2013 : MARS, Massey, Colley and ODM Ratings After Round 15

Action on the MARS Ratings ladder this week was all at the top, as eight of the ten highest-ranked teams changed places while none of the eight lowest-ranked teams moved at all.

Amongst the eight moves were three falls, the most precipitous of which were Richmond's and Carlton's. Both fell three places on the back of sizeable losses to less-fancied opposition. Sydney was the only other team to descend, which it did despite winning, but by a margin insufficiently large to justify its pre-game Ratings dominance over the Dees.

Of the five teams climbing the ladder, only one ascended by more than a single rung. That team was the Roos, who now find themselves in 5th spot despite lying 10th on the competition ladder. This five spot difference between MARS and competition ladder ranking is the highest for any team, exceeding the four spot difference for Port Adelaide (12th on MARS and 8th on the competition ladder), and the three spot differences for the Dons (6th and 3rd) and the Saints (13th and 16th). No other team's MARS and competition ladder rankings differ by more than two places, and six teams have identical rankings in each.

Looking back over the most recent five rounds it's striking that the teams now ranked 1st to 8th on MARS have accumulated points over that period while none of the teams ranked 9th to 18th, Port Adelaide aside, have managed to do likewise. This phenomenon has served to steadily lengthen the interquartile Rating Point (RP) difference - the difference in MARS Rating between the team ranked 4th and the team ranked 15th - driving it up to a season-high 50 RPs this week.

At the same point last season the difference stood at 54.1 RPs before rising over the remainder of the home-and-away portion of the year to finish at 71.8 RPs. Let's hope we don't see a blow out like that again this season.

Widening our attention to take in the views of the other Ratings Systems we find that agreement still reigns with only the Roos, Port Adelaide and St Kilda generating any significant debate.

For all three of those teams it's MARS and Colley that hold the most extreme opinions and so define the gap. MARS also ranks Essendon and the Gold Coast notably lower than does it peers, while Colley ranks Collingwood higher and Sydney lower than does its peers. ODM's and Massey's rankings don't much stand out for any of the teams.

ODM's opinions have not changed much on the basis of last weekend's results, though some of the established trends in its assessments have been reinforced, most notably for Adelaide (down), Carlton (down), Collingwood (up), the Roos (up), Richmond (down), and the Dogs (down).

MARS continues to provide the most accurate simple predictions of game outcomes, based solely on selecting as the winning team the higher Rated of the combatants. Across all the Systems the ordering in terms of predictive accuracy that was established a few rounds back still prevails: MARS lead Massey followed by ODM and then its two component ratings, with Colley in last place.

It's still also the case that teams' relative ODM Offensive Ratings are better predictors of a game outcome than the teams' relative ODM Defensive Ratings.

The broadly trending nature of teams' season-long MARS Ratings is still the most recognisable feature of the MARS Rating chart.