The science of polygraph testing is based on far more than the technology of the polygraph instrument. The interview skills of the examiner are paramount in ensuring an effective testing process free of ambiguity or doubt.
Firstly the Examiner must obtain a comprehensive brief which identifies the circumstances, issues, allegations and facts in dispute.
Secondly, the examiner reviews the material, and formulates test questions in such a way as to elicit clear and complete responses. It is critical not to ask questions which can result in partial answers. In this stage the material gathered from the Pre-test brief is broken down into its component parts and matched to the appropriate questions.
Thirdly, the examiner takes the participant into the testing phase. This is where the sensors are attached to the examinee and the recording process commenced. The questions are read to the examinee several times during the recording process. Typically a minimum of three charts are recorded. After each question is asked a 25 second period follows whereby the instrumentation records autonomic responses to each. Finally the data collected from the polygraph charts is printed and the results numerically scored. The test results are then given to the relevant parties. Final results are possible. Truthful, Deceptive, In order to reduce distractions for the examinee polygraph exams are conducted in private with no other persons permitted in the examination room (other than an interpreter if required).