Module 5 - Polygraph Testing & Forensic Document Analysis

Polygraph Examiner Training

Polygraph instruments are operated by individuals known as polygraph examiners or polygraphists.   Police departments select police officers with a minimum of five years experience to be trained as polygraphists.   Those chosen also must have records of excellent  investigative skills.

Months of extensive training are required to become a polygraph examiner. A well-trained polygraph examiner can detect lying with a high degree of accuracy.  During polygraph training, an individual learns how to&

• ask the right type of questions
• conduct a polygraph examination
• interpret the various physiological data
• identify visual indicators exhibited by a person who is lying

In Canada, all polygraphists must take a three-month training course at the Canadian Police College in Ottawa, Ontario, to be certified.

Who gets polygraphed?

A polygraph examination is an effective tool in criminal investigations.  The polygraph exam can help to reduce the number of possible suspects.  Polygraph examinations can be used to interrogate a suspect, whcih often leads to a confession of guilt. They can also help confirm whether potential witnesses are reliable. 

Polygraph examinations are also used for employment screening.  Any serious applicant wanting to work for a major police department is given a polygraph exam.  A person would be disqualified from working for a police department if he or she gives deceptive answers to questions about illegal drug use, employment dishonesty, or involvement in any serious crimes. Polygraph exams are often given to potential employees wanting to work for certain government agencies and some drug manufacturing companies. 

In February 2001, Robert Hanssen, a 25-year veteran with the Federal Bureau of Investigation (FBI), was arrested and accused of spying. For over 15 years, he had passed secret information about the United States to the former Soviet Union and Russia. When Hanssen was hired by the FBI, he was not given a polygraph examination. Hanssen's arrest lead  the FBI to change this practice and give all potential employees polygraph exams and to select randomly and give polygraph exams to current FBI employees. The FBI gives over 5000 polygraphs a year to potential employees wanting to work for the US government; each applicant takes two separate tests.

The Use of Polygraph Test Results in Court

Canada, 1987: A witness came forward with information regarding Alain Béland and Bruce Phillips. Shortly thereafter Béland and Phillips were charged with conspiracy to commit robbery.  Béland and Phillips complained that the witness was lying and tried to get the court to allow them both to take a polygraph exam to prove their innocence.  The trial judge rejected the request and they were found guilty.

Later in 1987, the Supreme Court of Canada in a five to two decision supported this verdict.  They stated that polygraph evidence was inadmissible in court because it unnecessarily complicates the process and brings in too many uncertainties due to the possibility of an error. The Béland and Phillips case and the supreme court decision supporting the verdict became a precedent for future cases. Despite this verdict, polygraph testing is seen by law enforcement as an effective tool that can be used in combination with other investigative techniques to solve crime. 

As technology improves, so does the reliability and validity of polygraphing. The range of accuracy from various scientific studies into the reliability of polygraph examinations is between 70% and 90%.  A major study in 2002 by the National Academy of Sciences (NAS) stated that polygraph data is "& reliable, but lacks validity .  Polygraph exams achieve accurate and consistent results, but they are not 100% correct in determining whether the individual is being truthful or deceptive.

Did you know?

"I can talk to people from all different walks of life.  I don't put myself above anyone and I can talk to anyone.  Three things that need to be done during a polygraph interview: get information, give information, and make a friend.  That's how you get people to talk.  If you can do that, your job is done."

- James Calams (Former police officer and professional polygraphist)

Continue to read a case study involving polygraph use...