Saturday, September 18, 2010

Visualising AFL Grand Final History

I'm getting in early with the Grand Final postings.

The diagram below summarises the results of all 111 Grand Finals in history, excluding the drawn Grand Finals of 1948 and 1977, and encodes information in the following ways:
  • Each circle represents a team. Teams can appear once or twice (or not at all) - as a red circle as Grand Final losers and as a green circle as Grand Final winners.
  • Circle size if proportional to frequency. So, for example, a big red circle, such as Collingwood's denotes a team that has lost a lot of Grand Finals.
  • Arrows join Grand Finalists and emanate from the winning team and terminate at the losing team. The wider the arrow, the more common the result.
No information is encoded in the fact that some lines are solid and some are dashed. I've just done that in an attempt to improve legibility. (You can get a PDF of this diagram here, which should be a little easier to read.)



I've chosen not to amalgamate the records of Fitzroy and the Lions, Sydney and South Melbourne, or Footscray and the Dogs (though this last decision, I'll admit, is harder to detect). I have though amalgamated the records of North Melbourne and the Roos since, to my mind, the difference there is one of name only.

The diagram rewards scrutiny. I'll just leave you with a few things that stood out for me:
  • Seventeen different teams have been Grand Final winners; sixteen have been Grand Final losers
  • Wins have been slightly more equitably shared around than losses: eight teams have pea-sized or larger green circles (Carlton, Collingwood, Essendon, Hawthorn, Melbourne, Richmond, Geelong and Fitzroy), six have red circles of similar magnitude (Collingwood, South Melbourne, Richmond, Carlton, Geelong and Essendon).
    I recognise that my vegetable-based metric is inherently imprecise and dependent on where you buy your produce and whether it's fresh or frozen, but I feel that my point still stands.
  • You can almost feel the pain radiating from those red circles for the Pies, Dons and Blues. Pies fans don't even have the salve of a green circle of anything approaching compensatory magnitude.
  • Many results are once-only results, with the notable exceptions being Richmond's dominance over the Blues, the Pies' over Richmond, and the Blues over the Pies (who knew - football Grand Final results are intransitive?), as well as Melbourne's over the Dons and the Pies.
As I write this, the Saints v Dogs game has yet to be played, so we don't know who'll face Collingwood in the Grand Final.

If it turns out to be a Pies v Dogs Grand Final then we'll have nothing to go on, since these two teams have not previously met in a Grand Final, not even if we allow Footscray to stand-in for the Dogs.

A Pies v Saints Grand Final is only slightly less unprecedented. They've met once before in a Grand Final when the Saints were victorious by one point in 1966.

2 comments:

Anonymous said...

Great diagram!You certainly gain a better appreciation for the Collywobbles phenomenon.

TC said...

Thanks.

Re Collingwood's sometime depressing performance in the Big One, I guess you can pick your camp:

Camp A: Better to have hoped and hurt than never to have hoped at all.

Camp B: Better not to have felt the slings and arrows of outrageous fortune.

Camp C: Better to eschew platitudinous aphorisms altogether, especially if the best you can do is to paraphrase them.

Anyway, FWIW, my statistically informed opinion is that it'll be the Pies' green bubble that'll grow on Saturday, not its red one.

TC