Quebec City police proudly announced in January there had been a drastic decline in hate-related incidents in 2018, the year after six Muslims were murdered at the largest mosque in the city.

"We've been highly aware since the attack," Dominic Gaudreau, a spokesperson for Quebec City police, said at the time.

"That allowed investigators to see what could be done in advance and not to wait for a crime."

But Statistics Canada data shows the number of hate-related incidents in Quebec City is almost three times higher than what was reported by police.

And now the force is refusing to explain what accounts for the difference.

In January, the Quebec City police force (SPVQ) said there had been 27 incidents in 2018, down from 75 the year of the mosque shooting.

Quebec City police responding to the 2017 mosque shooting. The police force declined to provide an explanation for the discrepancy in hate-crime statistics. (Mathieu Belanger/Reuters)

Figures released recently by the federal statistics agency indicate there were 89 incidents in 2018.

"You rarely see that kind of gap," said Barbara Perry, director of the Centre on Hate, Bias and Extremism at Ontario Tech University.

Statistics Canada data on hate crimes is compiled from information provided by police forces.

The numbers are meant to include three types of incidents: offences that meet the Criminal Code definition of a hate crime; crimes where hate was a motivating factor (usually determined at sentencing); and hateful incidents (such as a racist comment).

Quebec City police won't explain difference

Figures on hate-related incidents from the SPVQ and Statistics Canada usually align closely with each other.

In recent years, the only other time there has been a significant difference was in 2014, when the SPVQ reported 31 hate-related incidents while StatsCan had the number at 50.

CBC News asked the SPVQ to explain the discrepancies. The force declined, but a police spokesperson said in an email the numbers were being re-examined.

Capt. Steve Desroches said it was possible that incidents initially flagged as hate-related were later reclassified after further investigation.

But Perry said she would be "stunned" if that were so for more than a handful of cases. Otherwise, she pointed out, it would mean that two-thirds of potential hate incidents were deemed to be unfounded.

"That's quite a stretch," said Perry.

Barbara Perry, a criminologist specializing in hate crime, said that without accurate hate-crime reporting, it is difficult for authorities to address the problem. (CBC)

Another possible explanation put forward by Desroches: Statistics Canada wasn't always updating its number to match the results of SPVQ investigations.

The federal agency declined to comment on the reasons for the discrepancy between its numbers and those of the SPVQ.

But according to Statistics Canada's "universal crime disclosure" manual, the police force is supposed to flag changes, not the other way around.

Why accurate reporting matters

When it comes to hate-crime reporting, Perry considers Toronto's police force to have set the "gold standard."

Its figures on hate-related incidents closely match those released by StatsCan. The largest discrepancy occurred in 2017, when Toronto police reported 186 incidents, compared to 221 by the statistics agency.

Without addressing the difference in 2017, Toronto police hate crime investigator Det. Const. Kiran Bisla attributed the discrepancies to how investigations unfold over time.

"Sometimes what is initially filed as a hate-motivated occurrence, upon further investigation, is deemed not to be motivated by hate," said Bisla.

"There may have been a different motivation, and vice versa."

Bisla said hate crimes are already under-reported and can lead to "stress and isolation" if police don't respond quickly and appropriately.

Quebec Islamic Cultural Centre president Boufeldja Benabdallah. The mosque was the scene of a suspected hate crime earlier this year. A man allegedly assaulted a Muslim man in the parking lot. (Jacques Boissinot/Canadian Press)

"Hate crimes differ from other types of criminal offences because they are message crimes. The message is 'you are not welcome,'" she said.

Bisla added that tracking numbers accurately is "extremely important" for two reasons.

One, it helps police respond more effectively. And two, communities need to be aware if they are being targeted more frequently.

Perry said that without accurate hate-crime reporting, it is difficult for authorities to address the problem.

She said it is also a way for targeted communities to have their concerns heard by a larger audience.

"They want (the number of hate crimes) publicized so that the rest of us understand and recognize the challenges that face those communities," said Perry.