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POLYGRAPHS

A BRIEF EXPLANATION OF QUESTION CONSTRUCT and SCORING (DI – NDI Calls)

An examination comprises a set of charts. Either 2,3 or 4 charts, dependant on the type of Question Construct being utilised. When testing an Issue (a single act, or felony) the recommended Construct to be used is the IZCT, which has a reliability factor of 99,4%. There are other popular, but less reliable Costructs. It is logical however that an examiner should use the most reliable construct, and not one that he favours (for whatever reason) nor one that was recommended by any other person. All historical and contemporary polygraph research proves to us that the IZCT is the construct of choice for single issue tests. The AFMGQT should NOT be used for Issue tests…..only for Multiple Issue Screening tests, such as Pre-Employment Screening and Periodic Honesty Screening. The AFMGQT screening test, or any other MGQT construct must report separately on each Relevant Question, because each question is a separate issue. Bear in mind that this construct is at best , 82% reliable. NB: There should be no more than Four Relevant Questions in a MGQT construct. Contemporary, peer reviewed polygraph research proves that the ESS (Empirical Scoring System) is the most reliable system. Unfortunately most polygraphists are unable to use this system and take shortcuts by using the onboard PC scoring system. This is another unfortunate behaviour. Only a perfect chart without any artefacts (accidental errors) on a CQ or RQ may be scored with onboard scoring. It is highly unusual to find such charts and this is the prime reason why 99% of examiners decline to produce their charts when a dispute or query arises.


QUEST ONLY USE IZCT PROTOCOL FOR SINGLE ISSUE TESTS 



AFMGQT (Air Force Mixed General Question Tec) Protocol for Screening Tests (Pre-Employment) (Periodic)

This is from the American Polygraph Association

There are several Question Constructs that have scientific validation. Some are archaic and some are particularly useful for Law Enforcement only. As we here are all Commercial Examiners serving a common consumer (Fidelity SS) we must standardise what we do in all aspects of what we practise.

In South Africa the two most common protocols used for investigation examinations are the IZCT and the USAF MGQT. The IZCT is a modern iteration of Backsters Trizone ZOC. The USAF MGQT was introduced into SA primarily by a certain US instructor.

Both of these Protocols are validated by research. However, the USAFMGQT is less reliable or accurate by a clear margin of 12%. Research published on the APA website and reproduced here, illustrates that the USAF has accuracy of 87% for the 10 question version and 82% for the
7 question version.

The IZCT protocol has accuracy of 99%. In view of this wide margin of accuracy, there should be no rationale for using anything else but the IZCT for investigation examinations. Remember always that the IZCT ZOC is a Single Issue Tri-Zone examination.