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Posted by George W. Maschke
- Sep 04, 2007, 06:45 AMOn 5 September 2007, in a follow-up to an episode titled "Backstabbing Sisters," the Dr. Phil show featured former DEA polygrapher John Swartz of Houston, Texas, who polygraphed sisters Stacy and Christy regarding allegations of child pornography and physical abuse:
http://www.drphil.com/shows/show/920
A video clip of the polygraph portion of the episode is posted here for discussion purposes (30 mb mp4):
https://antipolygraph.org/video/dr-phil-05-09-2007.mp4
In this episode, Dr. Phil McGraw, who with a Ph.D. in clinical psychology should know better, has once again abused his audience's trust by promoting belief in the pseudoscience of polygraphy. The main piece of disinformation that needs to be laid to rest is found in the following exchange:
Dr. Phil goes on to endorse that claim. But the National Academy of Sciences recently concluded an exhaustive review of the scientific evidence on the polygraph and reached a very different conclusion (at pp. 212-13, emphasis in the original):
Indeed, there is broad consensus amongst scientists that polygraph "testing" has no scientific basis. The only ones claiming 90th percentile accuracy rates for polygraphy are the polygraph operators themselves -- and showmen like Dr. Phil who cynically use the polygraph as a ratings gimmick.
We see from the video that like former FBI polygrapher Jack Trimarco, who also made a recent appearance on the Dr. Phil show, John Swartz is not using a pressure sensitive seat pad in an attempt to detect or deter countermeasures such as the anal sphincter contraction or pressing one's toes to the floor during the asking of the so-called "control" questions:
My next observation is that, as is usually the case on the Dr. Phil show, the polygraph results tended to confirm the conclusion that most viewers would have reached on their own absent the polygraph. The allegations of child pornography and physical abuse had already been investigated by police and Texas Child Public Services, both of which had determined that no action was warranted.
Regarding John Swartz's conduct of the polygraph examinations, the segment suggests that sister Stacy was polygraphed first. Swartz gave her a passing score with regard to each relevant question asked. Thus, by the time he polygraphed sister Christy, he would be expected to have had a strong bias toward finding her deceptive on at least one of the relevant questions.
We don't know what "control" questions were asked of either sister, but here are the relevant questions asked of Stacy:
Note that question #5 is a question that Stacy could not have definitively answered. It would have been better prefaced with, "To your knowledge..."
These are the relevant questions that Christy was asked. She "failed" the last two:
After the dramatic results of Christy's polygraph "test" have been revealed, Dr. Phil quizzes polygrapher John Swartz about the results, just to make sure there was no mistake about it:
Q.E.D., according to Dr. Phil. However, the show provided no information that would independently corroborate Swartz's finding of deception on Christy's part. Also left unaddressed by Dr. Phil is the fact that sister Christy passed what is arguably the most important relevant question she was asked:
5. Did you ever give false information about Stacy to Child Protective Services? No. (NDI)
http://www.drphil.com/shows/show/920
A video clip of the polygraph portion of the episode is posted here for discussion purposes (30 mb mp4):
https://antipolygraph.org/video/dr-phil-05-09-2007.mp4
In this episode, Dr. Phil McGraw, who with a Ph.D. in clinical psychology should know better, has once again abused his audience's trust by promoting belief in the pseudoscience of polygraphy. The main piece of disinformation that needs to be laid to rest is found in the following exchange:
John Swartz avers his polygraph results are 98-99% accurate
QuoteDr. Phil McGraw: What is the degree of accuracy that you think you have attained with this particular test?
John Swartz: Most of the academic studies on specific issue testing since 1980 -- that entails tests just like this -- 98 to 99 percent accuracy across the board.
Dr. Phil goes on to endorse that claim. But the National Academy of Sciences recently concluded an exhaustive review of the scientific evidence on the polygraph and reached a very different conclusion (at pp. 212-13, emphasis in the original):
QuotePolygraph Accuracy Almost a century of research in scientific psychology and physiology provides little basis for the expectation that a polygraph test could have extremely high accuracy. The physiological responses measured by the polygraph are not uniquely related to deception. That is, the responses measured by the polygraph do not all reflect a single underlying process: a variety of psychological and physiological processes, including some that can be consciously controlled, can affect polygraph measures and test results. Moreover, most polygraph testing procedures allow for uncontrolled variation in test administration (e.g., creation of the emotional climate, selecting questions) that can be expected to result in variations in accuracy and that limit the level of accuracy that can be consistently achieved.
