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Tuvia Shurany
Polygraph chart evaluation, scoring methodologies, and field validity studies of comparison question techniques
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About Tuvia Shurany
Tuvia Shurany is the former head of the Department of Polygraph at the Israeli Government School and President of Lie Catcher Polygraph Services, based in Costa Rica. He served as former Director of the International Polygraph Training Center, which was an American Polygraph Association accredited school, and is the Assistant Director of the Academy for Scientific Investigative Training for Central and South America. As an internationally known lecturer and polygraph instructor, he has conducted polygraph courses throughout Central and South America as well as Europe.
Shurany has made significant contributions to polygraph literature and methodology. He authored "Evaluation of Polygraph Charts: Formats, Criteria and Scoring", a text recommended as a valuable handbook by Cleve Backster and Dr. James Allan Matte. His research has focused extensively on chart evaluation techniques, scoring methodologies, and field validity studies. Notable contributions include his work on the Polygraph Validation Test (PVT), which was successfully employed in re-examinations to rectify original problems and/or confirm attempts by examinees at countermeasures or augmentations. His 2016 paper demonstrated that the Anticlimax Dampening Concept exists in polygraph examinations, and his field validity studies have examined techniques including the Integrated Zone Comparison Technique and Quadri-Track Zone Comparison Technique.
Within the professional polygraph community, Shurany is Vice President of the International Society of Polygraph Examiners, as well as a full member of the Israeli Polygraph Association and the American Polygraph Association. He is listed as a Full Member of the British and European Polygraph Association representing Israel. His most frequent collaborator has been Nathan J. Gordon, with whom he co-authored "The Pre-test Interview- The Foundation of Polygraph", published in both English and Spanish editions. He has published numerous articles on polygraph techniques and theories, primarily in the European Polygraph journal, addressing practical field applications including testing special populations and resolving conflicted results.
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Researchers who have co-authored studies with Tuvia Shurany.
Publications [10]
All peer-reviewed studies by Tuvia Shurany in our database.
Directed Lie – The Correct or the Easy Way?
The study found that 28.6% of directed lie questions failed to provoke physiological reactions during stimulation tests, and three examinees refused to lie as directed, challenging fundamental assumptions about the… [002] 2018 European PolygraphIdiosyncrasies in Chart Evaluation
The study found that individual physiological response patterns vary significantly, with EDA contributing 55% of reactions, cardio 26%, and pneumo 19%. The authors argue that statistically rare response criteria should… [003] 2016 European PolygraphAnticlimax Dampening Concept: It Does Exist
The examinee displayed strong reactions only to the knife threat question (R8) despite being deceptive about both the knife incident and ongoing possession of stolen property, demonstrating that psychological set… [004] 2015 European PolygraphUsing the Polygraph Validation Test (PVT) in Solving Conflicted Polygraph Results and Confirming Deliberate Distortions by Examinees
The PVT successfully resolved all 51 cases of conflicted polygraph results and confirmed suspected deliberate distortions, with classic physiological patterns (POT reactions) indicating when examinees improperly focused attention on comparison… [005] 2013 European PolygraphTesting a Deaf Mute Examinee in Costa Rica
The paper documents practical approaches for adapting polygraph examination procedures to accommodate examinees with hearing and speech disabilities. [006] 2011 European PolygraphPolygraph Verification Test
The PVT provides examiners with a validated tool for confirming suspicions about test interference when original polygraph results are questionable or conflicted. [007] 2010 European PolygraphConfirmed Mental Countermeasure Case in Costa Rica
Mental countermeasures were successfully identified and confirmed through examination procedures, demonstrating the detectability of covert attempts to defeat polygraph testing. [008] 2010 European PolygraphThe Integrated Zone Comparison Technique and ASIT PolySuite Algorithm: A Field Validity Study
IZCT with ASIT PolySuite achieved 98.73% accuracy excluding inconclusives (92.9% including them), while manual 3-point scoring achieved 98.71% accuracy excluding inconclusives (91.7% including them), demonstrating exceptional field validity and near-perfect… [009] 2009 European PolygraphA Field Study on the Validity of the Quadri-Track Zone Comparison Technique
The study provided real-world validation data for the Quadri-Track ZCT technique, representing the third published field research validation of this methodology originally developed in 1977. [010] 2009 European PolygraphInfluence of case facts on blind scorers of polygraph tests
The study assessed whether contextual information, particularly incriminating evidence like fingerprint matches, biases blind scoring of polygraph quality control reviews.Explore all research.
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