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Polygraph and CVSA Forums => Polygraph Procedure => Topic started by: beech trees on Jun 27, 2001, 01:52 AM

Title: CQs in criminal investigations
Post by: beech trees on Jun 27, 2001, 01:52 AM
Are the typical control questions discussed in 'The Lie Behind The Lie Detector' as described for screening polygraphs the same one would find in a criminal investigation polygraph, or a polygraph test concerning specific incidents known to have occured?
Title: Re: CQs in criminal investigations
Post by: George W. Maschke on Jun 27, 2001, 05:12 AM
Probable-lie "control" questions are similar in both screening and specific incident polygraph examinations. However, in the latter case, they are generally worded in such a manner as to exclude from their scope the incident under investigation. "Time bars" are frequently used to accomplish this.

On p. 116 of A Tremor in the Blood: Uses and Abuses of the Lie Detector, (2nd ed.), David T. Lykken provides an example of a CQT administered by David Raskin to a defendant accused of stabbing a man to death. You'll note that the probable-lie "control" questions here all include time bars:



1. Were  you born in Hong Kong?                  Yes  (Irrelevant)

2. Regarding the stabbing of Ken Chiu, do you    Yes  (Sacrifice relevant)
   intend to answer truthfully every question
   about that?

3. Do you understand that I will ask only        Yes  (Outside issue)
   questions we have discussed?

4. During the first 18 years of your life,       No   (Lie control)
   did you ever hurt someone?

5. Did you cut anyone with a knife on Dumfries   No   (Relevant)
   Street on January 23, 1976?

6. Before 1974 did you ever try to seriously     No   (Lie control)
   hurt someone?

7. Did you stab Ken Chiu on January 23, 1976?    No   (Relevant)

8. Is your first name William?                   Yes  (Irrelevant)

9. Before age 19, did you ever lie to get        No   (Lie control)
   out of trouble?

10. Did you actually see Ken Chiu get stabbed?   No   (Relevant)