Matter of Stats

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2019 - Team Ratings After Round 10

GWS did enough this week to retain its number 1 ranking on MoSSBODS and MoSHBODS, gaining Ratings Points on both Systems while the 2nd-placed Collingwood kept the same Rating on MoSSBODS and fell slightly on MoSHBODS. Geelong performed similarly to Collingwood across the two Systems and remains 3rd on both.

Overall, just five teams changed ranking on MoSSBODS, none from the Top 8, and only six changed ranking on MoSHBODS. No team moved by more than two places.

Those moves left the Systems now differing in their rankings of all but the Dogs, Eagles and Dockers by no more than two places. The Dogs are 7th on MoSSBODS and 10th on MoSHBODS, the Eagles still 12th on MoSSBODS and 9th on MoSHBODS, while the Dockers are now 15th on MoSSBODS and 12th on MoSHBODS.

Eight teams - the MoSHBODS Top 8 - now have a positive Combined Rating on both Systems, while the Dogs still have a positive MoSSBODS but a negative MoSHBODS Combined Rating. The gap between 1st and 8th on MoSSBODS now stands at 5.3 Scoring Shots (up 0.6), and between 1st and 8th on MoSHBODS at 20.0 points (down 0.4).

On the component ratings, GWS remains 1st on offence and Collingwood 1st on defence on both Systems. GWS also remains 2nd on defence, and Collingwood 2nd on offence on both Systems.

On MoSSBODS, 7 teams are now rated positively on offence and defence (down 1), 3 are rated negatively on both (down 1), 3 are rated positively on offence but negatively on defence (up 2), and 5 are rated negatively on offence but positively on defence (no change).

Only one team is now in different quadrants under the two Systems:

  • Port Adelaide (positive offence and defence on MoSSBODS, negative offence but positive defence on MoSHBODS)

Looking across all 18 teams we find that:

  • on offence, only two teams are ranked more than 2 spots differently by the two Systems (Port Adelaide and Adelaide)

  • on defence, four teams are ranked more than 2 spots differently by the two Systems (Port Adelaide, Essendon, Melbourne, St Kilda, and Fremantle). There’s something of a theme emerging this year that assessing teams’ defensive abilities based solely on scoring shots conceded (MoSSBODS) is quite different in a number of cases from assessing them on both scoring shots and points conceded (MoSHBODS).

Next, let’s compare each team’s current ratings with those of teams from the past at the same point in their respective seasons (ie after ten rounds of the home-and-away season).

Teams shown as red points are teams that eventually finished premiers, and those shown in orange finished as runners up.

Collingwood and GWS remain the only teams with a Combined Rating at or above the median for all previous Grand Finalists at this point in the season, and Richmond, Geelong, and Port Adelaide the only other teams with Combined Ratings above the lowest decile for all previous Grand Finalists. Sydney, Carlton and Gold Coast all have Combined Ratings lower than that of any previous Grand Finalist at this point in the season.

If we focus purely on those seasons from 2000 on, we again obtain a similar picture (although a lot more teams find themselves with Combined Ratings under the lows for previous Grand Finalists).

The following animation shows the path that each team has followed, at the end of each round, to get to its current rating, and highlights the relatively small nature of the moves this week.

ChiPS and MARS left Geelong in 1st place this week, and MARS left Collingwood in 2nd and GWS in 3rd. ChiPS, however, switched Richmond into 2nd and relegated Collingwood into 3rd.

Across the two Systems, only ChiPS moved any team by more than 2 places, swapping North Melbourne into 12th from 15th, and the Western Bulldogs in 15th from 12th.

That’s left the two of them disagreeing about the ranking of no team by more than two places. Both now have their Top 8 teams rated as better-than-average teams (ie rated over 1,000), but MARS also has its 9th-placed team, Port Adelaide, in that same category.

Looking across the rankings of all four Systems and ordering the teams based on the current competition ladder, we find that:

  • Western Bulldogs still has the widest range of rankings (7th on MoSSBODS and 15th on ChiPS and MARS)

  • Sydney and West Coast have the next-widest range of rankings (Sydney is 9th on ChiPS and 16th on MoSSBODS and MoSHBODS; West Coast is 5th on ChiPS and MARS, and 12th on MoSSBODS)

  • Port Adelaide has the next-widest range (5th on MoSSBODS and 10th on ChiPS and MARS)

  • No other team is ranked more than four places differently across the four Systems.

  • Gold Coast and Carlton are now the only teams ranked identically by all four Systems, but seven other teams’ rankings cover only two or three values.

We now see fairly large positive differences between ladder position and Rating System rankings (ie red dots, where Rating System ranking is much lower than ladder position) for only the Lions, Dockers and Saints, and large negative differences (ie green dots) for, still, only the Dons.