plied, with possible expert systems for combining polygraph results with other data.

Courts following the Daubert rule on admissibility of scientific evidence are likely to look increasingly to scientific validation studies in judging the uses of polygraph data in court. The existing validation studies have serious limitations. Laboratory test findings on polygraph validity are not a good guide to accuracy in field settings. They are likely to overestimate accuracy in field practice, but by an unknown amount. The available field studies are also likely to overestimate the accuracy achieved in actual practice. Assessments of the polygraph for the purposes of forensic science should take into account the test’s design, function, and purpose because both the accuracy of the test and the practical meaning of particular accuracy levels are likely to depend on these factors.