Over two hundred and fifty tests have been conducted by or under the auspices of the American Polygraph Association in the past seventy five years on the accuracy of polygraph testing. Since a polygraph examination is a very complex process, and many different conditions and factors are involved in this research, it is difficult to draw from the data a precise figure for the accuracy of polygraph testing in all settings.
However, various independent studies have concluded an accuracy rate of at least 98%, if conducted by a competent examiner, for specific issue investigations. Pre-employment testing is considered to be more or less just as accurate.
While the polygraph technique is not infallible, research clearly indicates that when administered by a competent examiner, the polygraph test is one of the most accurate means available to establish truth and deception.
There are basically two ways to beat a polygraph. Either tell the truth, or don’t do the test.