Matter of Stats

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2021 : Simulating the Final Ladder After Round 21

The latest simulations of the final home and away ladder appear below.

Using the Standard Methodology we have:

  • six teams certain to play Finals, four teams with chances roughly in the 40 to 50% range, two with chances in the 8 to 12% range, and one team with a 1-in-500 chance

  • one team certain to finish Top 4, three teams with chances in roughly the 90 to 95% range, one team with a 20% chance, and another with a 3% chance.

Under the Heretical Methodology we have:

  • six teams certain to play Finals, four teams with chances roughly in the 40 to 55% range, two with chances in the 8 to 11% range, and one team with a 1-in-500 chance

  • one team certain to finish Top 4, three teams with chances in roughly the 85 to 95% range, one team with a 25% chance, and another with about a 1-in-40 chance.

(For details about the methodologies I’ve used, see this earlier blog.)

LADDER FINISHES

Team Expected Wins under the Standard Methodology grew by 0.9 wins this week for Essendon, and fell by 0.9 wins for Geelong.

The big moves in terms of Finals chances were Essendon’s increase by 34% points to 53%, GWS’s increase by 19% points to 39%, Fremantle’s decrease by 31% points to 12%, West Coast’s decrease by 19% points to 46%, and Carlton’s decrease by 15% points to almost zero.

In Top 4 chances we saw Port Adelaide’s increase by 20% points to 87%, Brisbane Lions’ increase by 12% points to 20%, and Sydney’s decrease by 30% points to 3%.

According to both the Standard and the Heretical Methodology, the Dees are now around 50% chances for the Minor Premiership, the Dogs around 30%, and the Cats around 20%.

STANDARD METHODOLOGY

HERETICAL METHODOLOGY

The range of Expected Wins using the Standard Methodology across the 18 teams moved to about 11.7 wins this week, while using the Heretical Methodology it came in at about 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 in a format that I still don’t think has a name.

(I think I prefer these with probability on the y-axis. Thoughts?)

Across the 50,000 Standard Methodology simulations there are 1,694 different sets of teams playing Finals, treating different orderings of the same eight teams as a different set. No ordering appears in more than 1,422 replicates. If we ignore ordering, there are still 20 different sets of eight Finalists.

Amongst the teams currently in the Top 8, the estimated probability that any 6 through 8 of them play Finals is:

  • All 8: 15%

  • Only 7: 55%

  • Only 6: 30%

Put another way, there’s about an 85% estimated chance that the teams playing Finals won’t be the current Top 8 teams.

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).

Teams’ final ladder positions are continuing to become less uncertain. This week, for example, saw a 4.1 spot reduction in final ladder position uncertainty for Carlton, a 2.4 spot reduction for Essendon, and a 1.6 spot reduction for Sydney. The only sizeable increases were a 1.4 spot increase for West Coast, and a 0.9 spot increase for Western Bulldogs,

GWS, Fremantle, Richmond, St Kilda, and West Coast are now the teams with greatest uncertainty about the positions in which they’ll finish on the ladder, each of them effectively competing now for about 5 to 6 different ladder spots. North Melbourne and Sydney have least uncertainty, with each now effectively competing for only 1.2 to 1.6 spots.

After 18 rounds, the average team is now effectively competing for about 3.8 different ladder positions.

Most ladder positions again saw decreases in the effective number of teams competing for them last week, with none seeing an increase of more than 0.7 teams (7th). Particularly large decreases in uncertainty were registered by 13th (-2.7 teams), 12th (-1.5), and 11th (-1.4).

Positions 8th through 12th are now the ones that are associated with most uncertainty, and 1st, 4th to 6th, 13th and 18th with least uncertainty.

There are now, effectively, about 2.8 teams vying for the Minor Premiership, and 1.2 battling for the Spoon.

IMPORTANCE OF PERCENTAGE

The Standard Methodology simulations suggest that percentages are now slightly less likely to decide 8th spot on the ladder.

There is now an estimated 40% chance that 8th and 9th will finish equal on competition points, a 16% chance that 8th and 10th will, and a 10% chance that 8th and 11th will.

There’s also still about a 27% chance that the double-chance in the Finals will be determined by percentage.

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 is now very likely that 11 wins will be associated with the team finishing 8th and also the case that 16 wins rather than 15 will be associated with the team finishing 4th.