The lie detector is actually a polygraph, and is usually referred to as a lie detector test in the United Kingdom, in America the home of the lie detector its known as the polygraph. A polygraph examination is also referred to as a psychophysiological detection of deception (PDD) examination. The lie detector is a scientific machine / procedure that measures and records several physiological indicators, these are sweat grand activity, blood flow, blood pressure, breathing and movement while an examinee is asked a series of questions over multiple lie detector charts depending on the format of the exam, results are taken from an average over the charts. Depending on the format of the lie detector test the results will be Deception Indicated for a fail or No Deception Indicated for a pass. A screening lie detector test would have the results of No Significant Reaction for a pass or Significant Reaction for a fail. In all lie detector tests there is a chance the result could be inconclusive, fortunately using the latest techniques there is only a four percent chance of achieving this result.
Lie Detector Results
The lie detector will show deceptive answers as they produce physiological responses that can be differentiated from those associated with non-deceptive answers during the test. There are, however, no specific physiological reactions associated with lying, making it difficult to identify factors that separate liars from truth tellers. Polygraph examiners should all use validated scoring techniques and a recent push in the industry has been to use computerised scoring as this can be more accurate. Lie Detectors UK use ESS scoring and whilst we always manually score the charts we also use the ESS Algorithm built into the Stoelting software, this acts as a double check and only increases accuracy, any issues at this stage we would refer for a full quality control with another examiner.
The Empirical Scoring System (ESS) is an evidence-based numerical scoring model for manual test data analysis (TDA) of psychophysiological detection of deception (PDD) test data from examinations conducted using comparison question test (CQT) formats founded on decades of research. The ESS is designed to provide the field examiner with a validated and reliable scoring model based on the simplest available solutions for which there is published evidence of validity to support all principles, assumptions and procedures. The simplicity of the ESS means that scoring skills are readily acquired by inexperienced scorers, easily retained by both experienced and inexperienced scorers, and easily understood when explained to non-polygraph professionals.