Matter of Stats

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2021 : Simulating the Final Ladder After Round 17

We’re back to a slightly more normal week this week, with all of the venues for the upcoming round already locked in, so we can feel a little more confident about the ladder simulations as they stand.

And what we find in those simulations is that, using the Standard Methodology, we still have nine teams that have a better than 1-in-3 shot at playing Finals, and seven that have about a 1-in-2 or better shot. There are also five teams that have roughly a 1-in-3 shot or better at the Top 4.

Under the Heretical Methodology, there are also nine teams that have a better than 1-in-3 shot at playing Finals, and only seven that have about a 1-in-2 or better shot. There are only four teams, however, that have a better than 1-in-3 shot or better at the Top 4.

(For details about the methodologies I’ve used, see this earlier blog. Note that I have assumed no change in fixturing for the remainder of the season except for switching the future Swans v Saints game to be a home game for the Saints)

LADDER FINISHES

Team Expected Wins under the Standard Methodology grew by 1 whole win this week for Sydney and St Kilda, and fell by 0.9 wins for Brisbane Lions and West Coast.

There were some very significant moves in terms of Finals chances, with St Kilda’s rising by 26% points to 41%, Fremantle’s rising by 21% points to 54%, Essendon’s rising by 15% points to 35%, West Coast’s falling by 25% points to 22%, GWS’s falling by 23% points to 21%, and Richmond’s falling by 18% points to 20%.

Top 4 chances were also buffeted, with Sydney’s increasing by 15% points to 21%, Melbourne’s by 13% points to 96%, and Geelong’s by 11% points to 81%, and with Port Adelaide’s falling by 20% points to 34%, and Brisbane Lions’ by 16% points to 73%.

According to both the Standard and the Heretical Methodology, the Dees are now around 45% chances for the Minor Premiership, while the Dogs are around 35 to 40% chances.

STANDARD METHODOLOGY

HERETICAL METHODOLOGY

The range of Expected Wins using the Standard Methodology across the 18 teams moved to about 11.3 wins this week, while using the Heretical Methodology it came in at 11.8 wins.

The animation below shows how each team’s ladder probabilities have varied across the season so far.

Here’s that same data presented as stacked 100 percent bars - prettier, but probably less informative.

Across the 50,000 Standard Methodology simulations there are 14,459 different sets of teams playing Finals, treating different orderings of the same eight teams as a different set. No ordering appears in more than 117 replicates. If we ignore ordering, there are still 154 different sets of eight Finalists.

Amongst the teams currently in the Top 8, the estimated probability that any 5 through 8 of them play Finals is:

  • All 8: 7%

  • Only 7: 60%

  • Only 6: 33%

  • Only 5: 0.4%

Put another way, there’s about a 93% estimated chance that the teams playing Finals won’t be the current Top 8 teams. The main reason for this is the very low rating that MoSHBODS currently attributes to West Coast, which has them winning only an additional 2.2 of the remaining 6 games (Adelaide away, St Kilda home, Collingwood away, Melbourne home, Fremantle, and Brisbane Lions away)

TEAM AND POSITION CONCENTRATION

The HHI figures for the most recent Standard Methodology simulation replicates appear below.

(For information about the HHI, also see that previous blog linked to earlier).

We see a reduction of over one full spot in final ladder position uncertainty this week for Essendon, St Kilda, Adelaide, and Hawthorn, and of over two full spots for Melbourne and Fremantle. We also see an increase of over one full spot for Western Bulldogs.

Carlton, West Coast, Richmond, and GWS are the teams with greatest uncertainty about the positions in which they’ll finish on the ladder, each of them effectively competing now for about 8.5 ladder spots. North Melbourne, Melbourne, and Hawthorn have least uncertainty, and are all effectively competing for only about 2.5 to 3 spots.

After 16 rounds, the average team is still effectively competing for about 6 different ladder positions.

Last week again saw a range of increases and decreases in the uncertainty associated with various ladder positions, with the largest increase for 18th, and the largest decreases for 7th and 17th.

Positions 7th through 14th are now the ones that are associated with most uncertainty, and some of the top and tail positions - 1st and 2nd, 17th and 18th, and now also 5th and 6th - with least uncertainty.

There are now, effectively, about 2.7 teams vying for the Minor Premiership, and 2.3 battling for the Spoon.

To put these numbers in some historical context, we can compare their trajectory with that witnessed in the 2019 season.

We see that we’re in a similar position after 17 rounds as we were in 2019 for ladder positions 1st through 3rd, and 10th through 18th, but that we have effectively fewer teams competing for ladder positions 4th through 9th.

IMPORTANCE OF PERCENTAGE

The Standard Methodology simulations suggest that percentages remain relatively unlikely to decide key ladder positions.

There is now an estimated 40% chance that 8th and 9th will finish equal on competition points, a 14% chance that 8th and 10th will, and a 4% chance that 8th and 11th will.

There’s also about a 38% chance that the double-chance in the Finals will be determined by percentage.

WINS TO MAKE The 8 AND THE 4

Based on the Standard Methodology, the estimates of team chances of playing Finals should they finish on only 11 wins have generally increased, with most teams now better than even-money hopes with such a tally. West Coast, St Kilda, and Adelaide fare worst with just 11 wins. Team chances are all 90% or higher with 12 wins, but lowest for West Coast and St Kilda.

Looking next at making the Top 4, we see that teams’ chances range from about 20% to 60% with 14 wins, and 65% to 95% with 15 wins, with West Coast and St Kilda faring worst with only 14, and Port Adelaide and Sydney worst with 15 wins.

HOW MANY WINS TO FINISH WHERE

Now a look at what the Standard Methodology shows for the joint distribution of number of wins and final ladder position for each team.

WINS FOR A PARTICULAR LADDER POSITION

And, finally, an update on the distribution of wins associated with each ladder position.

It’s now very much the case that 11 wins rather than 12 is more likely to be associated with the team finishing 8th, and 15 wins remains more likely than 14 or 16 wins to be associated with the team finishing 4th.

GAME IMPORTANCE

Finally, let’s take a look at how the Standard Methodology estimates the importance of each of the remaining 54 games (see this blog for details about how these are calculated).

This week, again, I’m going to present the importance information by showing the 10 most important games for each team (except for North Melbourne, Melbourne, and Western Bulldogs, for whom no single game result can budge their finals chances from 0 and 1 respectively)

Round 18, then, includes:

  • Likely very important games for: St Kilda, Fremantle, Essendon, GWS, Richmond, and West Coast

  • Likely moderately important games for: Carlton

  • Likely marginally important games for: Sydney, Collingwood, and Gold Coast