Halifax councillor wants municipal polygraph testing policy

A Halifax councillor wants the city to develop a policy on polygraph testing for municipal employees.

Shawn Cleary said polygraph testing is done mainly on people who work for Halifax Regional Police.

The District 9 councillor said the tests do not seem to be providing the safeguards they were meant to provide.

"Maybe the polygraph tests aren't working the way they intended, given the fact that we've had many police officers charged with theft, stealing from the evidence locker, assault," he said.

Cleary said there are several variables that can affect the outcome of a polygraph test, including the operator, the machine used, the disposition of the candidate and the type of questions asked.

"So developing a policy that is public, is transparent, is open to scrutiny, especially by decision makers in the city, I think is the only way we we go from here," he said.

His views on the reliability of polygraph tests are shared by Nicole Adams-Quackenbush, an expert in deception detection who did her masters at Saint Mary's University. She's now a lecturer at Newcastle University in Newcastle upon Tyne, England. She said humans are only 60 per cent accurate in detecting deception. 

Describing the polygraph as "not very reliable," Adams-Quackenbush said one of the main problems is that the data given by polygraphs is interpreted by humans. 

"There are studies out there that show that different polygraph examiners come up with different results," she said. 

She said a polygraph does not actually detect lies but rather it measures a number of physiological changes in the subject, including heart rate, blood pressure and skin conductance.

The subject of a polygraph test is first asked a series of straightforward questions that have a known correct answer and this establishes a baseline. Adams-Quackenbush said it is then up to the polygraph examiner to determine if deviations from the baseline are significant enough to determine if the subject is lying.

Adams-Quackenbush said she has friends who joined the Halifax Regional Police and were afraid of having to do the polygraph test. She was told by them that the police try and scare the candidate into telling the truth during the test.

"I would say that if you're trying to hire people with integrity, you shouldn't have to scare them into telling the truth and that we should be looking for other ways to measure that integrity," she said.

Adams-Quackenbush said although polygraphs are used widely in the United States, England and Japan, there's a good reason the Supreme Court of Canada ruled them inadmissible in court.

She warned that although people may think the tests are benign and a normal part of hiring practices, there's a darker side.

"They've ruined lives ... so we need to be careful with these things because like I said, it's usually the truth tellers that are willing to bare their soul and the deceivers that should be," said Adams-Quackenbush.

Police statement

In an email to CBC News, police spokesperson Const. John MacLeod confirmed that polygraphs are one of the tools used for screening employees.

"In relation to polygraph usage for investigations, I cannot speak to specific incidents but what I can tell you is that investigators use a variety of tools at their disposal, including polygraph testing, to advance investigations," he wrote.

The polygraph was invented by Nova Scotian John Augustus Larson in 1921.

Cleary will ask for a staff report on the matter at council on June 29.

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