HOW IT WORKS
THE LIE DETECTOR (POLYGRAPH) EXAMINATION PHASES
A polygraph examination consists of three distinct phases:
I. Pre-Test Phase (Information Collection, Relevant Questions/Statements Formulation);
II. In-Test Phase - Polygraph Examination (Chart Collection);
III. Post-Test Phase (Data Analysis, Scoring Procedure).
I. PRE-TEST PHASE (Information Collection, Relevant Questions/Statements Formulation)
During this first phase the examiner will:
obtain the examinee’s/client's version of the facts regarding the specific issue under investigation;
formulate and review with the examinee/client all the questions that will be asked during the polygraph examination.
provide the examinee with a detailed explanation of the polygraph procedure, as well as the polygraph instrument and its components.
II. IN-TEST PHASE / POLYGRAPH EXAMINATION (Chart Collection)
The polygraph examination takes place during this second phase. Just before beginning the examination, the blood pressure cuff will be inflated to a pressure of 60 mmHg. The examiner will then ask the examinee the series of questions that were formulated and reviewed during the pre-test interview. This series of questions will be asked a minimum of three times. As the examinee answers the questions, his or her physiological data are continuously collected, measured, and recorded by the polygraph instrument.
The examinee will have a relaxation period of approximately two minutes between each series of questions..
III. POST-TEST PHASE (Data Analysis, Scoring Procedure, Results).
During this last phase, the examiner will analyse and evaluate the physiological data by means of scientifically-based numerical quantification system, and will render one of the following results:
No Deception Indicated: The examinee is telling the truth.
Deception Indicated: The examinee is not telling the truth.
Inconclusive: The evaluation of the examinee’s physiological data is inconclusive.
(less than 5% of all conducted tests).
THE POLYGRAPH INSTRUMENT
The computerised polygraph instrument collects, measures, and records physiological data obtained from three major systems in the human body, all of which are controlled by the Autonomic Nervous System.
Cardiovascular System: Heart rate, relative blood pressure, blood volume;
Respiratory System: Respiratory activity;
Electrodermal System: Galvanic skin response, i.e., sweat gland activity.
Following the pre-test interview, the polygraph examiner will place various painless components on and around the examinee’s body, thereby connecting him or her to the polygraph instrument. These components are equipped with sensors that serve to collect the examinee’s physiological data as he or she answers the series of previously reviewed questions during the course of the polygraph examination.
1) A standard blood pressure cuff applied to the examinee’s upper left arm for the purpose of recording cardiovascular activity;
2) Two convoluted rubber tubes (called pneumographs), placed over the examinee’s chest and abdomen to record respiratory activity;
3) Two small metal plates (called galvanometers), attached to the fingers of the examinee’s right hand to record Galvanic skin response, i.e., sweat gland activity;
Before beginning the polygraph examination, the examiner will administer a stimulation/calibration test. The purpose of this test is threefold:
To find and fix examinee's physiological baseline at the time of the test through which the expected nervousness or anxiety of the examinee will not affect the test.
To obtain adequate tracings of the examinee’s physiology to ensure that he or she is a suitable candidate to undergo a polygraph examination.
POLYGRAPH EXAMINATION REPORT
Upon completion of the polygraph examination, the examiner will provide the client with a verbal result. A written verified report, detailing the information received during the polygraph procedure and the examination result, will be sent to the client (at no extra cost) within 24 hours after the test completion.
SYSTEMS AND METHODOLOGY
All polygraph examinations are administered in accordance with the Code of Ethics and the set of Standards and Principles of Practice required by the American Polygraph Association (APA) - the world's leading association dedicated to the use of evidence-based scientific methods for credibility assessment.