UPDATE: Benjamin Birkbeck was convicted and sentenced to 40 years in prison. According to prosecutor Kevin McMurray, the polygraph "evidence" (portions of which are demonstrably untrue) "helped a lot." See Reply #4 below.

It appears that Steven D. Duncan, a polygraph examiner with the Georgia State Patrol, past president of the Georgia Polygraph Association, and member of the American Polygraph Association's Board of Directors, did some "testilying" in a Georgia courtroom on Wednesday, 2 May 2007. According to a Newnan, Georgia Times-Herald report by Elizabeth Richardson, in response to a defense argument that the defendant may have truthfully answered a control question regarding falsification of documents, "Duncan rebutted that the test was more likely to call a liar honest than to call an honest person a liar." (emphasis added)

Who in the polygraph community actually believes this to be true? Who among you can cite any peer-reviewed research that would support Duncan's claim?

On the contrary, it is widely recognized -- even by polygraph examiners -- that Control Question Test polygraphy is inherently biased against the truthful and that false positives are more likely than false negatives. Fear of the consequences of not being believed may cause truthful persons to react strongly to the relevant questions, and, perversely, the more honestly one answers the "control" questions, and as a consequence exhibits less anxiety when answering them, the more likely one is to wrongly fail.

If Elizabeth Richardson's reporting is accurate, I can come to no other conclusion but that Steve Duncan lied on the stand.

Here is the relevant portion of the Times Herald article (a PDF printout of the entire article is attached for reference purposes):

Quote:

Polygraph evidence presented in Birkbeck retrial
Published 5/3/07 in The Times-Herald
By ELIZABETH RICHARDSON
erichardson@newnan.com

New evidence involving a polygraph test of the defendant was presented as the retrial of Benjamin Birkbeck, the East Point Police Officer accused of molesting a young woman, continued Wednesday in Coweta Superior Court.

Assistant Coweta Circuit District Attorney Kevin McMurry said Birkbeck voluntarily submitted to the polygraph test on April 12 with consent from both the prosecution and the defense.

The prosecution called Steve Duncan, an investigator and expert polygrapher with the Georgia State Patrol, to testify about the polygraph he administered.

"The results clearly indicated that he was deceptive with his answers to those [relevant] questions," said Duncan. "[The results were] not a close call at all."

Duncan explained the science of polygraphy. As a polygrapher, Duncan tests a subject's cardiovascular system, breathing and sweat production. Tests are not 100 percent accurate because of such variables as the technique of the person administering the test, the equipment and the phrasing of the questions.
"Maybe 2 to 3 percent [of polygraph tests] are ever deemed inconclusive," added Duncan.

The questions asked of Birkbeck were "designed" by both the defense council and prosecution using Duncan's methodology, according to his testimony.

On April 12, Birkbeck had a cold and was on three medications. Duncan advised it should not skew the results but gave Birkbeck the option of postponing. Birkbeck gave consent. Duncan discussed each question's exact wording with the defendant to ensure he understood everything being asked. In the test, the victim was referred to as "that girl" so as to avoid emotion, Duncan said.

Prior to the test, Birkbeck underwent a practice test, during which he lied about something irrelevant to allow the instrumentation to adjust to his physiology.

Despite Birkbeck's cold, Duncan "saw no problems as far as conducting the test" and described it as "textbook."

Birkbeck was asked 10 questions three times that addressed the sexual allegations as well as his overall honesty, according to Duncan.

Birkbeck was asked if he was seated; if he intended to answer truthfully; if he believed Duncan would only ask the agreed-upon questions; if prior to 2006 he had ever lied about work issues; if he had touched the girl in a particular manner; if prior to 2006 he had ever falsified an unofficial report; if he'd touched the girl at his home; if there were other things he was afraid Duncan would ask him about; if prior to 2006 he'd ever lied to someone in authority; and, finally, if he'd touched that girl in a sexual way.

In cross-examination, Birkbeck's attorney, John Frederick Nebl, questioned the validity of the test by further pushing the issue that Birkbeck had a cold at the time. He also said that Duncan's polygraph instrumentation adjusted to Birkbeck's physiology by assuming he'd lied to the control question, when he may not have. Physiological results indicated Birkbeck had truthfully never falsified documents, which was meant to be a control question that most people would lie to.

Duncan rebutted that the test was more likely to call a liar honest than to call an honest person a liar.
Also, according to Nebl, Birkbeck requested to take the test again when advised of the results, and Duncan denied his request.

Asked during redirect by McMurry whether he doubted the results in any way, Duncan said there was "no question in my mind."