2022 : Simulating the Finals Series After Round 24

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Just six games now to simulate for games played over a three-week period, with Sydney now guaranteed a home Preliminary Final against an interstate team, and Geelong only enjoying that same benefit if the Lions spring the upset this week and defeat the Dees. That has quite a dramatic impact on the simulation results, as we’ll see.

(For details about the methodology, see this blog post and also refer to this one from earlier that talks about an alternative approach to adding time-based variability to team ratings that I’m currently trialling)

Applying the (conventional) “traditional” methodology to 10,000 of the 50,000 home and away season simulation replicates yields the following chart showing teams’ Finals fate overall and as a function of the teams they are defeated by during the Finals or, if they win the Grand Final, the team that they defeated.

Overall, we see that the teams fall fairly naturally into seven groups:

  • Sydney: just under 2-in-5 chances for the Flag and just over 3-in-4 chances to make the Grand Final.

  • Geelong: just over 7-in-20 chances for the Flag and just under 2-in-3 chances to make the Grand Final.

  • Melbourne: about 1-in-7 chances for the Flag and about 1-in-3 chances to make the Grand Final

  • Collingwood: about 1-in-14 chances for the Flag and just over 3-in-20 chances to make the Grand Final

  • Fremantle: about 1-in-50 chances for the Flag and 1-in-16 chances to make the Grand Final

  • Brisbane Lions: about 1-in-100 chances for the Flag and 1-in-33 chances to make the Grand Final

Geelong and Sydney both win more than 50% of the Grand Finals that they make (although Sydney only just).

WEEK OF ELIMINATION IN FINALS

In this next chart we look at teams' chances for various Finals finishes, ignoring their home and away ladder positions (ie we focus solely on the heights of the bars in the previous chart). The numbers shown inside a cell are the percentage of simulation replicates (multiplied by 100) in which the specified team went out in the specified week of the Finals.

We see here that, if we define the season in terms of the five events listed above plus "Miss the Finals", the most-likely finishes for each team are estimated to be:

  • Win Grand Final: Sydney (just)

  • Lose in a Preliminary Final: Geelong (just), Melbourne, and Collingwood

  • Lose in a Semi-Final: Fremantle and Brisbane Lions

GRAND FINAL PAIRINGS 

In this final chart we look at all of the Grand Final pairings that occurred in at least one of the simulation replicates. The numbers shown inside a cell are the percentage of simulation replicates (multiplied by 100) in which the team named in the row defeated the team named in the column in the Grand Final.

We see that the most common Grand Final pairing is Geelong and Sydney, which occurs in almost 1-in-2 replicates with Geelong winning about 55% of them. Next, we have the Melbourne/Sydney pairing, which occurred in about 1-in-4 replicates, with Sydney winning about 60% of them, then Geelong/Collingwood, which occurred in about 1-in-10 replicates, with Geelong winning about 60% of them as well..

CHARTS FOR THE ALTERNATIVE METHOD

Applying the alternative methodology (see this post for details) to both the home and away season simulations and then to 10,000 of those for the purposes of simulating the Finals yields the following, alternative outputs.

Geelong and Sydney fair slightly better under this methodology.

Overall, the team-by-team main differences are:

  • Sydney’s Flag chances increase from about 39% to 44%

  • Geelong’s Flag chances increase from about 36% to 39%

  • Melbourne’s Flag chances decrease from about 14% to 12%

  • Collingwood’s Flag chances decrease from about 7% to 5%

  • Fremantle’s Flag chances decrease from about 2% to 1%

  • Brisbane Lions’ Flag chances decrease from about 1% to under 0.5%

For completeness’ sake, here are the Grand Final matchup numbers under this alternative methodology:

We now have:

  • Geelong v Sydney Grand Final: about 5-in-9 replicates, Geelong wins just under 60% (compared with 1-in-2 and about 55%)

  • Melbourne v Sydney Grand Final: about 3-in-10 replicates, Sydney wins about 66% (compared with 1-in-4 and about 60%)

  • Geelong v Collingwood Grand Final: about 1-in-14 replicates, Geelong wins just over 60% (compared with 1-in-10 and about 60%)