WASHINGTON — The Pentagon's intelligence arm is adding more polygraph studios and relying on outside contractors for the first time to conduct lie detection tests in an attempt to screen its 5,700 prospective and current employees every year.
The stepped-up effort by the Defense Intelligence Agency is part of a growing emphasis on counterintelligence, detecting and thwarting would-be spies and keeping sensitive information away from America's enemies.
A polygraph is not foolproof as a screening tool. The test gives a high rate of false positives on innocent people and guilty subjects can be trained to beat the system, according to expert Charles Honts, a psychology professor at Boise State University.
The National Research Council noted these deficiencies in a 2003 report. The council, an arm of the National Academy of Sciences, found that lie detectors can be useful for ferreting out the truth in specific incidents, but are unreliable for screening prospective national security employees for trustworthiness.
"Its accuracy in distinguishing actual or potential security violators from innocent test takers is insufficient to justify reliance on its use in employee security screening in federal agencies," the council concluded. "Polygraph testing as currently used has extremely serious limitations in such screening applications, if the intent is both to identify security risks and protect valued employees."
John Sullivan, a polygrapher with the CIA for 31 years, noted that turncoat Aldrich Ames, a CIA mole for the Soviets, beat a polygraph test twice.
But the prospect of facing a polygraph can deter future security violations, according to the council's report. That prospect also increases the frequency of admission of violations — taking home classified documents, for example — and discourages people who may be security risks from applying.
The Defense Intelligence Agency would not say how many prospective, current and past employees are screened annually, but a 2002 report to Congress said the agency conducted 1,345 counterintelligence polygraphs.