Have you ever wondered what a polygraph test is or thought, “Do these test really work”? If so here is a break down about the Polygraph test and the pros and cons about using this type of test. The foundation built on the Polygraph test is that telling a lie is stressful and because of this stress there can be a measurement made and recorded to see if you are telling the truth. The Polygraph gets its name because the test consists of simultaneously monitoring several of the suspect’s physiological functions. The most important and functions to be tested are breathing, pulse, and galvanic skin response. These functions are recorded and printed on graph paper for the observer to determine.

Arguments For and Against



  • Few people can control all three physiological functions at the same time
  • Polygraph examiners run pre-examination tests on suspects, enabling the examiners to measure that individual’s reaction to telling a lie.


  • Some subjects can conceal stress even when they are aware that they are lying.
  • It is at times unclear to distinguish an individual’s stress generated by the test and the stress generated by a particular lie.

According to the American Polygraph Association there has been over 250 studies conducted on the accuracy of polygraph testing during the past 25 years. In fact the most recent computerized testing research reveals that the accuracy of computerized polygraph systems is close to 100%. Most of the known errors occur with polygraph examiners that are simply not as experienced. In many cases the Polygraph tests have been proven reliable and have a history of helping police and private investigators solve the problem. If you or someone you know are in need of a Polygraph test feel free to contact the PI Agency. Our advice is always free, 1-888-777-0683

Polygraph Testing