Monday, 3 November 2014

Fixture - Correct Weight?

As is the flavour of the moment, we turn our attention to the 2015 fixture issued by the AFL, and assess 'who got the tough one'.

Its an annual thing, now in its fourth fabulous season*, and very much due for a ringing celebrity endorsement (Oh, I don't know... maybe of the Coach Ronnie value?).

*Past assessments here: 2014, 2013, 2012.

The AFL Fixture.

The fixture is in and released on 30 October, and fully available here [PDF]
For season 2015, the AFL attempted a new determination of the fixture - a selection of teams to play inside groups based on ladder positions.

The "weighted rule" will be in effect again, with each club to play every other club once and five clubs twice.
This is done in accordance with last year's ladder, with the clubs grouped into top six, middle and bottom teams to manage the equality of the double match-ups.
 "We're happy with the way it works. I think if you look at it, all the right teams are playing each other in our view," said Simon Lethlean, the AFL's general manager of broadcasting and scheduling.
McLachlan denied it was a "handicap" format.
"In an imperfect world, which our fixture is and we've acknowledged that for many years, you're playing at the margins and all we've done is actually get some slight weighting going into who plays who twice," McLachlan said.

Sort of a 'weighted rule', but really a handicap. Hell, even Stevo can see that!

Given it is a 'handicapping', at least it is not the outright gerrymandering we have seen in the past. At least now there is some semblance of structure to fixing the fixture.
One again, Stevo with the detail (IKR!!!).

Which is a really handy picture, because it lays out the structure for the fixture in a simple easy to read format.
And it also shows that the AFL have also left themselves enough wriggle room to schedule up games according to ground availability etc. Which is a handy way of saying 'we will schedule what ever we want'.

Those 'maximum' / 'minimum' quotas are there just so they AFL can still fit in a double-up on Derbies, Showdowns and Melbourne blockbusters.

Its a handy way of scheduling to look like your doing the right thing, but not really so as not to upset the status quo and those who benefit from it.

If the AFL were fair dinkum about competitive balance and equalisation, they don't need to go full-on conferences, but an even more scaled down version where each team plays others ranked similarly.

But back to 'who got dudded'.

Assessments of the Fixture:

We have run the assessment based on our numbers below, but it is worth pointing out firstly that:

Troy Wheatley has also assessed the fixture using his rankings, and has blogged them thus.
Interestingly he defines Port Adelaide with the toughest draw (followed by Geelong, Hawthorn, and (oddly) Gold Coast).
At the top of Troys table (the soft end of the draw) he calculates West Coast getting the best run of it (?!?) followed by Melbourne, the Western Bulldogs and GWS.

Now, this does not align neatly with what the AFL are trying to do so much (i.e. stronger teams get a harder draw, etc), as evidenced by the Suns bobbing up in 4th (and the Saints and Magpies in 6th and 7th).

Troy goes on in another blog post to consider our proposal (that teams should play against others ranked similarly) and determined that
"the FootyMaths proposal ...seems to me about as fair as you can get with each team playing 22 matches"
Gotta be happy about that.

As always Rohan Connolly at The Age has assessed the fixture using the (soon to be patented, no doubt) 'Connolly Method', as below.

This method, as the detail at the top points out used the AFL ladder position along with the fundamentals of the fixture (including days break, travel etc) to award points to each team, and then rank them.

Under this system, the teams 'Play Twice' numbers tally up to show that the top 8 from last year fit into
the top 10 'toughest fixture' ranking. Joining them are Adelaide (51pts, ranking in 6th) and Collingwood - equal 9th/10th with Essendon.

Once the 'Road Trips', '6 Day Breaks' and 'Home vs Interstate' mix data is added, Collingwood slip down the difficulty scale, leaving the top 8 filling the 9 slots for hardest draw. Again, Adelaide are nosing their way in.

The nett effect of the 'Connolly Method' is that pretty much is in alignment with what the AFL are after... namely that the stronger teams get a harder run, and the poorer performers have a slightly easier time of it.

There are limited anomalies in the above table... only the positioning of Adelaide (10th) in the 'toughest 8', and the West Coast (9th) making out like bandits with the 5th easiest draw.

Using the FootyMaths rankings, we have also calculated our assessment of the fixture.
The table below considers the opposition strength, home/away bias, and
- quality of the opposition,
- expectations of a 'win' for each game,
- an expected end of year rank
- an expected end of season ranking for a perfectly even draw, and the
- difference between those two ranking weights.
The table below is the results, with the top of the table teams having the harder draws.

1Port Adelaide513152345806.61
5North Melbourne61226231022004.50
10West Coast9120323028-1002.96
12Brisbane Lions15874234681000.82
14Gold Coast1298922905-200-0.83
16W Bulldogs/FFC1490922908-100-1.99
18St Kilda1870322710100-2.37

In calculating these numbers we find that (based on or ranking numbers) the AFL had gone very close to achieving its 'handicapped' fixture.
The top 8 teams of the ladder are all in relative close proximity to their 'tough draw index' position, and there is also great alignment at the bottom of the spectrum too.

Looking at the above, its possible to think Port Adelaide suffer the most (+4 from their ladder position), with Brisbane also similarly affected (+3).

A range of teams have marginally benefited (-2), and these are Fremantle, Sydney, Gold Coast and Western Bulldogs.

But all in all, it looks like the AFL have achieved their outcome, so ... well done!

Its almost as if they are using our data and methodology to work up the fixture outcome... well we can dream anyway.
If only they would try a non-handicapped approach... maybe for 2016?


  1. The difference in my rating of Gold Coast's fixture from yours and Rohan Connolly's rating is not too hard to figure out. I rate two of Gold Coast’s return opponents, Adelaide and West Coast, much more highly than where they finished on the ladder in 2014. Your system does as well, but not by as much, and I also rate a third of Gold Coast’s return opponents, GWS, more highly than your system. Most of the differences in ratings even out, but I guess here we have almost a ‘perfect storm’ of differences!

  2. My 2015 AFL predictions
    1. Port Adelaide
    2. Hawthorn
    3. Geelong
    4. North Melbourne
    5. Essendon
    6. Gold Coast
    7. Richmond
    8. Fremantle
    2015 AFL award predictions
    Brownlow Medal - Gary Ablett Jnr
    Coleman Medal - Lance Franklin (he will get 85 or 90)
    Leigh Matthews Trophy - Jack Riewoldt
    Retirements Jimmy Bartel, Boomer Harvey, Dustin Fletcher, Matthew Pavlich, Nick Riewoldt,
    AFL premiers Hawthorn
    Sackings Nathan Buckley
    Mick Malthouse