New research confirms what many NHL hockey fans have long suspected, that referees consistently call more penalties on visiting teams.
In a sampling of more than 2,300 power plays from Jan. 1 through mid-February, home teams had 11.5 per cent more man advantages than did visitors.
National Hockey League teams have won 55 per cent more points and games at home than on the road this year - a statistic which fits nicely into the 54- to 56-per-cent advantage home teams have enjoyed throughout this decade.
Is it because of familiarity? Comfort? The last line change?
Perhaps. But there may be another more significant factor. Research by The Edmonton Journal and Vancouver researcher Will Lockwood shows that referees consistently award more power plays to the home teams.
The 11.5 per cent figure surprised everyone interviewed, including former referees Lance Roberts and Mark Faucette, former linesman Swede Knox and such coaches as the Vancouver Canucks' Alain Vigneault.
"I'm surprised it's that much," Vigneault said when presented with the numbers.
He shouldn't be. Last year - according to statistics compiled by Lockwood - Vancouver had the biggest home/away power-play advantage. The Canucks had an average of 5.17 power plays at home compared with an average of 3.83 power plays on the road.
The Edmonton Oilers were near the bottom, receiving slightly more power plays on the road (an average of 4.24 per game) than at home at Rexall Place (4.15 per game).
Overall, it's not just this year or last year that NHL home teams got more power plays, it has happened to every team throughout this decade.
The Phoenix Coyotes are the biggest recipients of home power plays this decade - garnering an average of 1.22 more man-advantages than visiting teams. The Canucks are second.
The bigger question, of course, is why home teams consistently get more power plays than road teams.
"Eleven per cent is a lot," said Calgary Flames head coach Mike Keenan. "That's the officials being influenced . . . whether they would consciously agree - probably not - but subconsciously it's a fact.
"I think crowd support sometimes biases the calls that are made on the ice, which is normal and natural."
Dr. Patrick Keelan, a registered psychologist from the Calgary Counselling Centre, says a lot of that bias is due to learned behaviour.
"If a referee is in a position to make a call, they will usually have to make a quick decision with little time to think," said Keelan, an avid sports fan who has studied the subject of home advantages. "And when you are making quick decisions you rely on heuristics - mental cues or mental rules of thumb," he said.I
"Say there is an aggressive play. If the visiting team commits it, one of the cues the referee may call on may be crowd noise."
Generally, when a home-team player is tripped or fouled, the crowd will yell. But if a visiting player is tripped or fouled, the noise is muted.
"Subconsciously, referees often associate calling a penalty with crowd noise and crowds getting irate," said Keelan.
That cue is more likely to be in the referee's mind when there is a perceptional explanation that the crowd noise is not going to be there."
Keelan said another behavioural factor is consequence.
"One of the basic principles of psychology is people will repeat behaviours that get them positive consequences and are less likely to repeat behaviours that result in negative consequences."
An experiment conducted by Paul Ward, a cognitive psychologist at Florida State University, seems to bear this out.
Ward attached EKGs to a group of soccer referees, players and coaches and asked them to call penalties. Half the test group watched the games with crowd noise, the other half with the sound muted.
Ward's research showed that those who had crowd noise as a cue called 21 per cent fewer fouls on the home team.
Stephen Walkom, a former NHL referee who is now the NHL's director of officiating, doesn't buy that analysis of the research numbers.
"You don't hear the crowd," said Walkom. "When you are in the zone, you are focused only on hearing what you have to be focused on - like a coach nodding his head for a line change," he added.
"When you are officiating minor hockey, you hear everything. You hear the obnoxious coach, the obnoxious player and the obnoxious parent. But the higher up you go and the more people there are in the building - that buzz you don't even hear."
In fact, Walkom said there is only one time referees hear the crowd.
"And I shouldn't really be telling you this, but it's when the game is over. Mentally it's over. Mentally you have disarmed yourself. Only now do your senses pick up the crowd."
So why this rather large discrepancy between penalties called on the visitors and those against the home team?
"I think it's more about the players than it is about the referees," said Walkom. "I think there is more conscious pressure on the players to play better and harder in front of their home crowd than what affects the referee."
Players are conditioned early on that playing at home is our ice and that nobody beats us in our house."
Vigneault, Edmonton Oilers head coach Craig MacTavish and former NHL referee Lance Roberts agreed with Walkom.
"The home team usually plays at a higher level and that causes the visiting team to take penalties," said Roberts.
"Sure, there are still human elements that get involved and, in the heat of the moment, maybe you get caught up sometimes.
"When I officiated some of those playoff games between Dallas and Edmonton, you could feel the atmosphere as soon as you got to Edmonton. And Philadelphia could be hostile.
"But I thrived on that. You couldn't wait to get a game like that."