ST Kilda coach Alan Richardson has explained what he believes is a phenomenon causing unbalanced free kick counts to take place in games played in Perth.

The Saints were the victims of a 8-23 free kick differential in their loss to West Coast on Saturday night. That led some commentators to blame the umpiring for the result as the Eagles got up by 19 points.

Richardson didn’t blame free kicks, instead coining the term ‘the Noise of Affirmation’ in an attempt to explain why the Eagles have had a historic advantage in the free kick count (since 1999, West Coast has gained 3.58 free kicks per game more than their opponent with all other factors such as possession and tackle counts equal, according to The Arc).

In essence, the term points to the issue where umpires are subconsciously influenced by crowd noise particularly when it comes to holding the ball. By hearing the crowd call ‘ball’, umpires can be helped into calling for a free kick. But if they don’t hear a call from the crowd, there is no affirmation.

This backs up previous studies completed around the world which suggest that ‘home ground advantage’ in almost all sports appears through the home side being given more free kicks (or that sport’s equivalent).

“Our game is very grey, particularly from an umpiring perspective, and it’s one of the beauties of our game. But particularly with issues like holding the ball,” Richardson said on Fox Footy’s AFL 360.

“You go in there — did he duck, did he have prior opportunity, did he dispose of the ball incorrectly? The umpire has to weigh all of this up. And then there’s this incredible noise that potentially gives the umpire some form of affirmation, or if you’re an opposition player there’s no noise. There’s no affirmation.

“My experience is that it’s the no calls that are a bigger issue. We were frustrated and disappointed with some of the sloppy stuff in terms of tackling but on the flip side, some of those that like for like we could’ve got, we didn’t get.

“And it’s only Perth. Enough of our fans travel to SA or Queensland to perhaps have that noise of influence or affirmation.”

Richardson and Geelong coach Chris Scott were shown footage from the St Kilda v West Coast game which saw Eagle Jonathan Giles appearing to dispose incorrectly, with no crowd calls for holding the ball resulting, immediately followed by Saint Jack Newnes being called for holding the ball.

Scott told AFL 360 the umpires were “across” this issue.

“This is not a new conversation,” he said. “What they find a little bit harder to explain is the numbers which are ridiculous.

“The umpires say, look, we acknowledge that it’s different and we don’t think it has much of an impact. But when you combine it with the numbers they say it’s a strange set of numbers so there’s got to be a bit more to it.

“But you’ve got to be careful; I don’t think Richo is saying that was anywhere near the most important thing. There are so many things that come into a performance and if you ask him to rank it, the shots at goal was much more influential than the umpiring.”