This week saw a surprisingly high level of team re-Ranking on both the ChiPS and the MARS Rating Systems, nine teams moving house on ChiPS, and 12 doing the same on MARS. For both Systems, the majority of these moves came from teams now Rated in the 990 to 1,010 "near-average" range, a range that's more congested this year than last. At the end of Round 7 in 2014, MARS Rated only six teams in that range and ChiPS Rated only four; this year the equivalent counts are nine for ChiPS and eight for MARS.
On ChiPS, the Tigers were the big climbers this week, up two places into 7th after snatching just under 2 Rating Points (RPs) from the Pies after their unexpected 5-point victory. Four other teams climbed by a single place: the Eagles into 2nd, the Roos into 5th, the Dons into 6th, and the Saints into 15th.
Four teams were also demoted by ChiPS, Port Adelaide falling furthest in tumbling three places into 8th.
ChiPS' Top 4 teams are now Rated more than 16 points better on a neutral ground than any other team in the competition. After them, just 4.5 RPs separates 5th from 10th, another manifestation of the crowded nature of team Ratings alluded to earlier.
MARS this week also had just a single team climbing multiple places (the Lions, up two places into 16th) and a single team falling multiple places (the Dees, down two places into last), but it down-Ranked five other teams and up-Ranked five more.
At the end of all the shuffling, ChiPS and MARS team Rankings are now most different for:
- Essendon, Ranked 6th on ChiPS and 11th on MARS
- Richmond, 7th and 10th
- Adelaide, 10th and 5th
- Melbourne, 14th and 18th
- Gold Coast, 17th and 14th
The two Systems do, however, still have highly correlated team Ratings (+0.97) and agree on the competition's four best teams, though they quibble a little about the correct ordering.
Colley, Massey and ODM
If we canvass the opinions of MoS' other Team Rating Systems - Massey, Colley and ODM - about the five teams where ChiPS and MARS Rankings differ most, we find that they support MARS' Rankings of Adelaide and Essendon, and support ChiPS' views of Gold Coast and Melbourne. They disagree with both ChiPS and MARS, however, about the appropriate Ranking of Richmond, which they think should be Ranked 13th or 14th, lower even than MARS' Ranking of 10th.
Colley has its own opinions about the Ranking of two teams in particular: Collingwood, which it Ranks 12th, two places lower than any other System, and Hawthorn, which it Ranks 7th, five places lower than any other System. For the Colley System, Ratings are all about winning and losing, about who you defeat and who you are defeated by, so the Hawks' and Pies' 4 and 3 records count against them especially, in the Pies' case, when the defeats include losses to the teams Colley Ranks 10th and 14th (Geelong and Richmond) and, in the Hawks' case, losses to the teams it Ranks 9th and 11th (Port Adelaide and Essendon).
ODM Team Offensive and Defensive Rankings
Only three teams are this week Ranked by ODM more than four places differently for their Offensive skills than for their Defensive skills:
- Essendon, Ranked 4th on Defence and 16th on Offence
- The Kangaroos, 14th and 7th
- Melbourne, 11th and 18th
A quick look at the current Team Dashboard helps explain why these Rankings are what they are. There we find that:
- Essendon have the best (ie lowest) Opponent Scoring Shot Conversion rate in the competition, but also have the 3rd-worst rate of Own Scoring Shot Generation
- The Kangaroos are 6th-best for Own Scoring Shot Generation and Conversion, but 12th for Opponent Scoring Shot Generation
- Melbourne are 12th for Opponent Scoring Shot Conversion, but 18th for Own Scoring Shot Generation
SIMPLE PREDICTIVE ACCURACY
MARS continues to lead all-comers in the simple predictive accuracy race, having Rated winning teams higher than losing teams on two more occasions than ChiPS. It's also done the same thing on seven more occasions than Massey, ODM and the Offensive component of ODM, on 10 more occasions than the Defensive component of ODM, and on 12 more occasions than Colley.
No System out-predicted MARS this week, and Colley, Massey and the Defensive component of ODM predicted one result fewer. Excluding Round 1, for which all Systems were credited with 4.5 correct tips from 9 since some Systems had no Ratings at that point, MARS has correctly identified the winner in 37 of 54 contests, a 68.5% accuracy rate. (If we include MARS' actual Round 1 performance this becomes 43 from 63, a 68.2% accuracy rate, which matches the accuracy of the TAB Bookmaker so far this season.)