Daytona Beach News-Journal Discredits Voice Stress Analysis

In a 28 April 2007 editorial cryptically titled, “Wired Policing Stresses Voices, More,” the Daytona Beach News-Journal skewers local law enforcement agencies’ reliance on voice stress analyzers:

As the urban legend goes, police interrogating a suspect put a colander on the suspect’s head, run wires from the colander to a copy machine, make a meaningless copy, look at it, then tell the suspect he’s lying. The suspect, of course, doesn’t know the whole thing is a hoax. Frightened by the amazing lie detector, he confesses.

The legend might as well be true. Local police agencies, including the Volusia County Sheriff’s Office and the Daytona Beach Police Department, use so-called “voice-stress analysis” as part of their interrogation techniques. The Flagler County Sheriff’s Office plans to use it as part of its job-interview process. A study by the Defense Department has concluded that such analysis is bunk — no more reliable than the colander trick. Nevertheless, police agencies spend thousands of dollars on the equipment and justify it as a legitimate part of police work. The Daytona Beach Police Department just spent $32,000 for the equipment.

It’s the best, the most reliable voice stress-analyzer out there,” said Lt. Gorgi Colon, who, with Sgt. Paul Barnett, was tasked by Daytona Beach Police Chief Mike Chitwood to research the technology. Gleaning the studies wasn’t part of the research. Calls were placed instead to the Volusia sheriff’s office and to the West Palm Beach company that manufactures the “analyzers” and dominates the field by aggressively marketing itself as the “world leader in voice-stress analysis.” As part of its marketing, the company trains individuals in agencies that buy the product.

The company’s name — the National Institute for Truth Verification — makes it sound like an academy. It isn’t. It’s a privately held company directed by Bill Endler, a retired Indiana police chief who spent four months interrogating suspects at Abu Ghraib prison in Iraq and in Baghdad’s Green Zone between October 2003 and January 2004. His contract there was not renewed, and the Pentagon, based on its own Department of Defense Polygraph Institute studies, distrusts the voice-stress technology. “In our evaluation,” Mitchell S. Sommers, an associate professor of psychology in Arts & Sciences at Washington University in St. Louis, told a university publication in 2004, “voice-stress analysis detected some instances of deception, but its ability to do so was consistently less than chance — you could have gotten better results by flipping a coin.” Sommers’ research was paid for by the Defense Department.

“What it boils down to,” Endler said, “is nothing more than a turf war. We are taking business away from them.” But the Polygraph Institute isn’t a business. It merely supervises government agencies’ use of polygraph technology, and hasn’t “accepted” voice analysis (in Endler’s word) as legitimate. It could well be a turf war. It could also be that the technology is the gimmick that the Defense Department says it is: Aside from Sommers’ study — peer-reviewed and published in an academic journal in 2006 — the research is scant. Endler also criticized the Defense Department for relying on laboratory experiments rather than actual cases of interrogation. But the Sommers study published in 2006 included “field questioning.” The results were not statistically different from scripted questioning.

Still, local agencies have no qualms about using the technology, which is inadmissible in court (whether it’s traditional lie detectors or voice-stress analysis). Volusia’s and Flagler’s sheriffs call it an added tool in law enforcement. In Flagler, the sheriff says that merely mentioning that a voice-stress analysis will be part of a job interview prevents some people from applying. But is that necessarily a good thing? Is a job interview — or a police interrogation — not inherently stressful?

Technology that makes or breaks the fate of suspects in police custody has unquestionable merit — so long as the merits are proven beyond reasonable doubt. Short of that, the technology is no more than a tool of deception itself.

Well said.