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The Polygraph and Lie Detection
ees who are being considered for new assignments, typically at a higher level of clearance.
They are used for screening current employees, especially in security-sensitive occupations. For example, the U.S. Department of Energy polygraph program, established in 1999, mandated polygraph examinations for about 1,300 employees in sensitive positions; a year later, the program was expanded to cover several thousand additional employees (P.L. 106-65 and P.L. 106-398).
They are used in investigations of specific events, for instance, in criminal cases. Although there are many restrictions on the use of polygraph results in courts, they are often used to help direct and focus criminal investigations.
These three uses of the polygraph raise very different scientific and practical questions, as discussed in this report.
The polygraph continues to be the subject of a great deal of scientific and public controversy in the United States. A 1983 report by the U.S. Office of Technology Assessment examining the validity of the polygraph raised many criticisms that are still being voiced. The 1988 Employee Polygraph Protection Act sharply limited the use of polygraphs in employment settings, largely because of doubts about its validity for screening. Different courts have different sets of rules about the admissibility of polygraph evidence and even about what test must be met for such evidence to be considered admissible. Many people find polygraph testing objectionable, and there are several websites and organizations devoted to discrediting the polygraph.
It is against this background of continuing controversy that the committee was given the charge to “conduct a scientific review of the research on polygraph examinations that pertain to their validity and reliability, in particular for personnel security screening.” We were also asked to “review other techniques that may be adapted for similar purposes . . . in order to allow for a comparative evaluation of the polygraph and to suggest directions for future research that may include both polygraph and other tests.” Based on our review, we were asked to present our “assessments of and recommendations for polygraph examinations for personnel security purposes” and to suggest further research.1
THE INSTRUMENT, THE TEST, AND THE EXAMINATION
Polygraph testing combines interrogation with physiological measurements obtained using the polygraph, or polygraph instrument, a piece of equipment that records physiological phenomena—typically, respiration, heart rate, blood pressure, and electrodermal response (electrical