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The Polygraph and Lie Detection (2003) / Chapter Skim
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Appendix I: False Positive Index Values for Polygraph Testing
Pages 354-357

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From page 354...
... These ratios vary somewhat with the threshold selected, but they illustrate how much difference it would make if a high value of A could be achieved for field polygraph testing. If the diagnosis of deception could reach a level of A = 0.90, testing would produce much more attractive tradeoffs between false positives and false negatives than it has at lower levels of A
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From page 355...
... The figures are based on the binormal, equivariance model and are presented on logarithmic scales to make it easier to get accurate readings for very low base rates than is possible with standard scales such as presented in Figures 7-1 and 7-2.
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From page 356...
... 1— 80% 50% ~20% ~ \ \ _ ~ it. \ \ 1 1 1 1 1 1 111 1 1 1 1 1 1 111 1 1 1 1 1 1 111 =- 1 1 1 1 1 1 11 0.0005 0.005 0.05 0.50 0.0001 0.001 0.01 0.10 1.00 Base Rate of Poor Security Risks FIGURE I-1 False positive index values as a function of base rate of deception for a diagnostic procedure with an accuracy index (A)
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From page 357...
... ~ (in 1 0 5— 0.5— O . 1 ~ r ~ L ~ T ~ I I ~ [lI 0.0005 0.0001 0.001 80% ~50% ~20% I T ~ I I ~ TlI T 1 1 1 1 1 111 1 1 1 1 1 1 11 0.005 1 0.05 1 0.50 0.01 0.10 1.00 Base Rate of Poor Security Risks FIGURE I-4 False positive index values as a function of base rate of deception for a diagnostic procedure with an accuracy index (A)
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Key Terms

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  • index values
  • base rate
  • accuracy index
  • diagnostic procedure

  • threshold values
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  • achieving sensitivities
  • polygraph test
  • test result

  • polygraph testing
  • major security
  • correctly identified
  • lower levels
  • security risks

  • test accuracy
  • attractive tradeoffs
  • false positives
  • optimistic assessments
  • base rates

  • false negatives
  • truly positive
  • low base
  • accuracy rates
  • accuracy makes

  • increasing test
  • threshold selected
  • field polygraph
  • derive values
  • correctly detect


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