pailryder wrote on May 25^th, 2008 at 7:52pm:


My own experiences were sufficient to convince me that the polygraph is not accurate.  I told the truth on four polygraph exams and only passed once.

Between the examiner and the examinee, there is only one person in each test who knows whether the polygraph results are accurate.  The examiner can make an educated guess based on their training and experience, the examinee knows for certain.

pailryder wrote on May 25^th, 2008 at 7:52pm:



Ok, what is the latest research, so we can get back on track!!!

Quote:


http://www.nap.edu/openbook.php?record_id=10420&page=213

Here is an excerpt:"Overestimation For the reasons cited, we believe that estimates of polygraph accuracy from existing research overestimate accuracy in actual practice, even for specific-incident investigations. The evidence is insufficient to allow a quantitative estimate of the size of the overestimate.

Estimate of Accuracy Notwithstanding the limitations of the quality of the empirical research and the limited ability to generalize to real-world settings, we conclude that in populations of examinees such as those represented in the polygraph research literature, untrained in countermeasures, specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance, though well below perfection.

Accuracy may be highly variable across situations. The evidence does not allow any precise quantitative estimate of polygraph accuracy or provide confidence that accuracy is stable across personality types, sociodemographic groups, psychological and medical conditions, examiner and examinee expectancies, or ways of administering the test and selecting questions. In particular, the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures. There is essentially no evidence on the incremental validity of polygraph testing, that is, its ability to add predictive value to that which can be achieved by other methods."

Note:  My underlining above.  The above is talking about use of polygraph when an actual crime has been committed or a specific incident has occurred and is being tested for.  Rates of accuracy for employment screening is way less.   

Read also  http://antipolygraph.org/articles/article-051.pdf

which discusses:

1)  Probability that a person who PASSES the test is actually telling the truth (NPV).

2)  Probability that a person who FAILS the test is actually being DECEPTIVE (PPV).

Above report studied preemployment screening tests only, I believe.




TC

Hunter wrote on May 28^th, 2008 at 4:20am:


Selected research is still research.  There were no claims made that the NAS research study used every scrap of availabe research ever done on the polygraph.

The reference material used in the NAS research study are listed here: http://www.nap.edu/openbook.php?record_id=10420&page=232.

polytechnic wrote on May 28^th, 2008 at 3:36pm:


I think it is appropriate to review the case facts so we can know what we are talking about.  Nothing sillier than an examiner trying to talk intelligently about something they know nothing of.  And, no.  I do not think it unduly prejudices an examiner.  I have tested many people where the facts were against them and they passed, and visa-versa.

I have certainly had tests where I questioned the results.  Any examiner should be able to admit it.  Remember, we're dealing with human beings, therefore, as I have stated previously, things can be "screwy" for a lot of reasons (Please don't ask me to list them, I'm tired).  If I find a mistake in my testing procedure or (or sometimes) the examinee's actions, I almost always offer a re-examination.  I stay focused on trying to obtain the truth, not a specific result.

As for false positives.  I have probably had some (statistics would be so polite to me).  However, I can not recall an examination where I called the examinee deceptive and later, evidence exonerated them. 

As for hypertension, etc, I do not automatically see apnea as CM's.  If it is the normal state of the individual, then it should be taken into consideration.  What is there to "address" if it is normal?

Sackett

Hunter wrote on May 29^th, 2008 at 1:49pm:


As discussed previously on this forum by myself and Dr. Richardson, the "study" to which you refer ("The Validity and Reliability of Polygraph Testing") is a non-peer-reviewed meta-study of mostly non-peer-reviewed studies that was prepared for an interested party (the American Polygraph Association) by a past president of that association (Norm Ansley). It does not merit serious consideration by anyone seeking a science-based assessment of polygraph accuracy.

Hunter,

There simply is no body of peer-reviewed research proving that polygraphic lie tests reliably work at better-than-chance levels under field conditions. I'm not claiming that polygraphy has been proven not to work, but rather that -- in the 90 or so years since William Moulton Marston unveiled the lie detector -- it has not been proven to work.