Champion Data Averages and Round 17: Richmond v Fremantle

Champion Data has a contract with the AFL to provide statistics for every player and team for every match played during the Home and Away and Finals series, with the data being provided to the AFL and published publicly here. This data is no doubt used for a number of purposes, one of them being the creation of player ratings.

These player ratings interest the Poll Way, as they purport to describes the relative performances of players in any given game, and to build a score for players based on their performances over the past 40 rounds. If these ratings are accurate over the course of a season, then it might be possible to build a model to predict the outcomes of matches come finals time. A full explanation of how player ratings work can be found here.

For the purposes of a very simple initial investigation of this idea, for this week the Poll Way is going to pretend that Round 17 is a finals round. As of the start of Round 17, the top 8 teams on the ladder are Collingwood, Essendon, Fremantle, Geelong, Hawthorn, Port Adelaide, Richmond and Sydney. Only matches between these teams to date during the 2013 season will be included to develop team ratings. Matches with the bottom 10 teams won’t be used, as the Poll Way takes the view that there’s no point in including Jobe Watson’s performance against, say, Melbourne, as it will have little to no bearing on how Essendon will do against a true finals contender.

There have been 25 games played between these 8 teams so far in 2013. The Poll Way has taken the player ratings for each player in each match and averaged them to provide a team score for every match. Theoretically, the team with the higher rating should be the team that won. The table below shows that this isn’t always the case.

HOME   TEAM

AWAY   TEAM

WINNER

HIGHEST   MATCH RANKING

Hawthorn

Geelong

Geelong

Hawthorn

Collingwood

Hawthorn

Hawthorn

Hawthorn

Fremantle

Essendon

Essendon

Fremantle

Richmond

Collingwood

Collingwood

Collingwood

Hawthorn

Fremantle

Hawthorn

Hawthorn

Sydney

Geelong

Sydney

Sydney

Essendon

Collingwood

Essendon

Essendon

Fremantle

Richmond

Fremantle

Fremantle

Richmond

Geelong

Geelong

Geelong

Fremantle

Collingwood

Fremantle

Collingwood

Geelong

Essendon

Geelong

Essendon

Hawthorn

Sydney

Hawthorn

Hawthorn

Port Adelaide

Richmond

Richmond

Richmond

Collingwood

Geelong

Collingwood

Collingwood

Sydney

Fremantle

Sydney

Sydney

Collingwood

Sydney

Sydney

Sydney

Richmond

Essendon

Essendon

Essendon

Port Adelaide

Geelong

Geelong

Geelong

Sydney

Essendon

Sydney

Sydney

Port Adelaide

Sydney

Port Adelaide

Port Adelaide

Port Adelaide

Collingwood

Port Adelaide

Port Adelaide

Geelong

Fremantle

Geelong

Geelong

Essendon

Port Adelaide

Essendon

Essendon

Geelong

Hawthorn

Geelong

Geelong

Port Adelaide

Hawthorn

Hawthorn

Hawthorn

The above table is a bit difficult to navigate, but in short it shows that generally high Champion Data match rankings accord with match wins. There are 4 occasions where it doesn’t work out like that though, namely Hawthorn v Geelong, Fremantle v Essendon, Fremantle v Collingwood and Geelong v Essendon.

There is another way to use the collected data to create a metric of team performance, which is to average the match rankings of individual players over the course of the relevant matches and then average the scores of the 22 players who were selected for a given match. These results are given below.

HOME   TEAM

AWAY   TEAM

WINNER

HIGHEST   AVERAGE RANKING

Hawthorn

Geelong

Geelong

Hawthorn

Collingwood

Hawthorn

Hawthorn

Hawthorn

Fremantle

Essendon

Essendon

Essendon

Richmond

Collingwood

Collingwood

Collingwood

Hawthorn

Fremantle

Hawthorn

Hawthorn

Sydney

Geelong

Sydney

Sydney

Essendon

Collingwood

Essendon

Essendon

Fremantle

Richmond

Fremantle

Fremantle

Richmond

Geelong

Geelong

Geelong

Fremantle

Collingwood

Fremantle

Collingwood

Geelong

Essendon

Geelong

Geelong

Hawthorn

Sydney

Hawthorn

Hawthorn

Port Adelaide

Richmond

Richmond

Richmond

Collingwood

Geelong

Collingwood

Geelong

Sydney

Fremantle

Sydney

Fremantle

Collingwood

Sydney

Sydney

Collingwood

Richmond

Essendon

Essendon

Essendon

Port Adelaide

Geelong

Geelong

Geelong

Sydney

Essendon

Sydney

Essendon

Port Adelaide

Sydney

Port Adelaide

Sydney

Port Adelaide

Collingwood

Port Adelaide

Collingwood

Geelong

Fremantle

Geelong

Geelong

Essendon

Port Adelaide

Essendon

Essendon

Geelong

Hawthorn

Geelong

Hawthorn

Port Adelaide

Hawthorn

Hawthorn

Hawthorn

Oh dear… All of a sudden there are 9 games where the winner is not the team with the highest ranking.

However, each of these 9 games can be placed in one of three different categories:
1. Matches with Collingwood
2. Matches with Sydney
3. Matches between Geelong and Hawthorn

Where the results of matches with Collingwood and Sydney are inconsistent with the average rankings, Collingwood has a tendency to lose matches it shouldn’t, while Sydney has a tendency to win matches it shouldn’t.

While the Poll Way doesn’t necessarily have an explanation for this, it does suggest that Collingwood and Sydney have considerable inconsistencies between their ability to get hold of the ball, and their ability to score. Collingwood have an excellent midfield capable of cutting through most other teams, yet their forwards aren’t necessarily able to convert. Conversely, Sydney appears to be able to score efficiently, perhaps due in part to their now famous ‘slingshot’ off the half-back line which can deliver coast to coast goals while racking up few stats.

As for games between Geelong and Hawthorn, well, Geelong did promise that they’d never lose another game to Hawthorn again. The Kennett curse is alive and well (but then again, we already knew that).

Now, all this numberin’ wouldn’t be any fun unless we tried to predict something so we can get it wrong or right. Given that the Poll Way is pretending that round 17 is the finals, and that there is only one match between top 8 sides this week, we will look at that match: Richmond v Fremantle.

Using the method described for the second table above, Fremantle has an average player rating of 69.7, while Richmond’s score is 67.9. Two players who will be in this match have not played a game against another top 8 side this year so far, namely Aaron Sandilands for Fremantle and Matthew Arnot for Richmond. Both of these players have been assigned a score of 0 by the Poll Way for the purposes of this analysis. This is of course inaccurate, however with all due respect to Mr Arnot, Sandilands will probably have a greater positive impact on the game. Sandilands’ true score is likely greater than Arnot’s, so the fact that they have both been assigned a score of 0 and Fremantle still has a higher overall rating than Richmond means that there is no overall change to the two teams’ relative rankings. By these numbers, despite Pavlich and Ballantyne being significant outs for Fremantle, they should still get up over Richmond.

Then again, anything can happen on the day.