The United States Supreme Court, in April of 1998, reaffirmed its' position that polygraph results should not be admissible in court because,
The contentions of respondent and the dissent not withstanding, there is simply no consensus that polygraph evidence is reliable. To this day, the scientific community remains extremely polarized about the reliability of polygraph techniques. Further the accuracy of the polygraph is little better than could be obtained by the toss of a coin, that is, 50 percent.
Some studies have concluded that polygraph tests overall are accurate and reliable. See, e.g., S. Abrams, The Complete Polygraph Handbook 190-191 (1968) (reporting the overall accuracy rate from laboratory studies involving the common control question technique polygraph to be in the range of 87 percent). Others have found that polygraph tests assess truthfulness significantly less accurately - that scientific field studies suggest the accuracy rate of the control question technique polygraph is little better than could be obtained by the toss of a coin, that is, 50 percent.
Despite a well written argument in support of the polygraph's accuracy, the Supreme Court recognized the fact that, in practice, polygraph results are unreliable - bottom line. The FBI should take note. Also, James Murphy, Head of the FBI's Polygraph Unit, cautions against the use of the polygraph. Please note that the Supreme Court cited controversial studies by Dr. Lykken and Dr. Iacono in reaching its opinion.
FBI Special Agent Thomas Lewis, in U. S. v. Gilliard, testified that he is not able to name even one case where the FBI concluded that a private polygraph was valid.
SUPREME COURT OF THE UNITED STATES
United States (Petitioner) vs. Edward G Scheffer
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[Polygraph screening] is completely without any theoretical foundation and has absolutely no validity the diagnostic value of this type of testing is no more than that of astrology or tea-leaf reading.
former Supervisory Special Agent
Dr. Drew C. Richardson,
FBI Laboratory Division
Polygraph is more art than science, and unless an admission is obtained, the final determination is frequently what we refer to as a scientific wild-ass guess (SWAG)
retired CIA polygrapher
John F. Sullivan
Whether it is screening applicants or screening employees, the polygraph is a failure. I suspect that its days as a screening tool are deservedly near an end.
former FBI Special Agent Mark Mallah
[The CIA's] reliance on the polygraph is truly insane
former CIA Director John M. Deutch
The AMA has taken a stand against these machines and testified before Congress in support of the 1988 Employee Polygraph Protection Act. Once again, there is no way to explain why a subject--healthy or ill--may have "failed." These "tests" are simply not a reliable way to measure truthfulness.
American Medical Association
The Association believes there is convincing evidence to suggest that the use of the lie detector is arbitrary, subjective, biased toward accusations of guilt and claims of very high validity are scientifically indefensible.
B.C. Civil Liberties Association