2013 : MARS, Massey, Colley and ODM Ratings After Round 10

All the MARS action was mid-table again this week, with the teams Ranked 5th through 9th the only ones to move. The Blues and the Roos each jumped three places while the Eagles fell 3, the Dons 2, and the Crows 1 spot.

Those moves leave the Roos as the team with the largest difference between Ladder position and MARS Ranking. They're now Ranked 6 spots higher by MARS than their Ladder position would warrant, their MARS Rating far better reflecting the narrowness of so many of their losses this season. Three other teams have 4 spot differences between Ladder and MARS: Essendon (5th on the Ladder but 9th on MARS), Richmond (7th on the Ladder but 11th on MARS), and St Kilda (16th on the Ladder but 12th on MARS). MARS seems to have been holding out hope for a return to the Saints' glory days for far longer than is necessary.

Turning our attention to the last 5 rounds we find that 10 teams have accrued Ratings Points (RPs) over that period, 9 of which now fill the top 9 spots on MARS Ranking, and the 10th of which, the Gold Coast, currently sits in 15th. Geelong, Carlton, the Roos and Hawthorn have been the biggest RP accruers across this period, and St Kilda, the Dogs, Melbourne and GWS the biggest RP shedders.

Agreement about the respective ranking of the teams by the various Rating Systems used on MAFL is now almost unanimous. Only Colley with its particularly jaundiced view of the Crows and the Roos, and with its rose-coloured view of the Pies, stands out as being different to any meaningful extent.

A look at the component Rankings of ODM reveals that Adelaide, Fremantle, Port Adelaide and Sydney are assessed as having defences significantly more-highly ranked than their respective offences, and that Collingwood, Geelong, the Roos and Carlton have the opposite.

ODM's Ranking of Collingwood's offence as the 5th-best in the competition seems a little odd when you note that they've scored fewer points this season than 10 of the other teams in the top 12 positions on the competition ladder, but is made a little more believable by acknowledging that exactly one half of their games have been against Fremantle, Geelong, Hawthorn, Sydney and Carlton, all of which teams have offences that are highly-rated by ODM.

MARS continues to be the Rating System with the best predictive accuracy, Massey the second-best, and the Offensive component of the ODM System third-best - ahead even of the ODM System's combined Offensive and Defensive components, which lies 4th.

The Colley System continues to lag all other Systems, including the Defensive component of the ODM System alone. There's something about ignoring teams' margins of victory and defeat that appears to reduce predictive accuracy.

Finally, here's the track of the MARS Ratings for every team over the course of the season so far:

What strikes me about this chart is how many of the teams display medium- to longer-term trends in their Ratings rather than exhibiting significant short-term ups and downs. Collingwood, Richmond and Sydney are the most obvious exceptions to this.