2023 : Simulating the Final Ladder After Round 20
/The latest simulations suggest that there are still 12 teams with a 1-in-4 or better chance of playing Finals, with eight teams that are most likely to compete for four of the eight spots.
Those simulations suggest that the teams can now be roughly grouped as follows:
Collingwood: certain of finishing Top 4; and about 95% chance of being Minor Premier
Port Adelaide, Brisbane Lions, and Melbourne: certain of being finalists; almost certain of finishing Top 4; and about 2 to 4% chance of being Minor Premier
Carlton, GWS, and Western Bulldogs: 60 to 75% of being finalists; 2 to 7% chance of finishing Top 4; and no chance of being Minor Premier
Geelong: 50% of being finalists; virtually no chance of finishing Top 4; and no chance of being Minor Premier
St Kilda, Sydney, Richmond, and Adelaide: 25 to 40% of being finalists; virtually no chance of finishing Top 4; and no chance of being Minor Premier
Essendon and Gold Coast: 5 to 10% chance of being finalists; no chance of finishing Top 4; and no chance of being Minor Premier
Fremantle: almost no chance of being finalists; no chance of finishing Top 4; and no chance of 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.
We again see mostly small changes in Expected Win values this week, the highest being +1.2 wins for Fremantle, and the lowest -1.1 wins for Geelong.
Carlton, GWS, St Kilda, and Adelaide enjoyed the largest percentage point increases in their estimated finals chances, and Western Bulldogs, Geelong, Richmond, and Essendon suffered the largest decline. Geelong’s near 32% point decline is the largest I can recall seeing for a single round.
The range of expected wins now runs from 2.3 to 18.7 (from 1.8 to 19.1 at the end of Round 19).
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
Unusually, Round 20 saw an overall increase in the uncertainties around the final home and away ladder, and left half of the teams currently effectively fighting for between about 7 and 10 ladder positions, and half the ladder positions having 6.5 to 10 teams effectively fighting for them.
Geelong, in particular, suffered an especially large increase in uncertainty, and those for Western Bulldogs and Gold Coast were also large for this time of the season.
On the teams side, those with least uncertainty are still 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 5.7 positions, and the average ladder position has about 5.7 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, St Kilda, and Geelong, 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, and Geelong, We also see that all teams have about 95% 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 75% chances for a Top 4 spot, but will give most other teams only about 30% chances or less. Fifteen wins will make GWS and St Kilda about 60% chances to finish Top 4, but makes Brisbane Lions, Melbourne, and Port Adelaide better than about 90% chances. With 16 wins, the probabilities are 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: 34% had 12 wins (up 3%), 18% had 13 wins (down 2%), and 46% had 12.5 wins (up 2%).
For teams finishing 4th in a replicate: 49% had 15 wins (up 8%), 21% had 16 wins (down 2%), and 2% had 15.5 wins (no change). Also 19% had 14 wins (up 4%), and 7% had 14.5 wins (down 5%)
For teams finishing win 11 wins: none made Finals
For teams finishing win 12 wins: 21% made Finals (down 5%)
For teams finishing win 13 wins: 98% made Finals (up 2%)
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 now about a 45% chance that 8th will be decided on percentages (which is up over 5% points)
There is now only about a 1-in-8 chance that 4th will be decided on percentages (which is down by a few percentage points)
There’s now about a 1-in-11 chance that 1st will be decided on percentages (which is down by about 4% points)
TOP X TEAMS
Top 2
In the latest simulations there were only three 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: 37%
Collingwood / Melbourne: 29%
Collingwood / Brisbane Lions: 28%
Top 4
In the latest simulations there were five combinations of teams that finished 1st through 4th at the end of the home and away season in at least 5% of replicates. Each of them occurred almost equally often:
Collingwood / Port Adelaide / Brisbane Lions / Melbourne: 16%
Collingwood / Port Adelaide / Melbourne / Brisbane Lions: 15%
Collingwood / Melbourne / Port Adelaide / Brisbane Lions: 13%
Collingwood / Brisbane Lions / Melbourne / Port Adelaide: 12%
Collingwood / Melbourne / Brisbane Lions / Port Adelaide: 12%
Collingwood / Brisbane Lions / Port Adelaide / Melbourne: 11%
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 21 games are likely to be of:
High Importance for: Adelaide, Carlton, GWS, Geelong, Richmond, St Kilda, Sydney, and Western Bulldogs
Moderate Importance for: Gold Coast
Low Importance for: Essendon
Overall, that makes it a highly important round for shaping the Final 8.
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 six pairs of teams that met in the Grand Final in at least 5% of replicates:
Collingwood / Melbourne: 11%
Collingwood / Brisbane Lions: 11%
Collingwood / Port Adelaide: 9%
Brisbane Lions / Melbourne: 8%
Port Adelaide / Melbourne: 6%
Port Adelaide / Brisbane Lions: 5%
POINT OF ELIMINATION
Looking just at Flag projections, we have:
Collingwood at about 27%
Melbourne at about 20%
Brisbane Lions at about 14%
Port Adelaide and Carlton at about 9%
Geelong at about 7%
Western Bulldogs at about 4%
Sydney at about 2.5%
