This is one of the 4 models of computer polygraph systems that are in use to date. The computer polygraph system utilizes computer scoring (1) objective scoring analysis, (2) magnitude analysis and (3) probability analysis. (4) In addition most, examiners utilize national standardized scoring in addition to the computer algorithms.
What the Computer Polygraph Systems Records
Two channels of respiration (Thoracic and Abdominal) from UFI Pneumotrace transducers.
Skin conductance from silver-silver chloride electrodes (either reusable or disposable attachments).
Cardiovascular activity from a blood pressure cuff.
(optional) Finger pulses from a sensitive photoelectric plethysmograph.
(optional) Skin potential from silver-silver chloride electrodes (either reusable or disposable attachments).
(optional) Voice events from examiner and subject.
(optional) Subject movement from an activity sensor placed on the seat of the subject's chair or under the feet of the subject's chair.
(optional) Auxiliary channel that can be configured to record one of several measures, including skin potential, continuous blood pressure, EKG, or others.
The analog system of polygraph utilizes electronically enhanced system of modules that record Breathing, blood pressure pulse rate and galvanic skin Response for detection of physiological changes that are related to lie detection.
This instrument is still in current use by many examiners. The system is as accurate as the Computer System. Do not allow anyone to sell you the bill of goods that the only accurate system for lie detection is the Computer system. Both Systems of polygraph testing are 95% to 98% accurate in the hands of a polygraph expert. My company utilizes both systems for the polygraph procedures.
Accuracy is also highly dependent on the skill of the polygraph examiner who conducts the test, the suitability of the subject, and appropriate issues for the test.
As a side note:
As in all professions, there are the individuals that are in business to make, take or pry valuable monies from your hands. The service of polygraph is an old scientific method that has come a long way. With the advent of the Computer and the Scoring Polygraph System that was scientifically developed by the John Hopkins University, Utah, Polygraph has progressed from the so called lie box to the lie detector system now respected by the community and used in the federal courts. Professional Polygraph Examiners should have no problem giving you their credentials to verify. (who they are and how long they have been in business) Ask your examiner questions in reference to his background and experience. Do not be shy or you could be the next victim of the unscrupulous examiner that does not take his professions serious. There are persons that have studied the polygraph procedure out of a book. Look out. Ask for references.