Literature Review on Polygraph Accuracy. While the physiological targets of polygraph testing have not changed much since the 1930s, numerous testing techniques, question formats, scoring systems, and specialized applications have emerged since then. The plethora of approaches and the associated lack of standardization have made it difficult to provide clear estimates of polygraph accuracy. In the late 2000s the American Polygraph Association undertook an exercise to validate testing techniques (American Polygraph Association, 2011). All of this has provided a better scientific basis on which to evaluate the efficacy of polygraph testing.
In “Literature Review of Polygraph Accuracy” we take a look at some of the studies and analysis on the accuracy of polygraph examinations
To this end Norman Ansley found in 1983 – When research is conducted using real polygraph cases in which independent means are employed to check truth or deception, the average validity is 96 percent, with a range of 86.3 to 100 percent (Twelve criminal studies, involving 1,964 polygraph examinations were considered) These statistical results do not include those examinations in which the results were reported as inconclusive. When research is conducted in a laboratory setting when truth and deception is known (except to the examiner) the validity of polygraph techniques averaged 93.6 percent, with a range of 69 to 100 percent. (Twenty-Eight laboratory studies, involving 1,113 polygraph examinations were considered). But not all of these laboratory studies cited were conducted to determine validity, some were projects to evaluate variations in techniques, methods of analysis, specific and often single physiological recordings, and specific types of subject population. For example, the third study by Heckel was of delusional psychotics which showed low validity, 69 percent, while the studies of psychopaths resulted in a surprise, with an average detection rate in excess of 90 percent.
In 1990 Norman Ansley followed up with a report on validity from all studies of real cases, conducted since 1980. Examiners decisions in these studies were compared to other results such as confessions, evidence, and judicial disposition. The ten studies reviewed considered the outcome of 2,042 cases, and the results, assuming that every disagreement was a polygraph error, indicated validity of 98 percent, and for non-deceptive cases 97 percent. These studies were from police and private cases using a variety of polygraph techniques, conducted in the United States, Canada, Israel, Japan and Poland. That polygraph techniques are cross cultured is evident from the similarities of the results of studies made in Poland, Israel, Iceland, Japan, Canada and the United States.
A third party review of polygraph accuracy has been carried out by the National Academies of Science in the United States. It concluded that:
“polygraph tests can discriminate lying from truth telling at rates well above chance, though well below perfection” (National Research Council, 2003, p. 4). Accuracy for the most commonly used test format, the comparison question test was estimated to be between 81 to 91 percent, which is highly supportive of a meaningful association between what the polygraph records, truth telling and deception. The National Academies review was carried out on behalf of the US Department of Energy.
Also see the Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques, a report prepared for the American Polygraph Association Board of
Directors – Nate Gordon, President (2010-2011).
We use the technique and scoring algorithms that have shown the highest scores for accuracy, those being the Matte Quadri Track Zone Comparison Technique and the Objective Scoring System 2.0. The MQTZC has validation studies that place it’s accuracy at 99.4% with a 3% inconclusive rate. The OSS2.0 has validation studies that place it’s accuracy at 94%-95% with a 10% inconclusive rate.
We began by taking the natural logarithm of the asymmetrical ratios, standardize them for each component using the mean and standard deviation values obtained through a bootstrap of 10,000 resampled sets of size equivalent to the training dataset of confirmed ZCT cases (N=292) from the sample for OSS version 2.
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