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Scientists Give the Lie to Polygraph Testing

Security: The tool has failed to ferret out spies and other threats, an expert panel concludes.


Polygraph testing for national security screening is little more than junk science, with results so inaccurate that they tend to be counterproductive, according to a long-awaited report released Tuesday by the National Academy of Sciences.

The nation's premier scientific organization said such tests, a key counterespionage tool for 50 years, promote false confidence that spies and other national security threats have been ferreted out.

Produced by experts in psychology, engineering, law and other fields, the report confirms long-standing doubts about the validity of polygraph testing that led to a 1988 federal law banning the use of such tests for employment screening in most private businesses.

Polygraph results are also inadmissible as evidence in nearly all state courts, with federal courts leaving the decision up to the judges.

"If logic has anything to do with it, then the report will have a major policy impact," said Steven Aftergood, an intelligence analyst with the Federation of American Scientists.

"I don't think federal agencies stop and ask themselves how many spies have we caught with this--because the answer is 'none'--or how many people have been unfairly denied employment, because the answer is 'many.' "

Federal security agencies would not discuss the report's conclusions Tuesday, saying they needed time to review the 333-page report in detail.

The U.S. government subjects thousands of job applicants or employees in sensitive positions to "lie detector" tests each year.

The CIA and the National Security Agency administer polygraph tests to all job applicants and employees. The FBI and the Defense Department also test extensively, particularly since last year's terrorist attacks. Such screenings are also common at large police departments nationwide.

"The polygraph has been, and continues to be, one of a number of useful tools in the applicant screening process," said CIA spokesman Paul Nowack.

Linton Brooks, acting head of the National Nuclear Security Administration--the agency responsible for the United States' nuclear weapons stockpile--said the agency will reassess its use of polygraphs in light of the new report.

"It is used not on a stand-alone basis but as part of a larger fabric of investigative and analytical reviews to help security personnel determine who should have access to classified information," Brooks said.

A Pentagon spokesperson said the Defense Department has valued the polygraph "as an investigative tool" for half a century, but agrees that further research would be valuable.

Some experts say the wide-ranging and authoritative report, which was prepared by the academy's research council based on 19 months of study, could trigger changes in security practice for agencies that depend on polygraph testing.

"It is going to be a watershed" that shifts the burden of proof from polygraph skeptics to its advocates, said Paul Giannelli, a law professor at Case Western Reserve University and a consultant to the national academy panel.

"The report is so devastating that it will affect all uses of the polygraph," he said, noting that the panel concluded that the government has "wasted millions of dollars and ought to go in a different direction."

However, advocates of polygraph screening were unsurprised by the study's conclusions. They disagree that profound changes in security strategy are warranted during a war on terrorism that often comes down to fuzzy questions of intent.

"Although it is clearly not a perfect screening tool ... nothing has come along that people have felt good enough about to replace the polygraph," said Michael O'Neil, former general counsel of the CIA.

"That's why it is not an exclusive tool" but one of several methods to determine security clearances, he said.

Other national security veterans concurred.

"It's one of the few tools you have that coerces more candor than the person offers up voluntarily, that a civilized society finds acceptable," said Stewart Baker, a former general counsel of the National Security Agency.

He added that the report should be considered carefully, but that the real-world experience of intelligence agencies may trump an academic analysis.

The study was underwritten by the Department of Energy, which was embarrassed by contradictory interpretations of polygraph tests on accused nuclear spy Wen Ho Lee in 1998 and 1999.

The Taiwanese-born scientist pleaded guilty to one felony charge, but he was ultimately exonerated of spying, and the furor over his case indirectly prompted the polygraph study.

The 2002 national defense authorization bill now requires the Department of Energy to revise its current polygraph policy--under which about 2,000 employees are tested annually--based on a review of this new study.

Many people often assume that polygraph machines literally detect lies. Actually, they measure changes in physiological signals--blood pressure, heart and breathing rates, and perspiration--thought to characterize deception.

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