2019 : Simulating the Final Ladder After Round 18
/The results of the latest 50,000 simulations appear below.
(If you’re curious about the methodology used to create them, you can start here.)
RESULTS
Eight teams now have strong claims to a spot in the Finals (70% or better) with only two more, Port Adelaide and Hawthorn, having estimated double-digit chances. The race for the Top 4 is a little less settled, with six teams having a 40% or better shot and one more, Essendon, an estimated 14% chance.
Geelong’s loss and Brisbane Lions’ win meant that the Cats’ grip on the Minor Premiership loosened. It is now only a 62% chance for the Minor Premiership, with the Brisbane Lions’ chances rising to 22%.
The biggest losers in terms of Expected Wins this week were the Western Bulldogs (down 0.8 wins), and the biggest gainers were Essendon (up 0.8 wins).
In terms of estimated probability of making the Finals, the largest moves were:
BIGGEST LOSERS
Western Bulldogs (down 16% points)
Port Adelaide (down 14% points, making it 44% points in two weeks)
Adelaide (down 10% points)
BIGGEST GAINERS
Essendon (up 21% points, making it 40% points in two weeks)
GWS (up 9% points)
Collingwood this week saw a 25% point decrease in its Top 4 prospects, and Adelaide a 13% point decrease, while GWS saw a 13% point increase, and West Coast a 10% point increase.
DETAILED LADDER FINISH ESTIMATES
The detailed view of each team’s estimated probability of finishing in each of the 18 possible ladder positions appears below. Blank cells represent ladder finishes that did not occur even once in the 50,000 simulations, while cells showing a value of 0 represent estimated probabilities below 0.05%.
Considering how late we are in the home-away season, the amount of uncertainty that remains about which teams will finish where seems quite high - a reflection of the relatively even nature of the competition this year. Most teams still have at least 4 or 5 positions which they are estimated as having at least 10% chances to fill.
WINS REQUIRED FOR TOP 8 AND TOP 4
GWS still have the best prospects of a Top 8 berth should they finish 11 and 11 for the season, but still have only about a 40% chance should they do so. Only Adelaide, amongst the remaining teams, is assessed as having better than a 1 in 4 chance of playing Finals with just 11 wins.
With 12 wins, the Giants are virtual certainties of playing Finals, and Adelaide have about a 90% chance. The estimated chances for most other teams lie broadly in the 50 to 75% range (Collingwood and Richmond a little higher), the exceptions being the Saints, who remain worse than even-money prospects even if they finish the season 5 and 0 from here.
The estimated probability of the team in 8th spot finishing with just 10 wins has risen slightly this week to 0.3%, or about 1 in 320.
Fourteen wins gives the eight teams capable of registering that many a very wide range of estimated chances of finishing Top 4. GWS’ and Geelong’s chances are roughly 70 to 80%, while Essendon’s, Richmond’s, and West Coast’s are roughly 30 to 40%.
With fifteen wins, all seven teams capable of achieving that tally are at least 90% chances of finishing Top 4.
The most-likely tally of wins for teams in various final home-and-away ladder positions are:
1st: 16 wins
2nd and 3rd: 15 wins
4th and 5th: 14 wins
6th and 7th: 13 wins
8th: 12 wins
9th and 10th: 11 wins
11th and 12th: 10 wins
13th and 14th: 9 wins
15th: 8 wins
16th: 7 wins
17th: 6 wins
18th: 3 or 4 wins
TOP 2s AND TOP 4s
This week, again, we’ll look at what the simulations are suggesting are the most-likely combinations of teams finishing in key positions.
For Top 2s, we have the situation as shown at right, which still sees a Geelong-Brisbane Lions 1-2 finish as, fairly comfortably, the most likely, it occurring in about 1 simulation in 4. Geelong-West Coast, and Brisbane-Geelong finishes are the next most-likely, each occurring in about 1-in-8 to 1-in-10 simulations.
