Polygraphing Players Is Not Cricket

Steve Waugh
Polygraph advocate Steve Waugh

Guardian reporter David Hopps reports in a story published by the Sydney Morning Herald that former Australia cricket team captain Steve Waugh is advocating the use of lie detectors in an attempt to root out corruption in the scandal-plagued sport. Excerpt:

ANDREW Strauss and Mahendra Singh Dhoni will be encouraged to help stamp out corruption in cricket by taking lie-detector tests as the MCC uses the occasion of the 2000th Test match to step up its campaign to clean up the game.

The controversial proposal is the brainchild of former Australia captain Steve Waugh, who wants leading captains such as Strauss and Dhoni to act as ambassadors and role models by voluntarily putting their reputations on the line.

But the proposal is not supported by the Australian Cricketers’ Association, because lie-detector tests are not admissible in court.

”I applaud Steve Waugh for looking at creative and proactive ways to deal with corruption, but we wouldn’t support the use of polygraphs at this point in time,” ACA chief executive Paul Marsh said. ”Results can be affected if you’re nervous or under stress or whatever, so there may be reasons, other than not telling the truth, that you fail it and we couldn’t open players up to that.”

Waugh is at Lord’s as chairman of an MCC world cricket committee working party that was charged last year with investigating ways corruption might be eradicated. He made his chief proposal only metres away from where Strauss and Dhoni supervised practice ahead of a Test series that will decide whether England or India finish the summer as the No 1 team in the world.

The Australia Cricketers’ Association is right to reject lie detector “testing,” as it has no scientific basis. While polygraphy is inherently biased against truth-tellers, the “test” can trivially be defeated using simple countermeasures that anyone can learn and polygraph operators cannot detect.

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The Truth About the Polygraph (According to the NSA)

The National Security Agency (NSA) has produced a video about its polygraph screening program. Watch it here, along with AntiPolygraph.org’s commentary:

The original source video is available here. For commentary on the NSA’s accompanying polygraph leaflet, see our earlier blog post, NSA Leaflet: Your Polygraph Examination.

For a thorough debunking of polygraphy, with extensive citations (including the U.S. Government’s own polygraph literature) that you may check for yourself, see AntiPolygraph.org’s free book, The Lie Behind the Lie Detector (1 mb PDF).

See also these public statements by individuals who have gone through the NSA polygraph process:

And for discussion of polygraph matters, see the AntiPolygraph.org message board.

Kaiser Fung on Lie Detectors

AntiPolygraph.org has received a complementary copy of statistician Kaiser Fung’s new book, Numbers Rule Your World: The Hidden Influence of Probability and Statistics on Everything You Do (New York: McGraw Hill, 2010), a short primer on statistics written for a general audience.

In Chapter 4, Fung addresses the trade-off between false positives and false negatives in diagnostic testing, using as examples drug testing of athletes, polygraph testing of criminal suspects, job applicants, and employees, and data mining for terrorists. Fung explains how altering decision thresholds to lower the rate of false positives necessarily increases the rate of false negatives, and vice versa, and how a low base rate of the thing being tested for in the population being tested can make attempts to detect it impractical.

With regard to polygraphy, Fung in particular focuses on the Preliminary Credibility Assessment Screening System (PCASS), the hand-held lie detector developed by the U.S. Department of Defense to screen locally hired workers and suspected insurgents in Iraq and Afghanistan. Fung shows that even if we were to assume a 90% accuracy rate for the procedure (an assumption not warranted by scientific evidence), given the low incidence of insurgents seeking employment with the US armed forces, many false positives can be expected for every true positive. (Of course, there is also the problem of countermeasures: any insurgents among the hiring pool can readily fool the PCASS.)

Fung closes his treatment of PCASS with a take-home quote from Dr. Stephen Fienberg, who chaired the National Academy of Sciences panel that in 2002 authored a landmark report on polygraphy: “It may be harmless if television fails to discriminate between science and science fiction, but it is dangerous when government does not know the difference.”

