Scientific Basis for Polygraph Testing

Abstract

Published scientific literature is reviewed for comparison question polygraph testing and its application to diagnostic and screening contexts. The review summarizes the literature for all aspects of the testing procedure including the pretest interview, test data collection, test data analysis, and a proffer of the physiological and psychological basis for polygraph testing. Polygraph accuracy information is summarized for diagnostic and screening exams. Evidence is reviewed for threats to polygraph accuracy and the contribution of polygraph results to incremental validity or increased decision accuracy by professional consumers of polygraph test results. The polygraph is described as a probabilistic and non-deterministic test, involving both physiological recording and statistical methods. Probabilistic tests, statistical models, and scientific tests in general are needed when neither deterministic observation nor physical measurement are possible. Event-specific diagnostic polygraphs have been shown to provide mean accuracy of .89 with a 95% confidence range from .83 to .95. Multi-issue screening polygraphs have been shown to provide accuracy rates, with a mean of .85 and a 95% confidence range of .77 to .93.