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NCJ Number: 193244 Find in a Library
Title: Assessment of the Total Chart Minutes Concept with Field Data
Journal: Polygraph  Volume:30  Issue:4  Dated:2001  Pages:228-243
Author(s): Donald J. Krapohl
Date Published: 2001
Page Count: 16
Type: Report (Study/Research)
Format: Article
Language: English
Country: United States of America
Annotation: This article examines data from six separate studies to determine evidence of conformity with dependability curves for the Total Chart Minutes Concept.
Abstract: The Total Chart Minutes Concept (TCMC) is a specialized habituation model for polygraph testing. Each of the three traditional channels of polygraph data are more diagnostic at certain periods during polygraph testing than in others, and no two channels have the same exact periods of good and poor productivity. Dependability curves were created to represent the diagnosticity of each of the channels as a function of time. Six sets of data were examined. The data consisted of 7-positon numerical scorings of confirmed field Comparison Question Technique polygraph cases. Scores were summed within channel and chart, then averaged by group, deceptive or nondeceptive. The resulting values were then plotted. The lack of agreement between the various independent field data scoring profiles and the TCMC dependability curves is evidence that the TCMC has little foundation in reality. The TCMC should be viewed with skepticism until supporting data are found. One finding dealt with the question of which polygraph channel really is most diagnostic. Greater separation between average nondeceptive scores and deceptive scores for a channel might signal that that channel was contributing more diagnostic information toward correct conclusions. Another finding dealt with the differences in the pattern of responding between deceptive and nondeceptive examinees. Mounting evidence shows that scoring systems should have cutting scores that are not symmetrical around zero, since the psychophysiological phenomenon is asymmetrical. This data shows that there is a need to adjust scoring methods or decision rules to adapt to the asymmetrical patterns of responding between deceptive and nondeceptive examinees. The data also provide evidence that the electrodermal channel provides more diagnostic information than does either of the other two polygraph channels. 22 figures, 11 references, bibliography
Main Term(s): Polygraph reliability; Polygraph techniques
Index Term(s): Analysis; Effectiveness; Evaluation techniques; Police equipment; Polygraphs; Testing and measurement
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