Winners v Losers – Some Analysis

While looking over the Superladder in yesterday’s Herald Sun (best part of their footy coverage), I looked at next week’s fixture to find who the Bulldogs would play.

I found we would play St Kilda at Etihad, and, using the small sample sizes known to mankind since time immemorial, thought, “Since they lost in round 1, and we won, we should win.” I then noticed that several other winning teams would play teams that had lost the previous week.

A quick check found that, if Geelong beat Hawthorn that day, then every team that won in round 1 would play a team that had lost.

I mulled over that thought while getting fish and chips for dinner. The odds of that, I thought to myself, are something like 512 to 1. That’s kind of unlikely, but not really.

But, with a burst of enthusiasm, what if every team that won in round 1 won again? The odds of that are…around 250,000 to 1. (I could have gotten a more precise figure if I’d tried, but it was Easter. I’d eaten a lot of chocolate.)

And even then, using the sort of mathematics that only someone who is used to probability would consider, they’re the odds of it happening at any time. What are the odds of it happening in the first two rounds? 5 million-ish to 1. (Again, chocolate).

With that, the fish and chips came, so I went home, ate them, and then watched TV.

This morning, at 11 o’clock, I tweeted about it:

And then, I went into a frenzy of checking AFL Tables (the greatest AFL stats website of all time) to see if anything like that had ever happened.

An honourable mention goes to 1914, where five teams had no losses and five teams had no wins after two rounds. However, Essendon and Collingwood had had a draw in round 1, before winning in round 2. Geelong and Carlton had also had a round 1 draw, but lost in round 2. Regardless, that’s the only time there had been half undefeated and half winless.

Anyway, after 45 minutes of searching through AFL Tables, I found the answer. Had their ever been an AFL season where, after two rounds, half the teams were 2-0 and half the teams were 0-2?

No.

The closest I got was in 1995, where seven of the sixteen teams were 2-0, and vice versa. The exceptions were Hawthorn and the Brisbane Bears, who were 1-1.

Anyway, here’s some more interesting stuff:

Lucas Garth helped me out, telling me about the 2003 season. However, all but three of the teams that had won lost the next week, putting this way off.

On the issue of the probabilities, I’ll let Tony Corke (of the brilliant Matter of Stats) speak:

However, it turns out…

And now, on the flipside of things: Has there ever been a round where, after two weeks, every single team is 1-1? If not, what’s the closest?

The answer is no. The closest is in 1911 and 1913, when just 1 team out of 10 was undefeated.

And just for your enjoyment, I spent ages making a chart of this all:

undefeated teams(The definition of undefeated, for the purposes of this chart, is to have won every game. And also, the missing years are the ones with an odd number of teams).

If you want, download the spreadsheet here, and have a play around. Tell me what you find.

Good luck to all the teams this week, especially the ones that could break the records.

Advertisements

One comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s