Wednesday, 9 May 2012

SIREN! ...Quarter Time Review

The AFL season has now completed 6 rounds of a 23 round season, so we are basically at the Quarter Time break of the season.
So it is an appropriate time to check now how your team is performing this season according to our ranking data.

Last week, we published this detail about how teams are losing or gaining ranking points (I have updated the charts and table on this at the foot of this post).
But instead of using that data, another metric will be used (the rating of each team per game)
This will form the basis of the 'current form' of each team over the period of round 1 to round 6.

First, we accumulate and average the game ranking data to produce the table below. The key prima facie numbers from that table are listed under "R1-R6 FORM". This average is the current 6 game ranking performance, and effectively an indicator of form.

Remember of course that these numbers are also linked to the quality of the opposition played to date!

From these calculations, our data lists Hawthorn as the best team so far in 2012, with West Coast, Carlton and Geelong close behind in the +1200pt bracket.

Next are Collingwood, St. Kilda,  and Sydney, all in the 1200-1100pt bracket.

And at the foot of the table are Port Adelaide (800-700pt bracket), Melbourne (700-600pt bracket), Gold Coast (600-500pt bracket) and the GWS (under 500pt bracket).

So that is an indication of how your team is playing NOW relative to others, but we have taken it further by comparing it to how your team is playing now relative to its current ranking.

To do this, we benchmark the average game ranking number generated above (R1-6 form), against the ranking number the team has now (R1-6 rank) based on the cumulative data calculated over the seasons.
This then can give an indication if the team is playing above or below their current ranking, and you could suggest if there is improvement or not.

The table has this expressed in two ways, one as a points difference (Δpts), and also as a percentage difference (%Δpts). These are charted as below.

Looking at the raw points variance data, we can see that the 6 teams that have played out the first quarter of the season above their ranking (and therefore improving the most) are North Melbourne, West Coast, Port Adelaide, Richmond, Fremantle and Essendon.
These 5 teams are all playing (minimum) 50pts above their current ranking, or anywhere from 8% better than the current longer term ranking.

The counter-point to that is that Geelong and Collingwood are playing well below potential (at least 11% worse than current ranking). Geelong have played the first quarter as an 1220pt team, but still holding a 1355pt rank, and likewise Collingwood are playing to a 1170pt level while having a 1318pt ranking.

Which of course means that those teams will both be expected to drop further as the season progresses, unless they start to turn on the powerhouse performances they have shown over the last few seasons.
...and probably Geelong more-so than Collingwood, who have already lost a lot of points so far.

The other 3 teams under-performing noticeably are Melbourne, GWS, Gold Coast and the Western Bulldogs, all 8-12% under their current ranking.

Another interesting point is that Hawthorn are the top ranked team for the 6 rounds played, and only have a slight variance to their overall ranking points. This might indicate they are playing to form, and performing as expected. A 'happy team' indeed at the minute.

As mentioned before, here are the basic changes in ranking points from season start to end of the first quarter (these are revised numbers from last weeks comparison)

1 comment:

  1. TKYC, thanks for putting this up. The difficulty interpreting it is that if a team has an unknown rating, then they corrupt all the other ratings in the process.

    To explain, suppose a 1300 and a 1200 rated team play each other. Assuming their ratings are correct, you'd expect the teams to play at an average level of 1250. If the lower rated team wins by 10 points therefore, then it records a game rating of 1300, and the other 1200. And the overall rating will adjust.

    If the higher ranked team is really an 1100 rated team though, then the game merely matched expectations. (1200 and 1100 averaging 1150).

    What the rating moves and game rating table suggests therefore, is that Geelong and Collingwood are very over-rated, (maybe even borderline top-8 teams if you adjust for their own ratings). Essendon and Adelaide (particularly) have benefited from an easier draw early-on, and Hawthorn, St Kilda and North Melbourne (who should beat the Bulldogs this week) have been playing fairly well, despite results.

    Mostly though, this year seems much closer than recent past, with any of maybe 10 teams contending. Unless West Coast run away with it, which they might.