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Last Updated: Friday, 7 September 2007, 12:32 GMT 13:32 UK
How do telephone lie detectors work?
The Magazine answers...

Man using telephone
'Err... No, I mean yes...'
Britain's largest local authority, Birmingham Council, is to install a telephone lie detection system in an effort to combat benefit cheats. So how will it work?

Software that scans speech patterns is being trialled for weeding out benefit cheats.

In the first three months of a pilot scheme in Harrow, north London, that began in May, 173 housing benefit and council fraudsters were exposed, saving the council 110,000.

This success has led to Birmingham, the UK's largest local authority, being picked as the next council to use the technology, which is known as Voice Risk Analysis (VRA).

VRA is used only in conjunction with questioning by call operators who have been trained to detect deception, says a spokesman for the Capita Group, which owns the technology.

They detect inaudible fluctuations in the human voice, consistent with stress brought about by lying
It works by measuring "micro-changes" to the frequency of the human voice and relaying to the operator, in real time, the level of risk that the speaker is being deceptive.

At the start of the conversation, the software takes the caller's normal voice as the benchmark and accounts for the possibility that changes may be caused by nerves.

"Just because someone gets stressed or uncertain about something does not mean they will be classed as high risk," says the spokesman.


If the caller is deemed by the operator to be low risk, using the test results to support their own judgement, they are fast-tracked and avoid more rigorous vetting.

Those deemed to be at higher risk of lying must supply further evidence to support their claim.

There's no way you can tell from a single telephone call whether someone is lying
Bruce Burgess
Polygraph expert
A spokeswoman for the Department of Work and Pensions, which is partly funding the trials, says: "The vast majority of people who receive benefits are genuinely entitled to them.

"However, there is a minority who are intent on stealing money from those who need it most.

"This technology-based process aims to tackle these fraudsters while speeding up claims and improving customer service for the honest majority."

It is already used in the insurance industry as one of many fraud detection techniques, although representatives for the industry say it is deployed sparingly.

"They are used in exceptional circumstances, not routinely," says a spokesman for the Association of British Insurers. "Only a handful of insurers would use them and only when there are strong grounds to suspect fraud, and as part of a whole package of fraud protection measures."

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But the TUC has voiced concerns about its use on benefit claimants, believing that innocent but nervous people could have their claims delayed or even rejected.

Conventional lie detector systems, called polygraphs, pick up on changes to breathing, sweat glands, heart and pulse.

And Bruce Burgess, a "professionally trained" polygraph examiner, says telephone lie detector systems are about as reliable as tossing a coin.

"There's no way you can tell from a single telephone call whether someone is lying. Before a polygraph test we have to prepare a subject for hours so they trust the examiner and trust the test.

"Otherwise even if they are being truthful, there could be a reaction. The key is to have no surprises."

But telephone tests could work well as a deterrent, he says, because if people think they're being tested, they're less likely to make false claims.

Below is a selection of your comments.

All of the independent research shows that voice-based lie detection systems are completely invalid. No decisions should be based on such a flawed technology.
Dr. Louis Rovner, Los Angeles, California, United States

Given the evidence for polygraph's being inconsistent and easily gamed, I think Bruce Burgess's opinion is pretty worthless. The best way this could work is by Birmingham advertising it far and wide in the hope that it scares off the stealing scum.
Tobin, Brighton

Strange that Bruce Burgess the "Professionally Trained" polygraph examiner doesn't like VRA, guess it might affect his job. Pity that polygraph is also about as accurate as tossing a coin. VRA is only used to highlight further lines of enquiry. It's not going to be used as judge, jury and executioner. More to be used to allow companies/councils to use their budgets more effectively.
SD, Halifax

Birmingham Council should be embarrassed and ashamed to have to have bought into the emperor's-new-clothes technology of voice stress analysis (now being marketed as Voice Risk Analysis). These voice-based lie detectors, like the polygraph, are entirely without scientific basis and are not to be trusted.
George Maschke, co-founder, AntiPolygraph.org, The Hague, The Netherlands

It's amazing how all these 'Big Brother' technologies need a sensationalist news story like this to fool the public into accepting them. CCTV will cut crime! Biochips in passports will stop terrorism! Now phone monitoring will cut benefit fraud! "Any society that would give up a little liberty to gain a little security will deserve neither and lose both."
Lord Farr, London

What if the claim is made using an interpreter?
Edwards, Slough

Waste of time. Lie Detectors, in any form, have been proven time and time again to be seriously flawed in the results they give. But hey if the council wants to waste taxpayers' money chasing something that doesn't really work....
Chris Templeton, Edinburgh

I completely agree with the TUC and their concerns about innocent but nervous people. I get extremely nervous when speaking on the telephone under normal circumstances, even more so when speaking to my bank or other 'official' organisations. I don't claim benefits but if I did I'm sure I would also be nervous when on calls such as those mentioned in the article - I dread to think what kind of results I would produce in one of these so called telephone tests!! It all sounds very unreliable and given that in this country polygraph data is not admissible in a court of law then it should not be used for such purposes as this.
Sarah, London

I think there should be no problem with this. If you have nothing to hide, you have nothing to fear. I for one wouldn't care if this was used by my own local council.
Andie Riley, Leeds, England

Ummm. Lie detectors don't actually work so how do they think this would help them catch cheats? If the cheats force it to the courts they will win! There is no (scientific or otherwise) proof that something as subjective as truth can be detected by a machine! I look forward to this council being sued for the extra stress the will create with their made up test!

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