A Study of the Validity of Polygraph Examinations in Criminal Investigation: Final Report to the National Institute of Justice Grant No. 85-IJ-CX-0040.

This project was designed to answer several major questions concerning the validity of the control question polygraph technique (CQP) for assessing truth and deception in criminal investigations. Confirmed and unconfirmed polygraph charts from examinations by the U. S. Secret Service in criminal investigations were sampled and blindly interpreted by six polygraph examiners from that agency and one psychophysiologist at the University of Utah. They were also subjected to computer interpretation using algorithms developed at the University of Utah. The accuracy of human and computer interpretations was very high. Original examiners' decisions on individual relevant questions ranged from 91-96% correct on confirmed truthful and 85-95% correct on confirmed deceptive answers. Blind interpretation produced somewhat lower accuracies, from 63-85% on truthful and 84-94% on deceptive answers. The accuracy of computer interpretations was higher than blind interpretations, ranging from 95-96% on confirmed truthful and 83-96% on confirmed deceptive subjects. The results provide considerable support for the accuracy of decisions by the original examiners and for the use of computer interpretations for quality control decisions concerning the outcomes of polygraph tests. The generalizability of laboratory research on CQP tests was analyzed using computer generated response profiles and double cross-validation of models developed from laboratory and criminal suspects. Results indicated that laboratory findings may provide considerable information about the underlying processes and accuracy of field polygraph examinations. They also indicated a need to improve the choice of relevant questions in multiple issue testing and for modifications to improve the accuracy of field numerical evaluation. [ABSTRACT FROM AUTHOR]

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