Matter of Stats

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2015 - Team Ratings After Round 20

ChiPS jiggled the Rankings of another four pairs of teams this week, swapping the Roos and Freo in 4th and 5th, the Dogs and Pies in 7th and 8th, the Crows and Cats in 9th and 10th, and the Saints and Dees in 13th and 14th. More a light dusting than a clean-out-your-garage kind of weekend.

ChiPS Number 1 Rated team, Hawthorn, allowed West Coast to shave about 1 Rating Point (RP) off their lead this weekend but still enjoy more than a 15 point gap over the Eagles who, in turn, are Rated about a 9 RP better team than the Tigers, who sit 3rd. Reflecting the closeness of the mid-pack competition this year, nine teams retain Ratings above 1,000, with the Cats just 1 RP below that mark.

Amongst the highest-Rated teams, the Roos and the Dogs have the most impressive cuurent form, both having accumulated RPs in each of the last six rounds. Fremantle's form is poorest, they having shed RPs in 10 of their last 11 starts, though Sydney's is not a great deal better, they having shed RPs in 7 of their last 8 games.

(As usual, a full version of this table appears at the end of the blog.)

MoS' other main Team Rating System, MARS, re-Ranked seven teams this weekend, dropping the Cats three places into 9th to allow Richmond, the Western Bulldogs and Adelaide to each climb one spot, and lifting the Saints up two places after dropping Melbourne and Gold Coast by one spot each.

Just two teams remain Ranked more than two places differently by ChiPS and MARS:

  • Richmond, Ranked 3rd by ChiPS and 6th by MARS
  • Collingwood, Ranked 8th by ChiPS and 11th by MARS

That leaves the rank correlation between ChiPS and MARS Team Rankings at +0.959, and between ChiPS and MARS Team Ratings at +0.968.

COLLEY, MASSEY AND ODM

Colley this week also re-Ranked seven teams, though only Geelong by more one spot, they being shunted down two places to 9th. Massey re-Ranked eight teams, most notably lifting Adelaide by three places into 7th, dropping Collingwood two places into 9th, and dropping Geelong two places into 10th, while ODM also re-Ranked eight teams, like Massey moving the Crows up three places into 7th, but this its only multiple-spot move.

Those moves leave Massey and ODM as the pair of Systems with the most similar Team Rankings, the rank correlation between their opinions remaining at +0.996. ChiPS and Colley still have the lowest rank correlation, though it is up a little this week to +0.930. The overall picture across the Systems remains one of broad agreement, as the following chart depicts.

ChiPS remains the System with Team Rankings most different from the competition ladder (rank correlation +0.932, up from +0.926), while Colley remains the System with Team Rankings most similar to the competition ladder (+0.988, up from +0.986).

ODM DEFENSIVE AND OFFENSIVE RANKINGS

There was no change this week in ODM's Top 5 Defensive Teams, which remain:

  1. Fremantle
  2. Hawthorn
  3. West Coast
  4. Sydney
  5. Richmond

The Western Bulldogs still sit 6th on Defence, though Collingwood has now moved up into 7th.

ODM did, however, slightly change the ordering, if not the membership, of its Top 5 Offensive Teams, which are now:

  1. Hawthorn (no change)
  2. West Coast (no change)
  3. Adelaide (up 1)
  4. Kangaroos (down 1)
  5. Western Bulldogs (no change)

Port Adelaide have now assumed 6th position, relegating Collingwood to 7th.

With the weekend's changes, ODM's and MoSSBOD's Rankings have moved into better alignment, the rank correlations now:

  • For Defence +0.942
  • For Offence +0.942
  • Combined +0.940

Only for Fremantle and Richmond are there now disagreements about rankings that exceed three places, ODM Ranking Freo four places higher on Offence, Defence and Overall, and Ranking Richmond four places lower on Offence.

Looking solely at MoSSBOD Ratings for a moment, note that a number of the pursuing teams lifted their Ratings significantly nearer Hawthorn's this week, West Coast getting 0.33 Scoring Shots nearer, the Dogs getting 0.95 Scoring Shots nearer, Richmond getting 0.68 Scoring Shots nearer, and Adelaide getting 1.09 Scoring Shots nearer. Hawthorn remains, however, about an 0.8 Scoring Shots better team than any other in the competition, assessed at a neutral venue. At an assumed 3.65 points per Scoring Shot, that's makes MoSSBOD's estimate of Hawthorn's superiority over West Coast far smaller than ChiPS'.

PREDICTIVE ACCURACY

No System out-tipped MARS this week, though ChiPS and Massey did match MARS' performance. That leaves:

  • ChiPS tied with MARS
  • Colley 21 tips behind MARS (down 2)
  • Massey 11 tips behind MARS (no change)
  • ODM 11 tips behind MARS (down 1)
  • The Offensive Rating Component of ODM 7 tips behind MARS (down 1)
  • The Defensive Rating Component of ODM 18 tips behind MARS (down 1)

FULL ChiPS AND MARS TABLE