Admissibility of polygraph tests: The application of scientific standards post- Daubert .

The U.S. Supreme Court’s decision in Daubert modernized the long-standing Frye precedent and requires courts to make scientific judgments. Courts, however, are not well-equipped to parse scientific arguments and the Daubert criteria offer only a rudimentary framework for decision-making. To illustrate the problems, as well as possible ways for courts to deal with scientific evidence, the paper focuses on the controversy over admissibility of polygraph (so-called “lie detector”) test evidence. Application of the Daubert criteria for assessing whether polygraph test results can stand as admissible evidence are considered. The concepts of “reliability” and “validity”, as used in the behavioral sciences, are discussed in relation to polygraph testing and the key question suggested by Daubert as to whether extant research actually tests the accuracy of polygraphy is examined. This discussion demonstrates the difficulties in attempting to apply the Daubert criteria, because validity is a very broad concept with both theoretical and empirical aspects, and because proper empirical tests of any scientifically-based technique must satisfy complex methodological criteria. The present analysis demonstrates that although the validity of polygraph test results has been examined across many studies, none of them satisfies the necessary criteria, and therefore, accuracy rates of polygraph test results are unavailable. If Daubert criteria are to be applied, social scientists and courts need to develop a common language. Although it is unreasonable to expect judges to develop the skills of expert scientists, they must become educated science consumers. There is some evidence, at least in the case of polygraph testing, that courts are making these complex judgments and that justice is being served.