Matter of Stats

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2015 - Team Ratings After Round 11

With just six games over the weekend, wholesale changes in team Rankings seemed unlikely and, in the end, ChiPS re-Ranked only three team and MARS re-Ranked seven.

ChiPS reshuffled only the teams in positions 9 through 11, promoting Adelaide (who didn't play) and Essendon (who played and lost) each by a spot into 9th and 10th respectively, both teams beneficiaries of Port Adelaide's slide into 11th place after ChiPS stripped them of 3.1 Rating Points (RPs) based on the unexpected magnitude of their loss to the Cats.

West Coast, who remain second, narrowed the gap to the Hawks this week after grabbing 1.2 RPs from Essendon in their 50-point victory.

The Eagles also accumulated MARS RPs, enough in fact for them to take 3rd spot from Fremantle, who shed RPs despite winning their game against the Suns. It's quite rare on MARS for a team to win yet surrender RPs, but the narrowness of Freo's victory set alongside the massive RP advantage they took into the game was enough to convince MARS to take this relatively unusual action.

Other teams to move on MARS were Geelong (up 2 places), Collingwood and the Gold Coast (both up a single place), Port Adelaide (down 3 places), and Carlton (down a single place).

The correlation between ChiPS and MARS Team Ratings now stands at +0.972 and between ChiPS and MARS Team Rankings +0.934 with the largest differences in Rankings being for:

  • Richmond, Ranked 5th by ChiPS and 9th by MARS
  • Kangaroos (7th and 10th)
  • Port Adelaide (11th and 8th)
  • Gold Coast (17th and 14th)

COLLEY, MASSEY AND ODM SYSTEMS

Colley, Massey and ODM were each more like MARS than they were like ChiPS in terms of team re-Rankings this week, Massey re-Ranking seven teams, Colley eight, and ODM re-Ranking 11 teams.

Colley's most dramatic change was for the Cats, which it elevated from 12th to 8th, with no other team moving by more than two places under this System. Massey, similarly, moved the Cats most, in its case lifting them from 11th to 6th. It also dropped GWS three places from 8th to 11th, however, and Port Adelaide three places from 5th to 8th.

ODM lifted Geelong from 11th to 7th, and the Pies from 8th to 5th, while dropping GWS from 7th to 10th, and Port Adelaide from 6th to 9th.

The lowest rank correlation between the Team Rankings of any pair of Rating Systems still belongs to Colley and MARS. It stands at +0.810 (up from +0.773 last week). Next-lowest is the correlation between Colley and ChiPS at +0.843 (up from +0.812).

The two highest correlations are between Massey and ODM (+0.986, down from +0.990), and between ChiPS and MARS (+0.934 as mentioned earlier, up from +0.926).

Looking, instead, at the rank correlations between the Team Rating Systems and the competition ladder yields the following:

  • Colley and Ladder +0.977 (up from +0.971)
  • ODM and Ladder +0.891 (down from +0.893)
  • Massey and Ladder +0.880 (down from +0.889)
  • MARS and Ladder +0.841 (down from +0.847)
  • ChiPS and Ladder +0.841 (down from +0.843)

The largest differences (minimum four places) between the Rankings and ladder positions relate to:

  • Adelaide, Ranked 11th by ODM; 7th on the ladder
  • Gold Coast, Ranked 14th by MARS; 18th on the ladder
  • GWS, Ranked 10th by ODM, 11th by Massey, and 12th by ChiPS and MARS; 5th on the ladder
  • Hawthorn, Ranked 1st by ChiPS, MARS, Massey and ODM; 6th on the ladder
  • The Kangaroos, Ranked 7th by ChiPS, 12th on the ladder
  • The Western Bulldogs, Ranked 6th by ODM; 10th on the ladder

ODM COMPONENTS

This week sees some reordering of ODM's Top 5 Defensive Teams:

  1. Hawthorn (up from 4th)
  2. Fremantle (down from 1st)
  3. Sydney (down from 2nd)
  4. West Coast (down from 3rd)
  5. Richmond (no change)

Clearly, for the Hawks, not playing has its advantages.

ODM's Top 5 Offensive team list has changed too, but more substantially:

  1. West Coast (up from 2nd)
  2. Hawthorn (down from 1st)
  3. Kangaroos (up from 5th)
  4. GWS (up from 7th)
  5. Collingwood (up from 10th)

Nine teams are now significantly differently Ranked by ODM in terms of Offensive and Defensive strength. Five are Ranked much more highly for their Defence:

  • Adelaide (Ranked 6th on Defence, 12th on Offence)
  • Essendon (9th and 15th)
  • Fremantle (2nd and 7th)
  • Richmond (5th and 13th)
  • Sydney (3rd and 8th).

Four others are Ranked more more highly for their Offence:

  • Geelong (Ranked 6th on Offence, 11th on Defence)
  • GWS (4th and 12th)
  • The Kangaroos (3rd and 13th)
  • St Kilda (11th and 18th)

PREDICTIVE ACCURACY

ChiPS predicted one more winner than MARS this week and so has drawn level with MARS in terms of winners predicted since the season began.

Colley predicted one result fewer than MARS and so now trails by 14 tips, as did ODM, which now trails by eight. Massey and the Offensive Component of ODM each tipped the same number of correct results as MARS to remain eight tips behind, while the Defensive Component of ODM also tipped the same number of correct results as MARS to remain nine tips behind.