According to this morning's Washington Post, "The CIA, the FBI and other federal agencies are using polygraph machines more than ever to screen applicants and hunt for lawbreakers, even as scientists have become more certain that the equipment is ineffective in accurately detecting when people are lying."
The intelligence community has long depended on the polygraph as a part of its process for vetting potential employees. The CIA is now using it to find out who leaks information to the press. Yet as Larry C. Johnson writes, quoting friends in the intelligence community, "it only works against folks who have a conscience and a strongly developed sense of right and wrong." In truth, it measures anxiety, not lies.
The Post article cites a study made in 2002: "...if polygraphs were administered to a group of 10,000 people that included 10 spies, nearly 1,600 innocent people would fail the test -- and two of the spies would pass." And there's the rub.
The polygraph can provide an agency with information--valuable information--that it might not get otherwise. People fear the polygraph and will come clean about things that they would hide otherwise. That is the rationale for using it. Another rationale, not mentioned by the Post is that an agency appears to increase security when it uses it; an agency that abandoned it would be perceived as becoming less concerned with security.
But the flip side of this test is the large number of false positives that it gives. Is it better to catch 2 out of 10 spies or to implicate 1600 people? According to the article, the FBI fails a quarter of the people it tests. The CIA fails 30-40 percent of the entry-level applicants it tests. That last number is worse than it seems: these applicants have already gone through most of the pre-employment processing; the agency has determined that it wants them.
The costs of using the polygraph are high, in morale, talented people lost because they failed, and the effort to conduct them. These costs have not been measured against the benefits. Let us hope that the current brouhaha leads agencies to rethink how they use this tool.
