PolyScore 3.3 and Psychophysiological Detection of Deception Examiner Rates of Accuracy When Scoring Examinations from Actual Criminal Investigations
Final rept. Mar 96-Sep 98
DEPARTMENT OF DEFENSE POLYGRAPH INST FORT MCCLELLAN AL
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A stratified random sample of 200 confirmed examinations were scored using PolyScore 3.3. Three experienced psychophysiological detection of deception PDD examiners scored the 100 Zone Comparison Test ZCT examinations, and three PDD examiners scored the 100 Modified General Question Test MGQT examinations, using a 7 position scale. The scores were converted to 3 position scale for comparison. PolyScore had an overall level of accuracy of 90.9 when scoring the ZCT examinations, but was less accurate when scoring the MGQT examinations. The PDD examiners had an overall level of accuracy of 82.3 and 73.3 using the 7 and the 3 position scoring scales, respectively when evaluating MGQT examinations, but were less accurate on ZCT examinations. A test for the significance of proportion differences was performed on the accuracy data and the differences between numerous comparisons were statistically significant. All computed Kappa values assessing the interrater agreement for the two groups of examiners were statistically significant. Finally, the proportion of concurrence between individual examiners, ranged from 76.8 to 81.0 for the ZCT examinations, and 78.8 to 92.0 for the MGQT examinations when using the 7 position scoring scale. Concurrence was lower when using the 3 position scoring scale.
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