Bierman & Associates welcomes the opportunity to present in this brief
document a few essential facts about polygraph testing. We hope you will find
the information to be of interest and will be pleased to supply you with additional
materials and information you may need.
What is a Polygraph?
The term “polygraph” literally means “many writings”. The name refers to the manner in which selected physiological activities are simultaneously recorded. Polygraph examiners may use conventional instruments, sometimes referred to as analog instruments, or computerized polygraph instruments.
It is important to understand what a polygraph examination entails. A polygraph instrument will collect physiological data from at least three systems in the human body.
A typical polygraph examination will include a period referred to as a pre-test, a chart collection phase and a test data analysis phase. In the pre-test, the polygraph examiner will complete required paperwork and talk with the examinee about the test. During this period the examiner will discuss the questions to be asked and familiarize the examinee with the testing procedure. During the chart collection phase the examiner will administer and collect a number of polygraph charts. Following this, the examiner will analyze the charts and render an opinion as to the truthfulness of the person taking the test. That opinion will be truthful, deceptive, or in a small percentage (ten to twelve percent) inconclusive, where no opinion will be rendered. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. It is important to note that a polygraph does not include the analysis of physiology associated with the voice. Instruments that claim to record voice stress are not polygraphs and have not been shown to have scientific support.
How Accurate is the Polygraph?
Hundreds of research studies of specific incident testing converge to an accuracy of over 90%. More importantly, the National Academy of Science, after reviewing numerous research studies have answered the question as to whether or not the polygraph can reliably tell truth tellers from deceivers. The answer is, Yes!
Who uses Polygraph Examinations?
The three segments of society that use the polygraph include law enforcement agencies, the legal community, and the private sector. They are further described as follows:
Law Enforcement Agencies – Federal Law Enforcements Agencies, State Law Enforcement Agencies and Local Law Enforcement Agencies such as Police, the Sheriff’s Department
Legal Community – U.S. Attorneys Offices, District Attorney Offices, Public Defenders Offices, Defense Attorneys, Civil Litigators, Parole and Probation Departments
Private Sector – Companies and Corporations under the restrictions and limitations of the Employee Polygraph Protection Act of 1988 (EPPA)
Private citizens in matters not involving the legal or criminal justice system
Attorneys in civil litigation – He said/she said situations
How can I tell if the Polygraph Examiner
Professional associations such as the American Polygraph Association (APA), Florida Polygraph Association (FPA), etc. have strict educational and experience requirements. Membership and certification of expertise in these organizations is a good place to start.
Like picking a surgeon, look for someone with experience, reputation and credentials. Referrals from the legal/law enforcement community can be of assistance as well.
Are there Errors in Polygraph Examinations?
Yes! Though they are rare. False positive, False negative – White the polygraph technique is highly accurate, it is not infallible and errors do occur. Polygraph errors may be caused by the examiner’s failure to prepare the examinee for the examination, or by a misreading of the physiological date on the polygraph charts. Errors are usually referred to as either false positives or false negatives. A false positive occurs when a truthful examinee is reported as being deceptive, a false negative when a deceptive examinee is reported as truthful. Some research indicates that false negatives occur more frequently than false positives; other research studies show the opposite conclusion. Since it is recognized that any error is damaging, examiners utilize a variety of procedures to identify the presence of factors, which may cause false responses, and to insure an unbiased review of the polygraph records.
Will nervousness affect the test?
No, it is normal to be nervous undergoing a polygraph examination. Everyone is. Your examiner knows this and his education, experience and instrumentation enables him to mitigate its effect.