Matter of Stats

View Original

2024 - Team Ratings After Round 8

Only two teams retained their positions on MoSSBODS this week, including the Roos in last, while on MoSHBODS things were much quieter with only nine teams moving. Ratings compression had quite a lot to do with the level of change.

The multi-spot movers on both were Sydney (up 4 on MoSSBODS and 2 on MoSHBODS), Carlton (down 2 on both), and GWS (down 4 on MoSSBODS and 2 on MoSHBODS).

At the end of it all, MoSSBODS’ Top 3 is Sydney, Collingwood, and Carlton, and MoSHBODS’ is Geelong, Sydney, and Melbourne.

On both Systems, the Ratings remain compressed at the top. On MoSSBODS, 1st and 11th are separated by only 4.2 Scoring Shots (which is about 15 points), and on MoSHBODS, 1st and 10th are separated by only just over 12 points.

Still, the correlation between MoSSBODS and MoSHBODS Combined Ratings stands at +0.9892 and, roughly speaking, each team’s Combined MoSHBODS Rating is about 3.46 times its Combined MoSSBODS Rating.

On the Component Ratings, on offence we find MoSSBODS now with a Top 3 of Swans, Blues and Giants, and MoSHBODS with the same teams in a different order of Giants, Swans, and Blues. On defence both Systems still have a Top 3 of Dees, Lions, and Dockers.

MoSSBODS and MoSHBODS both now have 9 teams rated as above average on offence. MoSSBODS also has 14 teams rated as above average on defence while MoSHBODS has only 10.

We can also review the trajectory that each team has followed to arrive at its current MoSSBODS Rating.

We can put these Ratings into an historical context by seeing how they compare to the Ratings of teams from previous seasons at the end of Round 8.

There remains no standout teams so far this season with only Sydney in even the top half of teams that went on to play in the Grand Final.

On MoSSBODS, 9 teams are rated positively on offence and defence (up 3), 4 are rated negatively on both (down 2), none is rated positively on offence but negatively on defence (down 1), and 5 are rated negatively on offence but positively on defence (no change).

The correlation between the teams’ MoSSBODS offensive and defensive Ratings now stands at +0.55, which is higher than last week.

And, finally, to MARS, which re-ranked only 6 teams this week, leaving Melbourne in 3rd, but switching Sydney into 1st and pushing Geelong into 2nd.

The only teams that moved by more a single spot were Port Adelaide, down 2 into 8th, Western Bulldogs, down 2 into 10th, and Brisbane Lions, up 3 into 6th.

As we’ve seen for a while now, there is considerable Rating compression on MARS too, and now we have under 16 Rating Points separating 1st from 9th. Previous analyses have suggested that a MARS Rating Point is equivalent to roughly 0.7 points, so this gap equates to about 11 points.

Speaking of previous estimates of the value of a MARS Rating point, the Simple MARS model that forecasts margins based on 0.7 times the difference in MARS Ratings plus 11 points if the home team is facing an interstate rival, currently has a very creditable 24.45 MAE for the season.

There are now 11 teams rated better-than-average by MARS, with St Kilda rated just below 1,000.

Looking across the rankings of all three Systems and comparing them with the teams’ competition ladder positions, we find relatively large differences between the teams’ ladder positions and their rating system ordering for:

HIGHER ON LADDER THAN ON RANKING SYSTEMS: Essendon

LOWER ON LADDER THAN ON RANKING SYSTEMS: Brisbane Lions

MoSSBODS this week provides the most outlying rankings at 10, ahead of MARSwith 7, and MoSHBODS with just 4.

MARS is particularly different in terms of its ranking of Adelaide.

MoSHBODS and MARS agree about the ranking of 8 teams now, MoSSBODS and MARS about 6, and MoSSBODS and MoSHBODS about only 5 teams.

Looking finally at the range of rankings that the three Systems have attached to each team we find that Collingwood (5 spots) has the widest range of rankings, and that there are now only five teams altogether for whom the rankings span a range of more than two spots.

There are also four teams that the Systems unanimously rank: Fremantle, North Melbourne, Port Adelaide, and Western Bulldogs.