers tout the technology as a way for law enforcers to accurately, cheaply, and efficiently determine whether a person is lying by analyzing changes in their voice patterns. Indeed, according to one manufacturer, more than 1,400 law enforcement agencies in the United States use its product.[2] But few studies have been conducted on the effectiveness of VSA software in general, and until now, none of these tested VSA in the field—that is, in a real-world environment such as a jail. Therefore, to help determine whether VSA is a reliable technology, NIJ funded a field evaluation of two programs: Computer Voice Stress Analyzer® (CVSA®)[3] and Layered Voice AnalysisTM (LVA)".

by Kelly R. Damphousse, Ph.D.

Comparasions of Voice Stress with computerised polygraph measures: see attached PDF: