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NCJ Number: 202091 Find in a Library
Title: Scoring Cutoffs -- Picking the Best
Journal: Polygraph  Volume:32  Issue:2  Dated:2003  Pages:86-96
Author(s): James R. Wygant
Date Published: 2003
Page Count: 11
Type: Report (Study/Research)
Format: Article
Language: English
Country: United States of America
Annotation: This study applied various polygraph "cutoff" rules (minimum scoring levels that permit conclusions) to 200 polygraph examination scores, based on the results of 2 examiners independently scoring the same 100 verified examinations.
Abstract: Error rate, rate of definite results, false positive results, and false negative results were compared for 13 different "cutoff" decision rules, including several rules developed specifically for this study. All of the rules were applied to the same 200 examination scores to determine whether any 1 rule achieved significantly better results for the 2 examiners than any of the other rules. The rule used by most examiners is the +/-6, under which any total score of +6 or higher indicates truthfulness, and any total score of -6 or lower indicates deception. Other "cutoff" rules used in the study were +/-5, +/-4, full DoDPI (uses +/-6 as minimum total scores but adds some important exceptions), +/-6 or any -3, Senter A, Senter B, +/-6 or any -4, +/-4 or any -3, -6/+4, -6/+4 or any -3, -7/+5, and -5/+6 or any -4. The findings suggest that asymmetric cutting scores, such as -7/+5, may achieve better results than the more traditional +/-6. Under asymmetric cutting scores, a specified total minus score or lower would indicate deception, but a specified plus score or higher would indicate truthfulness. The author advises, however, that among any group of examiners, no matter how large, individual differences in scoring are likely to cause "cutoff" rules to shift up and down any scale of errors and definite results. 6 tables, 1 figure, 3 references, and a 12-item bibliography
Main Term(s): Science and Technology
Index Term(s): Investigative techniques; Polygraph reliability; Polygraph techniques; Polygraph training; Polygraphs
To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=202091

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