and is not available even for restricted access. Thus it appears that various information sources are combined an in informal way on the basis of the judgment of adjudicators and other personnel. Quality control for this phase of decision making appears to take the form of review by supervisors and of policies allowing employees to contest unfavorable personnel decisions. There are no written standards for how polygraph information should be used in personnel decisions at DOE, or, as far as we were able to determine, at any other agency. We believe that any agency that uses polygraphs as part of a screening process should, in light of the inherent fallibility of the polygraph instrument, use the polygraph results only in conjunction with other information, and only as a trigger for further testing and investigation. Our understanding of the process at DOE is that the result of additional investigations following an initial positive reading from the polygraph test almost always “clears” the examinee, except in those cases where admissions or confessions have been obtained during the course of the examination.

Incremental Validity

Policy decisions about using the polygraph must consider not only its accuracy and the tradeoffs it presents involving true positives and false positives and negatives, but also whether including the polygraph with the sources of information otherwise available improves the accuracy of detection and makes the tradeoffs more attractive. This is the issue of incremental validity discussed in Chapter 2. It makes sense to use the polygraph in security screening if it adds information relevant to detecting security risks that is not otherwise available and with acceptable tradeoffs.

Federal agencies use or could use a variety of information sources in conjunction with polygraph tests for making personnel security decisions: background investigations, ongoing security checks by various investigative techniques, interviews, psychological tests, and so forth (see Chapter 6). We have not located any scientific studies that attempt directly to measure the incremental validity of the polygraph when added to any of these information sources. That is, the existing scientific research does not compare the accuracy of prediction of criminal behavior or any other behavioral criterion of interest from other indicators with accuracy when the polygraph is added to those indicators.

Security officials in several federal agencies have told us that the polygraph is far more useful to them than background checks or other investigative techniques in revealing activities that lead to the disqualification of applicants from employment or employees from access to classified information. It is impossible to determine whether the incremental



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