Sunday, October 30, 2011

Who Has The Easiest AFL Draw in 2012?

With the release of the Australian Football League draw for 2012, analysts were quick to rate the difficulty of each team's fixture. Some went so far to come up with a numerical rating of this difficulty, generally based on who each team plays twice, road trips, and matches played against teams from interstate (see example here).

Using the AFL post-final power rankings posted on this blog a few weeks back, I have come up with the following ratings of the difficulty of each team's draw in 2012. Each team's rating is a sum over all matches of the reverse of the ranking points of their opponents (which themselves are based on those opponents' expected winning margins), adjusted for any home ground advantage. These adjustments for home ground advantage were explained here.

For now, I've assumed that Greater Western Sydney's ranking points are -50, and have treated their adjustments for travel in the same way as other non-Victorian teams (that is, +12 points for playing at home, -12 points for playing away) rather than Sydney (who have a smaller adjustment when playing Melbourne teams). I might change this before the season starts. Note also that I treat Hawthorn games in Tasmania as if they were playing in Melbourne (i.e. an advantage against non-Victorian teams, but not Victorian teams).

As an example, if Team X is playing West Coast in Perth then I deducted them -33.3 points: -21.3 due to West Coast having a ranking of +21.3, and -12 due to playing in Perth.

One main difference between my calculations and those of other analysts is that the latter do not account for the fact that higher-ranked teams do not have to play themselves. For example, Geelong gets a big boost in the ease of their fixture just by virtue of the fact that they don't have to play Geelong and other teams do.

Here are the rankings for the difficulty of each team's draw in 2012 - a higher ranking means that your draw is easier. Most team's rankings for difficulty of draw are positive since ranking points for AFL teams are skewed to the negative side, particularly with the introduction of Greater Western Sydney.

Adelaide 169.3
North Melbourne 164.4
Gold Coast 152.9
Fremantle 149.2
Melbourne 144.9
Richmond 115.1
St. Kilda 114.2
Geelong 100.7
Hawthorn 93.7
Brisbane 93.1
Greater Western Sydney 92.7
West Coast 86.6
Carlton 79.7
Port Adelaide 65.5
Essendon 46.9
Sydney 46.8
Western Bulldogs 4.5
Collingwood -9.0

So according to this system Adelaide has the easiest draw, and Collingwood has the hardest, which has pretty much been the consensus among commentators. However, Greater Western Sydney's draw is not as easy as some people think, partly because they don't get to play themselves, and partly becuase they don't have many home games at their own stadium. On the other hand, Geelong and Hawthorn have easier draws than most people think, partly because they don't have to play themselves, and in Hawthorn's case because they only travel three times to "hostile" territory.

But does it make a lot of difference? Essentially, Adelaide's draw advantages them by 178 points compared to Collingwood, so Collingwood needs to be a 178-point better team than the Crows to be expected to perform as well as them. Over the course of a season, that's about eight points per week. It's not negligible, but really if your team finds itself in 14th spot you shouldn't be blaming the fixture.

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