Thursday, October 30, 2014

Who Has The Easiest AFL Draw in 2015?

The 2015 AFL fixture was released today, which means it is time to do my annual assessment of the difficulty of each team’s draw. This is done by summing up, over every game a club plays, the easiness of their opponent as based on my AFL Power Rankings at the end of this season, while adjusting for home ground advantage.

The rating for each team’s draw can be broken down into three components:

-          The effect of not playing your own team: For example, Hawthorn’s draw is made easier by the simple fact that they don’t have to play Hawthorn.
 
-          Net home ground advantage: This is simply the net effect of the adjustments for home ground advantage across the season. If you want to do well on this component don’t play your ‘home’ games interstate! Geelong is rated highly because I give it home ground advantage when playing Melbourne teams in Geelong.
 
-          The effect of which teams your team plays twice: This is the collective strength of the opponents that each teams plays twice, with a higher rating for this component meaning that you have easier opponents in your return bouts.

Which clubs should send the AFL a fruit basket? The easiness of each AFL team’s draw in 2015, ranked from easiest to hardest, is shown in the table below:


Overall
Effect of not playing own team
Net home ground advantage
Effect of teams played twice
West Coast
66.5
13.4
12.0
41.2
Melbourne
57.7
-27.9
6.0
79.6
Western Bulldogs
53.4
-20.8
18.0
56.2
GWS
30.4
-21.0
0.0
51.4
Carlton
16.5
-4.6
6.0
15.1
Adelaide
9.3
16.7
0.0
-7.4
Fremantle
-7.0
15.6
0.0
-22.6
Richmond
-10.9
6.5
-6.0
-11.4
Brisbane
-11.0
-22.4
0.0
11.5
Essendon
-11.0
3.9
-18.0
3.1
Sydney
-14.2
33.8
-18.0
-30.0
Collingwood
-15.6
-12.7
-18.0
15.1
St. Kilda
-18.2
-40.7
-30.0
52.5
North Melbourne
-19.4
9.2
-18.0
-10.6
Gold Coast
-20.5
-12.0
12.0
-20.4
Hawthorn
-27.1
34.6
0.0
-61.6
Geelong
-32.6
7.1
42.0
-81.7
Port Adelaide
-46.5
21.5
12.0
-79.9


Four teams in particular should be happy with their fixtures: West Coast, Melbourne, the Western Bulldogs, and Greater Western Sydney. The AFL has tended in recent years to give teams that finish near the bottom of the ladder an easy run. This season’s last-placed team, St. Kilda, does well in terms of which teams they play twice, but has been savaged in terms of home ground advantage.
At the other end, top-ranking teams Hawthorn, Geelong and Port Adelaide have relatively tough fixtures in terms of which clubs they play twice. The difficulties of Hawthorn’s and Port Adelaide’s draws are tempered by them not having to play themselves, while Geelong as mentioned above do well out of home ground advantage.
One unusual feature of the 2015 draw ratings is that only six teams have a ‘positive’ balance while two-thirds of the competition has a ‘negative’ balance. The ratings are fixed so that they sum to zero, so it suggests that the majority ‘suffer’ in return for a few teams having really good fixtures.
On that point, I would like to compare the ‘fairness’ of the 2015 fixture with the ‘fair fixture’ proposal over at the FootyMaths Institute. I might look at that topic in a future post.

2 comments:

Rourke said...

Hi Troy,

Enjoying your blog. Nice work getting this analysis out so quickly! Have to agree with the general thrust, and Port having the toughest draw, but I can't agree with the "effect of not playing own team" which you've added to take into account the 17 rounds of all-play-all. In fact I'd argue there should be a small adjustment in the other direction, because part of an opponent's rating is due to them having played you. If you rated a full round robin using your method, you would find the top teams seem to have the easiest draws. Some more discussion here: http://www.bigfooty.com/forum/threads/luck-of-the-draw-the-age.965975/

Troy Wheatley said...

Yes, indeed I did just find that as you will see in my follow up post for today! (I did the calculations before I saw the comment.) I'd probably still argue that the top teams have the 'easiest' draws, but I can see the argument for removing this effect in terms of calculating the difficulty - indeed, part of my reason for separating out this component is so readers can do just that. Thanks for the comments!