When a player takes a shot at goal, Champion Data also records the player’s position on the ground and how much pressure they are under.
For instance, Richmond kicked 19.9 (123) against Essendon in Perth last weekend – the club’s second-highest score of the year. But based on the difficultly of the shots at goal the Tigers took, they were ‘expected’ to kick 106.5 points for the game, meaning they exceeded accuracy expectations.
It can work the other way, too. In the same game, Essendon finished with 12.12 (84). But according to Champion Data’s expected accuracy formula, the Bombers should’ve kicked 101.3 points.
While the Tigers won the match by 39 points (123-84), the margin should’ve been a lot closer according to the expected scores (106.5 to 101.3).
This is why teams use expected score. Tigers coach Damien Hardwick would’ve left Optus Stadium sensing his side didn’t perform as well as the scoreboard suggested. It helps teams avoid complacency when, if they simply looked at the margin, they might think all is well.
https://www.foxsports.com.au/afl/where-every-club-ranks-in-the-2021-expected-accuracy-ladder-champion-index/news-story/001a4914d94d2a07907973ee3376bcdf