Accuracy Of Polygraph Tests

The accuracy i e validity of polygraph testing has long been controversial.

Accuracy of polygraph tests. Accuracy and validity of polygraph testing scientific research has shown polygraph examinations to be highly accurate making them very useful in the criminal justice system. According to research noted by the american polygraph association apa website on polygraph validity. According to richard wiseman professor of the public understanding of psychology at the university of hertfordshire testing the accuracy is difficult because you can t simply ask a criminal whether he was lying or not the only method would be to use polygraphs in cases where the true answer had already been established using other evidence. The data show that techniques intended for event specific single issue diagnostic testing produced an aggregated decision accuracy of 89 confidence interval of 83 95 with an estimated inconclusive rate of 11.

According to the american psychological association most psychologists agree that there is little evidence that polygraph tests can accurately detect lies the national research council in its annual report titled the polygraph and lie detection found the high accuracy claims of polygraph exams to be without scientific validity. An honest person may be nervous when answering truthfully and a dishonest person may be non anxious. Polygraph techniques in which multiple issues were encompassed by the relevant questions produced an aggregated decision accuracy of 85 confidence interval 77 93. The american polygraph association apa requires the following to be met before an examination can be considered valid.

There is no evidence that any pattern of physiological reactions is unique to deception. Overview a party seeking to rely on the results of a polygraph test in disciplinary proceedings must adduce expert evidence for the purposes of. Published studies show that several valid polygraph methods have the accuracy of over 90 with a 95 confidence. The credibility of the polygraph was challenged almost as soon as it was invented in 1921 and there is much debate about its accuracy.

Critics of the polygraph system say that the evidence shows these lie detectors are only accurate about 65 of the time hardly better than random chance. The american polygraph association claims that polygraphs are accurate over 90 of the time when properly administered and bias has been removed from the equation. Some experts say the fundamental premise is flawed. An examiner s interpretation is subjective.

But a polygraph is not perfect. Studies have shown that when a well trained examiner uses a polygraph he or she can detect lying with relative accuracy. Also scientific reviews indicate that diagnostic tests have the accuracy of 89 with a confidence range of 83 to 95.