No other pairing has an estimated probability above 10%.
Across all 10 of the combinations shown here, six different teams appear at least once: Geelong, Brisbane Lions, West Coast, Richmond, Collingwood, and GWS. Combined, the 10 combinations represent 88% of all of the simulations.
Looking next at Top 4s, we see that even the most-likely combination appears in only 3% of simulations, that being for a Geelong-Brisbane Lions-West Coast-GWS finish.
Six other orderings appeared in 2% or more of the simulations.
Across all 10 of the combinations shown here, six different teams appear at least once: Geelong, Brisbane Lions, West Coast, GWS, Collingwood, and Richmond. Combined, the 10 combinations represent only 23% of all of the simulations.
In terms of the Top 8, there were 19,131 different orderings this week across the 50,000 simulations, none of them occurring more than 105 times (0.21%). In other words, even the current most-likely Top 8 ordering is about a 475/1 shot.
If we ignore order, we find 174 unique combinations of teams in the Top 8s across the simulations, the most commonly occurring set of being the eight teams currently filling the Top 8 spots on the ladder, namely Adelaide, Brisbane Lions, Collingwood, Essendon, Geelong, GWS, Richmond, and West Coast, which turned up in just over 1 simulation in 2.
LIKELIHOOD OF PERCENTAGE DETERMINING POSITIONS
Next we’ll analyse how likely it is that key positions on the final home-and-away ladder will be determined by percentage because the teams in those positions finish tied on competition points.
This week, 4th and 5th are separated by percentage in about 51% of the simulations (up 4% points), and 8th and 9th are separated by percentage in about 42% of the simulations (down 4% points). As well, 8th and 10th are separated by percentage in about 16% of the simulations, and 8th from 11th in about 5%.
As well, in about 1 simulation in 3, 1st and 2nd are separated only by percentage.
TEAM AND POSITION CONCENTRATION
One way of measuring how much uncertainty there is in the competition is to use the Gini measure of concentration commonly used in economics for measuring income inequality to quantify the spread of each team's estimated final ladder positions across the 50,000 simulation replicates, and to quantify the concentration in the probabilities across all the teams vying for any given ladder position.
This week saw the uncertainty about the final ordering of the teams decrease quite significantly again, with the Gini coefficients rising to around 0.71.
At the team level, we saw reductions in uncertainty for 15 teams, the biggest being for Adelaide and Essendon. The biggest increases in uncertainty came for St Kilda, Collingwood, and Geelong.
Fremantle, North Melbourne, Western Bulldogs, Port Adelaide, Richmond and Collingwood now have the most uncertainty, while Gold Coast, Geelong, Carlton and Melbourne have the most certainty about their eventual ladder finishes.
If we adopt a ladder position viewpoint instead, we see that 1st and 18th remain the positions with the narrowest range of likely occupants, albeit that the uncertainty associated with 1st position increased this week (as it did for 3rd place, as well).
The biggest increases in certainty came for positions 5th through 11th (especially, 7th through 10th). Notwithstanding those increases, the positions with most uncertainty are 8th through 14th.
Roughly speaking, we have now about the same level of uncertainty associated with the final ladder as we did at the end of Round 17 last year, although a lot more certainty about positions 1st to 8th than we did then.
GAME IMPORTANCE
Here are the updated assessments of the 30 most-important games between now and the end of the home-and-away season. (See this blog for details about how these are calculated.)
Adelaide is now involved in four of the top 5, and five of the top 8 games in terms of estimated likely impact on the Final 8. Port Adelaide is involved in two of the top 6.
To finish we’ll again look at the importance of the remaining games in terms of their estimated likely impact on the Top 4 (using an equivalent methodology to that we used for assessing the likely impact on the Top 8).
Here, we find Richmond are involved in three of the five highest impact games, and Collingwood in four of the seven highest, with both playing one another this coming weekend.
