Western Polygraph > How Does a Polygraph Examination Work?

How Does a Polygraph Examination Work?

The polygraph examination is divided into three segments: The pretest phase, the data collection phase, and the data analysis phase.

In the pretest phase the examiner will complete the required paperwork and familiarize the individual with the testing procedure and the instrumentation. The examiner will review the entire process, to include the attachments, the process, the matter at hand and most importantly, the examiner will review every question with the individual. An individual walks into a polygraph that in itself is a brand new experience. The last thing anyone wants during an examination is to be surprised.

In the data collection phase the examiner administers the test and collects a number of polygraph charts depicting physiological changes occurring with the examinee’s body as the examiner reads each test question and the individual answers “yes” or “no.” That’s correct. These are simple yes and no answers.

In the data analysis phase, the examiner will carefully review and score each chart in order to render an opinion as to the truthfulness of an individual’s answers. The opinion rendered will be one of the following: No Deception Indicated meaning the individual answered the relevant questions truthfully, Deception Indicated meaning the individual did not tell the truth to the relevant test questions, or sometimes the opinion is Inconclusive/no opinion when the examiner is unable to determine truth or deception from the polygraph charts due to abnormal or inconsistent physiological reactions.

If Deception is indicated, the individual is given the opportunity to explain his deceptive physiological responses as displayed on his polygraph charts.