Domestic violence calls in Calgary jump when the Stampeders take the field — but only when the CFL team takes on its arch-rival, the Edmonton Eskimos, or when the team plays in the Grey Cup, according to a new study.

Hockey didn't seem to have an impact on domestic violence calls in the city, even when the Calgary Flames faced off against the Edmonton Oilers, according to the study, The Connection between Professional Sporting Events, Holidays and Domestic Violence in Calgary, Alberta, released Thursday by the University of Calgary's School of Public Policy.

Calls also spike on the seventh, ninth and tenth days of the 10-day Calgary Stampede, according to the study, which found a "statistically significant" change in domestic violence reports during certain sporting events and holidays.

"Rather than trying to apply a single theory to these findings, we need to determine how and why domestic violence is happening," said study co-author Lana Wells, with the University of Calgary's faculty of social work. "Our approach is to look at where domestic violence is the worst and intervene to prevent it."

Alberta has the fourth-highest rate of police-reported domestic violence for a Canadian province, according to the study, which analyzed four years of daily phone calls made from the public to the Calgary Police Service and the "Connect" service — a specialized phone line for people experiencing domestic violence.

From Jan. 1, 2011, to Dec. 31, 2014, nearly 70,000 calls reporting domestic violence were made in Calgary.

Researchers then went back and analyzed the data to determine which variables — like time of year, weather, special events and economic stress — seemed to correlate with higher domestic violence reports in the city.

Domestic violence patterns

The study identified certain patterns in Calgary's domestic violence reports.

On game days when the Stampeders played the Eskimos, the number of domestic violence calls were 15 per cent higher than the average, researchers said.

The level of contact or violence in the sport is not as important as the rivalry or the high stakes of the games. - Lana Wells, study co-author

The median number of calls on the average day is 47, the study says.

The study also examined days when significant sporting events were held — like Ultimate Fighting Championship matches and the Super Bowl — and did not find any significant increase in domestic violence calls on those days.

"The non-relationship between Ultimate Fighting Championship and domestic violence rates suggests that the level of contact or violence in the sport is not as important as the rivalry or the high stakes of the games that we found to be significant with the Stamps playing in the Grey Cup or against the Edmonton Eskimos," Wells said.

Domestic violence calls were 40 per cent higher than average on the day after the Grey Cup game in 2012, which the Stampeders lost, and 2014, which they won, according to the study.

While the study found no spike in reports during hockey games, researchers were unable to test whether domestic calls spiked during playoff hockey, as the Flames didn't participate in playoffs during that period.

The Flames played 295 games during the course of the study, while the Stampeders played 87.

The study also identified other patterns in domestic violence reports, including that:

Calls were 30 per cent higher on weekends compared to the rest of the week.

Calls were 10 per cent higher during summer months.

Calls spiked during certain holidays — New Year's Day, Good Friday, Canada Day, Easter, Labour Day, Valentine's Day and the day after Halloween.

It's disturbing to see a spike in domestic violence on public holidays, but the Calgary Stampeders and the Canadian Football League are committed to help stopping domestic violence, said Calgary Stampeders Coach and GM John Hufnagel.

"We have been and we will continue to be partners with the Alberta Council of Women's Shelters," he said.

"We have players going through three full days to get themselves prepared to make community appearances to spread the message. The league has a initiative that all players and staff have to go through a domestic violence seminar. We promote it during the games with public service announcements, signage. It's even on our website."

Hufnagel invited researchers to call him if they have ideas about more the organization can do to help.