Fung also tells the story of Jeffrey Deskovic, from whom interrogators extracted a false confession to the murder of a high school classmate after he failed a polygraph test. After 16 years in prison, Deskovic was vindicated by DNA evidence and released. Fung concludes, “Statistical analysis confirms that many more Deskovics, perhaps hundreds or thousands a year, are out there, most likely hapless.”

A complete review of Numbers Rule Your World is beyond the scope of this blog, but for further commentary, see reviews by Wayne Hurlbert, Andrew Gelman, and Christian Robert.

Dueling Polygraphs in Pittsburgh Beating Case

Jordan Miles
Jordan Miles after police beating

Three Pittsburgh police officers who stand accused of wantonly beating 18-year-old honor student Jordan Miles have all passed lie detector tests. But Miles also passed a lie detector test regarding the incident. So whose lie detector is lying?

Jill King Greenwood reports for the Pittsburgh Tribune-Review:

Three Pittsburgh police officers accused of beating a Homewood teenager during a January arrest near his home passed polygraph tests over the weekend, the president of the police union said.

Officers David Sisak, Richard Ewing and Michael Saldutte took the tests from a private polygraph administrator at the same time that nearly 100 other city officers marched in the St. Patrick’s Day Parade Downtown on Saturday wearing T-shirts in support of the three, who are on paid administrative leave while the city and FBI investigate the Jan. 12 incident.

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An Example of How the Myth of the Lie Detector Is Perpetuated

An article published today in a small town newspaper provides a good example of the sort of shoddy reporting that perpetuates the myth of the lie detector. Lisa Rogers reports for the Gadsden, Alabama Times:

Polygraphs useful law enforcement tool
By Lisa Rogers
Times Staff Writer
Published: Saturday, March 6, 2010 at 9:37 p.m.

A suspect in a sex crime confessed after failing a lie detector test and even confessed to trying to beat the test by doing research on the Internet.

There are several Web sites that claim to have information that teaches someone how to beat a test, said Fred Lasseter, a licensed polygraph examiner and investigator with the Etowah County Sheriff’s Office.

“They tell you things to do to try to beat the system,” Lasseter said, “but beating it takes years of practice. It is very difficult to try to manipulate the system.”

Polygraph operator Fred Lasseter is lying. It doesn’t take “years of practice” to learn how to beat a lie detector test, nor is it difficult. In peer-reviewed research (cited in the bibliography of The Lie Behind the Lie Detector), about half of test subjects were able to fool the polygraph with no more than 30 minutes of training. The fact that a stupid criminal failed to pass a lie detector test and confessed should not be misconstrued as evidence that 1) the polygraph is difficult to beat or 2) that the polygraph is accurate as a lie detector. It is neither. Continue reading An Example of How the Myth of the Lie Detector Is Perpetuated

How Tom Henry Beat the Polygraph

In an oral history posted on YouTube, musician Tom Henry recounts the story of how, as a young Navy seaman, he was caught with a pound of marijuana in his locker, but escaped punishment after fooling the lie detector:

The technique Tom thought of for fooling the lie detector (dissociation) wasn’t very sophisticated. But it evidently worked against what, given the time (1966) was very likely a Relevent/Irrelevant polygraph “test.” For more on various polygraph techniques and how they can be manipulated, see The Lie Behind the Lie Detector (1 mb PDF).

Tom Henry’s story helps highlight the foolhardiness of relying on polygraph results. For more background on how Mr. Henry came to have a pound of marijuana in his locker, see his preceding video, Busted for Pot.

Penn & Teller Bullshit! Lie Detector Episode

As has been discussed on the message board, Penn Jillette, the “bigger, louder half” of the magic and comedy duo Penn & Teller, has disclosed via Twitter that a forthcoming episode of the Emmy Award-winning Showtime series Penn & Teller Bullshit! will concern “the bullshit of lie detectors.” AntiPolygraph.org anticipates that this PTBS episode will be one of the most informative and entertaining ever.

Update: For a synopsis of this episode, see the message board thread, Penn & Teller Bullshit! Lie Detector Episode (Season 7, Episode 5). The full episode itself may be viewed below: