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2023 : Simulating the Final Ladder After Round 12

Tony Corke

There are now 10 teams with about a 2-in-5 or better chances of playing Finals (and another two teams with around 1-in-3 chances), eight teams with about a 1-in-9 or better chance of finishing Top 4, and three teams with about a 1-in-5 or better chance of finishing as Minor Premiers.

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

  1. Collingwood: almost certain of being a finalist; 90% chance of finishing Top 4; and 50% chance of being Minor Premier

  2. Port Adelaide and Brisbane Lions: better than 95% chance of being finalists; 75% chances of finishing Top 4; and 20% chance of being Minor Premier

  3. Melbourne: 90% chance of being finalists; 60% chance of finishing Top 4; and about 9% chance of being Minor Premier

  4. Western Bulldogs: 75% chance of being finalists; 30% chance of finishing Top 4; and about 1 to 2% chance of being Minor Premier

  5. St Kilda, Essendon, and Geelong: about 50 to 60% chance of being finalists; about 10 to 15% chance of finishing Top 4; and 0.5% chance of being Minor Premier

  6. Fremantle and Adelaide: about 40 to 45% chance of being finalists; about 6 to 9% chance of finishing Top 4; and 0.1 to 0.5% chance of being Minor Premier

  7. Gold Coast and Sydney: about 30% chance of being a finalist; 4 to 5% chance of finishing Top 4; and virtually no chance of being Minor Premier

  8. Carlton and Richmond: roughly 10% to 20% chance of being finalists; 1% chance of finishing Top 4; and little to virtually no chance of being Minor Premier

  9. GWS: about 3% chance of being a finalist and virtually no chance of finishing Top 4 or being Minor Premier

  10. Hawthorn, North Melbourne, and West Coast: little to no chance of being finalists, finishing Top 4. or 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 see only very small changes in Expected Win values this week, the highest being +0.9 wins for Gold Coast, and the lowest -0.8 wins for Adelaide.

Gold Coast enjoyed the largest percentage point increases in their estimated finals chances, and Adelaide suffered the largest decline.

The range of expected wins now runs from 2.5 to 17.8 (from 2.5 to 17.7 at the end of Round 11).

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

Round 12 results left us with about the same level of uncertainty that we had at the end of Round 10, with that around teams falling by about 0.3 positions per team and that around ladder positions falling by about 0.3 teams per position. Half of the teams are now currently effectively fighting for between 10 and 12 ladder positions, and half the ladder positions have 10 to 12 teams effectively fighting for them.

On the teams side, those with least uncertainty remain West Coast, North Melbourne, Collingwood, and Hawthorn and, on the ladder positions side, those with least uncertainty are still 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 5th to 12th.

We also see that the average team is effectively competing for about 8.1 positions, and the average ladder position has about 8.1 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 West Coast, Hawthorn, North Melbourne, and Collingwood). Contrast the results for those teams with, say, those for St Kilda, Fremantle, Geelong and Sydney, which are the teams with the most uncertainty according to the HHI.

In the next chart we look at the probability that each team plays Finals given that it finishes with a specified number of wins.

We see that most teams are only about 25% chances of playing Finals if they finish on 12 wins, but mostly better than 75% chances if they finish on 13 wins.

Next, let’s look at what’s required for a Top 4 finish.

Here we see more variability across the teams but find that 15 wins will make most teams about even-money chances or better to finish Top 4. With 16 wins, the probabilities are all over 75%.

Next, we show the relationships between ladder position and wins after aggregating across teams.

Based on the simulations, we can say that:

  • For teams finishing 8th in a replicate: 27% had 12 wins (up 1%), 45% had 13 wins (no change), and 11% had 12.5 wins (no change). Also, 8% had 14 wins (down 1%), and 5% had 13.5 wins (down 1%)

  • For teams finishing 4th in a replicate: 43% had 15 wins (up 1%), 27% had 16 wins (no change), and 5% had 15.5 wins (down 1%). Also 14% had 14 wins (up 1%), and 4% had 14.5 wins (down 1%)

  • For teams finishing win 11 wins: 1% made Finals (no change)

  • For teams finishing win 12 wins: 25% made Finals (up 1%)

  • For teams finishing win 13 wins: 80% made Finals (up 1%)

  • For teams finishing win 14 wins: 99% made Finals (no change)

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 is still about a 2-in-5 chance that 8th will be decided on percentages

  • There remains a slightly higher than 35% chance that 4th will be decided on percentages (which is up a couple of percentgae points)

  • There’s still about a 1-in-5 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 still have Collingwood now as solid favourites for the Flag at just under 1-in-4 chances, ahead of Melbourne (1-in-6), Brisbane Lions (3-in-20), Port Adelaide (1-in-8), Geelong (1-in-11), and Western Bulldogs (1-in-16).