Matter of Stats

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2023 : Simulating the Final Ladder After Round 5

There are now nine teams with 60% or better chances of playing Finals, better than 25% chances of finishing Top 4, and about 5% or better chances of finishing as Minor Premiers.

Those simulations suggest that the teams can now be roughly grouped as follows:

  1. Collingwood: roughly 90% chance of being a finalist; 70% chance of finishing Top 4; and 30% chance of being Minor Premier

  2. St Kilda, Sydney, Melbourne, and Brisbane Lions: roughly 75 to 80% chance of being a finalist; 40 to 45% chance of finishing Top 4; and 9 to 12% chance of being Minor Premier

  3. Geelong, Port Adelaide, Essendon, and Adelaide: roughly 60 to 70% chance of being a finalist; 25 to 35% chance of finishing Top 4; and 5 to 6% chance of being Minor Premier

  4. Carlton: 50% chance of being a finalist; 20% chance of finishing Top 4; and 4% chance of being Minor Premier

  5. Western Bulldogs: 35% chance of being a finalist; 9% chance of finishing Top 4; and 1% chance of being Minor Premier

  6. Richmond and Fremantle: 20 to 25% chance of being a finalist; 5 to 6% chance of finishing Top 4; and little chance of being Minor Premier

  7. Gold Coast and GWS: roughly 7 to 10% chance of being a finalist; 1 to 1.5% chance of finishing Top 4; and little to virtually no chance of being Minor Premier

  8. North Melbourne, West Coast, and Hawthorn: 1% chance of being a finalist; little chance of finishing Top 4; and virtually no chance of being Minor Premier

(For anyone who is curious about the precise methodology used for these simulations, please refer to this blog post over on the General Probability and Statistics journal)

LADDER FINISHES

The ladder projections using the Heretical outputs appear below.

We again see some quite large changes in Expected Win values for some teams - as much as +1.3 or higher for Essendon, Brisbane Lions, and Adelaide, and -1.3 or lesser for North Melbourne, Melbourne, Carlton, and Richmond.

The range of expected wins now runs from 5.8 to 16.5 (from 6.2 to 16.2 at the end of Round 4).

TEAM AND POSITION CONCENTRATION

The HHI figures for these pre-season simulation replicates appear below. These provide us with estimates of:

  • How many ladder positions a team is currently effectively fighting for

  • How many teams are currently effectively fighting for a given ladder position

HERETICAL METHODOLOGY

The new data reveals that Round 5 results again only slightly reduced the uncertainty associated with each team and ladder position. About half of the teams are currently effectively fighting for between 12.5 and 14.5 ladder positions, and about half the ladder positions have 12 to 15 teams effectively fighting for them.

On the teams side, those with least uncertainty are now Hawthorn, North Melbourne, West Coast, and Collingwood, and on the ladder positions side, those with least uncertainty are 1st, 16th, 17th, and 18th.

We see that the ladder positions with the most uncertainty remain those in the middle of the table, from about 6th to 13th.

We also see that the average team is effectively competing for 11.1 positions, and the average ladder position has about 11.1 teams competing for it.

WINS AND LADDER POSITION

The charts below investigate the relationships between ladder position and number of wins.

Firstly, we show the relationships by team, which illustrate the comments from the previous section about the teams with least uncertainty about their final home-and-away ladder finishes (viz Hawthorn, North Melbourne, West Coast, and Collingwood). Contrast the results for those teams with, say, those for Carlton and Essendon, which are the teams with the most uncertainty according to the HHI.

Next, we show the relationships after aggregating across teams.

Based on the simulations, we can say that:

  • For teams finishing 8th in a replicate: 23% had 12 wins (down 5%), 38% had 13 wins (up 4%), and 13% had 12.5 wins (down 1%)

  • For teams finishing 4th in a replicate: 36% had 15 wins (up 4%), 27% had 16 wins (up 2%), and 10% had 15.5 wins (down 2%). Also 10% had 14 wins (down 1%), and 7% had 14.5 wins (down 1%)

  • For teams finishing win 11 wins: 2% made Finals (down 2%)

  • For teams finishing win 12 wins: 27% made Finals (down 8%)

  • For teams finishing win 13 wins: 78% made Finals (down 4%)

  • For teams finishing win 14 wins: 98% made Finals (down 1)

LIKELY IMPORTANCE OF PERCENTAGE

Next, we’ll use the simulations to investigate the estimated likelihood that any given pair of ladder positions will be determined after Round 24 based on percentage.

So, our new estimates are that:

  • There’s now a slightly higher than 1-in-3 chance that 8th will be decided on percentages

  • There’s now about a 1-in-3 chance that 4th will be decided on percentages

  • There’s now about a 9-in-50 chance that 1st will be decided on percentages

FINALS CHANCES

Finally we take another look at team’s chances all the way through to the Grand Final, making reasonable assumptions about where Finals will be played given the participants and week of the Finals.

We have Collingwood still clear favourites for the Flag at around 1-in-4 chances, ahead of Geelong (1-in-8), Melbourne (1-in-9), Sydney (1-in-10), Brisbane Lions (1-in-14), and St Kilda (1-in-14).