The GKT can be validated statistically assuming each question is independent and has high entropy (close to 50-50 probability of answer A or B) and that there are enough questions available. The most likely source of error though may be unintentional cues. It is best that the examiner not know the answers to the asked questions to avoid this. Just how difficult this is, even for honest, well intentioned examiners is well understood. Even the most educated and experienced professionals such as medical doctors are careful not to reach broad conclusions without prophylactic measures such as double blind technique.

Here is an example of a widely used practice, "Facilitated Communication" which has proven to be largely bogus yet has significant believers in parts of the academic community and demonstrates the risks inherent in any such process where the examiner's biases may be a factor.

http://soeweb.syr.edu/thefci/apafc.htm

I think that GQT would be amenable to scientific study though since experimental techniques to check the statistics are well known.  This may be particularly applicable here since clinical trials sometimes are done where the underlying processes are not well understood.

-Marty

J.B.,

I don't believe the majority of your polling questions can be meaningfully answered based on currently existing evidence.  Your first question is the clear exception.  Those polygraph methods that are generally classified as concealed information tests (to include the Guilty Knowledge Test) are the only ones with a theoretical basis for practice and which therefore hold any potential as representing valid diagnostic instruments.  None of the so-called "Lie Detection" formats have any scientifically justified basis for practice, contain any semblance of scientific control, have any degree of acceptance in the scientific community, or have any basis for routinely meeting established tests for trial court admissibility.  

Because of the aforementioned shortcomings of those polygraph formats/applications currently most widely in use, I believe concealed information testing represents the only hope for meaningful and productive polygraph practice.  Because these tests will require some effort and other expenditure of resources (most worthwhile endeavors do) to collect and preserve investigative information, it will be incumbent upon the polygraph community during periods of necessary field research and later operational practice (if justified) to do much more than offer the usual lip service paid to this type of examination, i.e., "It's nice to be able to use information-based testing when available…” The extent to which this testing is "available" will be directly related to the efforts put forth by investigators and polygraphers alike as they fufill their respective roles in advance of test administration.

Because others have commented upon the potential problem of examiner bias and its potential effect on in-test stimuli presentation, I suppose I will follow suit.  Because concealed information tests are strictly information based, do not require the pre-test “setting” of control questions, etc., and in general do not require any of the exam-specific interaction between examinee and examiner that occurs in a lie detection test, concealed information tests can be constructed and administered so as to avoid the aforementioned problem.  The guilty knowledge test (questions and alternative answers) can be pre-recorded by an individual completely unfamiliar with the matter being investigated.  Although poor stimulus choice, etc still could exist and confound (as with any test), the potential bias reflected in the voice inflection of a case-knowledgeable examiner would be eliminated as well as any spurious affect/effect produced through the typical "lie detection" pre-test encounter.  A separate benefit (other than eliminating examiner bias effects) of the pre-recording of the exam stimulus set (again, unavailable with lie tests) is that it can be used to validate the stimulus set (not just general validation) for any given investigation.  This is accomplished by having some representation of those known to be familiar with the investigation (e.g., investigators) and those known to be unfamiliar with the investigation take the exam.  By doing this one can look for potential sources of false positive and false negative error and modify the stimulus set appropriately before the administration of the actual examination(s) of interest.

Regards,

Drew Richardson

Drew,

I agree that the use of an information based polygraph, such as the GKT, is as available as one  might make it.  One of the hurdles involved in implementing this type of a test, as I have discovered through personal endeavors, is not in its availability but in refocusing the investigator’s thought process of how and when to use polygraph.   

Inasmuch as the GKT is used at the investigation onset, it can quite readily offer investigators many advantageous uses of polygraph as a forensic examination that are not available to them with a CQT.   

Too list a few of the GKT’s strengths, for those whom are new to it;

1.  It offers investigators a non-evasive test that shields the innocent suspect of an investigation.  A properly conducted GKT is non-accusatory.  A GKT constructed with 16 good 
questions has an assumed false positive error rate of.1% and a false negative error rate of .3%

2.  It provides investigators with a focus early in an investigation, which can most certainly save the investigators and their agency countless investigative hours and resources.
 
3.  It’s is a test that can be mathematically figured to an assumed probability of error rate. (As Drew explained in his last post, a GKT’s assumed probability of error may be   reduced even further by subjecting it to a test against known samples.)   

I know that there are many more advantages in using this type of a test.  I just offered a few to further discussion on this topic.

Marty,

I was just finishing a response to some of your last few messages, when I saw you had posted some new thoughts.  First I will discuss those past assertions.

You brought up the problem of examiner bias.  Bias has the potential for presence in most situations that involve human interaction or decisions, not limited to polygraph.  If an examiner has knowledge of the correct answers to the questions, it does not present a per se bias.  Although a naïve examiner could administer a valid GKT, they could in no way construct one.  Drew’s suggestion of pre-recorded questions and there alternative answers is one way to minimize bias.  Another is to check the original examiner score/rank against blind examiners and algorithms for consistency.  The subjecting of the test to known samples can also presumably reduce bias in a GKT.  If there had been key information leaked, the known sample test would quite probably discover it.

More recently you wrote;

Quote:


You are quite correct in this and I would just add that Japan uses polygraph only for criminal issues in a forensic setting.  Japan refers to their procedure by a different nomenclature, Concealed Information Test (CIT).  Also, polygraph evidence is excepted and used in the Japanese judicial system.   

Marty,

Although guilty construes a person committed a crime and is a verdict in criminal trial, guilty is used in correlation with knowledge for the purposed assertions.  Taken in this correlated context, guilty knowledge definably suggests that a person has or does not have criminal knowledge or knowledge of the crime.  Concealed information suggests that the person has or does not have information of the crime.  When the two are compared, there is little, if any, difference in the prejudice, presumptive, or accusatory inferences of the two avowals.  It is my opinion that the nomenclature was changed to eliminate the presumed need to explore the aforementioned definition in a criminal proceeding , albeit quite simple, and possible preemptive challenges. 

You are correct in saying that the Japanese and Americans convey information to the media on criminal investigations in a different manner.  However, the first amendment does not stipulate the necessity for police to convey specific details about a crime and its investigation to the media.  This has become common practice more frequent and to a greater degrees within recent years for quite different reasons.   

The necessary training to apply the GKT is not so significant.  The prior preparation needed to conduct a good GKT is more significant than that which is found in a CQT.   

Your last statement;

Quote:


I adamantly agree with.

J.B.   

Just an idea to maybe spark some meaningful discussion.  In a past discourse, George asserted the following:

Quote:


Let us return to this discussion but with the GKT  in place of the CQT.  A sort of mirrored discourse, probably more of a discussion.