October 8, 2002
U.S. Advised Against Polygraphs
Filed at 3:17 p.m. ET
WASHINGTON (AP) -- Federal agencies should not rely on lie detectors to screen workers and job applicants because the machines simply are too inaccurate, the National Research Council said Tuesday.
``The belief in its accuracy goes beyond what the evidence suggests,'' Stephen Fienberg of Carnegie Mellon University said at a news conference.
Fienberg, chairman of a research panel that studied the use of polygraphs, said depending on the machines could create a false sense of security.
``Overconfidence may lead, in turn, to the neglect of other methods of ensuring safety, such as periodic security reviews,'' Fienberg said.
Kathryn Laskey of George Mason University said agencies that depend on the machinery face tough decisions in applying the results of the tests.
``It's a difficult choice between misidentifying truthful individuals as security risks and allowing national security dangers to go free,'' Laskey said. ``These are tough choices.''
``We stress, though, that no spy has ever been caught (by) using the polygraph,'' she added.
In its report, the council concluded: ``Almost a century of research in scientific psychology and physiology provides little basis for the expectation that a polygraph test could have extremely high accuracy.''
The research council, an arm of the National Academy of Sciences, prepared the study at the request of the Energy Department. Under the law, workers in sensitive positions in department labs are subject to polygraph screening.
The department said it would carefully review the report on what it called a ``very complex subject.''
``The polygraph is one of many tools we use to protect some of the nation's most sensitive secrets. It is not used on a stand-alone basis but as part of a larger fabric of investigative and analytical reviews,'' said Linton Brooks, acting administrator of the department's National Nuclear Security Administration.
The FBI started administering more lie detector tests on its agents as a result of the spy case involving Robert Hanssen, a counterintelligence agent who spied for the Soviet Union and Russia for 15 years. The agency also has been administering polygraph tests at Fort Detrick, Md., and Dugway Proving Ground in Utah, bases with stores of anthrax, seeking information about last year's anthrax mailings. Nuclear plant workers also are getting the tests in greater numbers since the attacks of Sept. 11, 2001.
Frank Horvath, professor of criminal justice at Michigan State University, said, ``If what they're saying is that polygraph testing is not a useful tool in screening because it makes errors, I wouldn't necessarily agree with them.
``I would have to ask what tool they have in mind to replace polygraph screening,'' Horvath said. ``If we wanted to catch a spy or an applicant bent on spying, what would we do? What technique would we use to do that? There is no alternative right now to polygraph testing, and that's why it is used in spite of its shortcomings.''
The Research Council recommended more research into methods of lie detection.
Polygraphs measure heartbeat, blood pressure and other factors that are known to change when people are under stress, as they are when they lie.
People can learn to control those responses to ``beat'' a lie detector, the report said.
Most uses involve examining individuals about a specific crime, and in those cases the machines can tell the difference between lies and truth ``at rates well above chance, though well below perfection,'' the panel concluded.
When using a lie detector to screen workers, an examiner must ask more generic questions or propose hypothetical situations. Because the examiner does not know what plans a spy may be harboring or what minor infraction a good worker may have done in the past, stress will be recorded during the test.
Thus, screening is likely to produce large numbers of false positives without catching all potential security risks, the report said.
In screening a population of 10,000 workers that included 10 potential spies, if the exam is set at a level designed to catch 80 percent of the spies, an estimated 1,606 nonspies also would fail the test, while eight of 10 spies would be caught, the report said.
On the other hand, if the test had been set to reduce false positives, only two spies would have been detected, and 39 honest workers still would have failed.
The committee noted a widespread belief among the public that lie detectors are accurate, which it said may discourage some potential security risks from applying for jobs for which they know they will face such a test.
On the Net: National Academy of Sciences: http://www.nationalacademies.org