Theoretical Basis The theoretical rationale for the polygraph is quite weak, especially in terms of differential fear, arousal, or other emotional states that are triggered in response to relevant or comparison questions. We have not found any serious effort at construct validation of polygraph testing.
Research Progress Research on the polygraph has not progressed over time in the manner of a typical scientific field. It has not accumulated knowledge or strengthened its scientific underpinnings in any significant manner. Polygraph research has proceeded in relative isolation from related fields of basic science and has benefited little from conceptual, theoretical, and technological advances in those fields that are relevant to the psychophysiological detection of deception.
Future Potential The inherent ambiguity of the physiological measures used in the polygraph suggest that further investments in improving polygraph technique and interpretation will bring only modest improvements in accuracy.
Indeed, there is broad consensus amongst scientists that polygraph "testing" has no scientific basis. The only ones claiming 90th percentile accuracy rates for polygraphy are the polygraph operators themselves -- and showmen like Dr. Phil who cynically use the polygraph as a ratings gimmick.
We see from the video that like former FBI polygrapher Jack Trimarco, who also made a recent appearance on the Dr. Phil show, John Swartz is not using a pressure sensitive seat pad in an attempt to detect or deter countermeasures such as the anal sphincter contraction or pressing one's toes to the floor during the asking of the so-called "control" questions:
No seat pad on this chair
No activity sensor tracing on these charts
My next observation is that, as is usually the case on the Dr. Phil show, the polygraph results tended to confirm the conclusion that most viewers would have reached on their own absent the polygraph. The allegations of child pornography and physical abuse had already been investigated by police and Texas Child Public Services, both of which had determined that no action was warranted.
Regarding John Swartz's conduct of the polygraph examinations, the segment suggests that sister Stacy was polygraphed first. Swartz gave her a passing score with regard to each relevant question asked. Thus, by the time he polygraphed sister Christy, he would be expected to have had a strong bias toward finding her deceptive on at least one of the relevant questions.
We don't know what "control" questions were asked of either sister, but here are the relevant questions asked of Stacy:
Stacy on the box
Quote1. Did you ever give false information to Child Protective Services or the police? No. (NDI)
2. Did you ever file a false or knowingly inaccurate birth certificate? No. (NDI)
3. Did you falsify any of the information you presented when you appeared on the Dr. Phil show? No. (NDI)
4. Have you ever physically abused any of your children? No. (NDI)
5. Has your husband ever sexually abused your children? No. (NDI)
6. Does your husband have a known history of pedophilia? No. (NDI)
7. (Repeated) Did you falsify any of the information you presented when you appeared on the Dr. Phil show? No. (NDI)
Note that question #5 is a question that Stacy could not have definitively answered. It would have been better prefaced with, "To your knowledge..."
These are the relevant questions that Christy was asked. She "failed" the last two:
Christy on the box
Quote1. Did Stacy ever call you to advise you that she had found pornography on her husband's computer? Yes. (NDI)
2. Did you have Stacy's permission to remove that computer from her residence? Yes. (NDI)
3. Did you place any images of child pornography on Stacy's husband's computer during the time it was in your possession? No. (NDI)
4. Other than the forensic examiner, did you have anyone else tamper with the computer's hard drive? No. (NDI)
5. Did you ever give false information about Stacy to Child Protective Services? No. (NDI)
6. Did Stacy ever ask you to suppress any information about her husband's activities? Yes. (DI)
7. Did you falsify any of the information you presented when you appeared on the Dr. Phil show? No. (DI)
After the dramatic results of Christy's polygraph "test" have been revealed, Dr. Phil quizzes polygrapher John Swartz about the results, just to make sure there was no mistake about it:
"No question at all," says a confident John Swartz
QuoteDr. Phil: You're confident in these results? Deception was found on two questions: whether she had been asked to suppress information and whether she had provided false information on this show.
John Swartz: Absolutely.
Dr. Phil: And both of those found deception...
John Swartz: Yes.
Dr. Phil: Was that a close call, or was it clear?
John Swartz: No question. No question at all.
Dr. Phil: It was clear.
Q.E.D., according to Dr. Phil. However, the show provided no information that would independently corroborate Swartz's finding of deception on Christy's part. Also left unaddressed by Dr. Phil is the fact that sister Christy passed what is arguably the most important relevant question she was asked:
5. Did you ever give false information about Stacy to Child Protective Services? No. (NDI)