Report: Polygraphs not made for screening
By Scott R. Burnell
UPI Science News
Science & Technology
Published 10/8/2002 2:38 PM
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WASHINGTON, Oct. 8 (UPI) -- The country's national-security organizations should avoid relying on polygraph examinations to screen out possible spies and other risky individuals, according to a report released Tuesday by the National Research Council.
Overconfidence in lie detectors could be creating a false sense of security among policymakers and others concerned about preventing espionage, said Steven Fienberg, who chaired the NRC committee looking into the issue.
Fienberg, a professor of statistics and computer science at Carnegie Mellon University in Pittsburgh, said the report found insufficient evidence linking deception in screening and changes in body functions such as heart rate.
"(Polygraph) testing yields a choice between two unsatisfactory results," Fienberg told a news conference. "Either too many loyal employees may be falsely judged as deceptive, or too many major security threats could go undetected."
As an example, Feinberg described a hypothetical screening of 10,000 employees, of whom 10 are spies. A polygraph system sensitive enough to detect 80 percent of the spies also would include about 1,600 innocent people for further study, he said. If the test was designed to limit false positives to about 40 people, it would only spot 20 percent of the spies.
"No spy has ever been caught with a polygraph," said study committee member Kathryn Laskey, a professor of systems engineering and operations research at George Mason University in Fairfax, Va. The report stayed away from judging polygraph performance in post-crime investigations.
The scientific basis for using polygraphs in pre- and post-employment screening falls well short of common standards, the report said. In addition, agencies using the tests have yet to create a standard for judging polygraph results and a majority of studies on polygraph use fail to meet quality requirements of groups such as the National Science Foundation.
Committee members with security clearances met with organizations such as the Central Intelligence Agency to see if any classified work pertained to the polygraph study, Fienberg said, but no additional information was uncovered. The committee found nothing that suggested secret studies, if any exist, would avoid the problems found in published research, he said.
"National security is too important to be left to such a blunt instrument," Fienberg said. "The polygraph's (problems) underscore the need to look more broadly for effective, alternative methods."
Unfortunately, current work into techniques such as brain-wave monitoring and body-heat scans has yet to reach the point of an acceptable alternative, he said. Computerizing the analysis of polygraph records shows promise for increasing the test's accuracy, but scientists are waiting for verifiable results in this area, the report said. The report recommends expanded research into methods for detecting and deterring security threats, done preferably by groups with no operational responsibility for such tasks.
The NRC study was sponsored by the Department of Energy, which includes the National Nuclear Security Administration and controls several national labs and other security-conscious sites. Linton Brooks, the NNSA's acting administrator, said the department will consider the study's findings as it develops a new polygraph program.
"The polygraph 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 in a statement. "The NRC study will help policy makers assess the role of the polygraph in our security program."
Copyright © 2002 United Press International
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