2023 : Simulating the Final Ladder After Round 19
/The latest simulations (and this week there are 50,000 of them, which means that the 95% confidence intervals for the probability estimates fall from 1% to 0.4%), suggest that there are now 12 teams with a 1-in-4 or better chance of playing Finals.
Those simulations suggest that the teams can now be roughly grouped as follows:
Collingwood: certain of finishing Top 4; and 85% chance of being Minor Premier
Port Adelaide and Brisbane Lions: certain of being finalists; almost certain of finishing Top 4; and 5 to 10% chance of being Minor Premier
Melbourne: almost certain of being finalists; 80% chance of finishing Top 4; but virtually no chance of being Minor Premier
Western Bulldogs and Geelong: 80 to 85% of being finalists; 8% chance of finishing Top 4; and no chance of being Minor Premier
Carlton: 60% of being finalists; 5% chance of finishing Top 4; and no chance of being Minor Premier
GWS and Richmond: about 40% chance of being finalists; about 3-in-200 chance or less of finishing Top 4; and no chance of being Minor Premier
Essendon, St Kilda, and Sydney: 25 to 30% chance of being finalists; virtually no chance of finishing Top 4; and no chance of being Minor Premier
Adelaide: about 15% chance of being finalists; virtually no chance of finishing Top 4; and no chance of being Minor Premier
Gold Coast: about 5-in-200 chance of being finalists; no chance of finishing Top 4; and no chance of being Minor Premier
Fremantle: virtually no chance of being finalists; no chance of finishing Top 4 or being Minor Premier
Hawthorn, North Melbourne, and West Coast: 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.
As the home and away season draws to a close, we again see mostly small changes in Expected Win values this week, the highest being +0.7 wins for Collingwood, and the lowest -0.7 wins for Port Adelaide.
Western Bulldogs, GWS, and Sydney enjoyed the largest percentage point increases in their estimated finals chances, and Essendon suffered the largest decline.
The range of expected wins now runs from 1.8 to 19.1 (from 1.7 to 18.4 at the end of Round 18).
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 19 saw some significant reductions in the uncertainties around the final home and away ladder, and left half of the teams currently effectively fighting for between 6 and 10 ladder positions, and half the ladder positions having 5 to 9 teams effectively fighting for them.
On the teams side, those with least uncertainty are West Coast, North Melbourne, Hawthorn, and Collingwood, 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 6th to 13th.
We also see that the average team is effectively competing for about 5.3 positions, and the average ladder position has about 5.2 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 Sydney, GWS, and Richmond, 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 many teams are still about 25% chances of playing Finals if they finish on 12 wins, although the figure is closer to 50% for Adelaide, Carlton, Geelong, Melbourne, and Sydney, We also see that all teams have about 90% or better chances of playing Finals 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 and find that 14 wins will make Brisbane Lions and Melbourne about 50:50 chances for a Top 4 spot, but will give most other teams only about 25% chances or less. Fifteen wins will make all teams about even-money chances or better to finish Top 4, but makes Brisbane Lions, Melbourne, and Port Adelaide better 85% chances. With 16 wins, the probabilities are near certainty for every team capable of registering that many.
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: 31% had 12 wins (down 6%), 20% had 13 wins (no change), and 44% had 12.5 wins (up 8%). Also, 2% had 13.5 wins (no change)
For teams finishing 4th in a replicate: 41% had 15 wins (up 4%), 23% had 16 wins (up 2%), and 2% had 15.5 wins (down 3%). Also 15% had 14 wins (down 2%), and 12% had 14.5 wins (down 2%)
For teams finishing win 11 wins: none made Finals
For teams finishing win 12 wins: 26% made Finals (down 6%)
For teams finishing win 13 wins: 96% made Finals (no change)
For teams finishing win 14 wins: almost 100% 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 is still a slightly lower than 1-in-6 chance that 4th will be decided on percentages
There’s now about a 3-in-20 chance that 1st will be decided on percentages (which is down by about 6% points)
TOP X TEAMS
Top 2
In the latest simulations there were four combinations of teams that finished 1st and 2nd at the end of the home and away season in at least 5% of replicates:
Collingwood/Port Adelaide: 41%
Collingwood/Brisbane Lions: 38%
Brisbane Lions/Collingwood: 9%
Collingwood/Melbourne: 7%
Top 4
In the latest simulations there were four combinations of teams that finished 1st through 4th at the end of the home and away season in at least 5% of replicates:
Collingwood/Port Adelaide/Brisbane Lions/Melbourne: 24%
Collingwood/Brisbane Lions/Port Adelaide/Melbourne: 20%
Collingwood/Brisbane Lions/Melbourne/Port Adelaide: 9%
Collingwood/Port Adelaide/Melbourne/Brisbane Lions: 8%
GAME IMPORTANCE
Here is an updated list of the Top 10 most important remaining games for each team. Note that teams no longer have 10 games left to play, so matches involving other teams will make it onto their list. Note also that I have ignored games with weighted importance values below 0.01.
(For details on how this metric is calculated, see this blog)
From that table we can see that the Round 20 games are likely to be of:
High Importance for: Carlton, Essendon, GWS, Richmond, and Sydney
Moderate Importance for: Adelaide, St Kilda, and Western Bulldogs
Low Importance for: Geelong and Gold Coast
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.
GRAND FINALS
In the latest simulations there were seven pairs of teams that met in the Grand Final in at least 5% of replicates:
Collingwood/Brisbane Lions: 12%
Collingwood/Port Adelaide: 10%
Brisbane Lions/Melbourne: 8%
Port Adelaide/Brisbane Lions: 7.5%
Collingwood/Melbourne: 6%
Port Adelaide/Melbourne: 6%
Brisbane Lions/Geelong: 6%
POINT OF ELIMINATION
Looking just at Flag projections, we have:
Collingwood at about 12-in-50
Brisbane Lions at about 9-in-50
Melbourne at about 3-in-20
Port Adelaide and Geelong at about 1-in-8
Carlton at about 1-in-14
Western Bulldogs at about 1-in-20
