security policy choices, may create an unfounded, false sense that because employees have appeared nondeceptive on a polygraph, security precautions can be relaxed. Such overconfidence can create a false sense of security among policy makers, employees in sensitive positions, and the public that may in turn lead to inappropriate relaxation of other methods of ensuring security. It can waste public resources by devoting to the polygraph funds that would be better expended on developing or implementing alternative security procedures. It can lead to unnecessary loss of competent or highly skilled individuals because of suspicions cast on them as a result of false positive polygraph exams or because they avoid or leave employment in federal security organizations in the face of such prospects. And it can lead to credible claims that agencies that use polygraphs are infringing on individuals’ civil liberties for insufficient benefits to national security.

Broader Approaches The limited usefulness of the polygraph for security screening justifies efforts to look more broadly for ways to improve security. Modifications in the overall security strategies used in federal agencies, such as have been recommended by the Hamre Commission for the U.S. Department of Energy (Commission on Science and Security, 2002), deserve consideration. Ways of improving the accuracy of screening, including alternatives and supplements to the polygraph and innovative ways to combine information sources, also deserve consideration.

Recent Policy Recommendations on Polygraph Screening Two recent reports that advocate continued use of polygraph tests for security screening in federal agencies are partly, but not completely, consistent with the scientific evidence on polygraph accuracy. The Hamre Commission report recommends more restricted use in DOE; the Webster Commission report (Commission for the Review of FBI Security Programs, 2002) recommends expanded polygraph testing in the FBI. Both reports recommend using the polygraph only on individuals who are in positions where they could gravely threaten national security, a stance consistent with the objective of reducing the total costs of false positive errors in testing.

Both reports presumably based their recommendations at least in part on a belief in the utility of the polygraph that goes beyond issues regarding the scientific validity and accuracy.

Neither report explicitly addresses two inherent problems of using a test with the approximate accuracy of the polygraph for screening in populations with very low base rates of spies and terrorists. One is the false positive problem created by the likelihood that the great majority of positive test results will come from innocent examinees. The other, potentially more serious problem, is the false negative problem created by

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