www.foxsports.com.au/afl/st-kilda-coach-...167a0c392ddf80ff3810
"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."