2017 : Simulating the Final Ladder and Final Series After Round 18

/

We've again seen some dramatic shifts in teams' estimated chances of finishing in the critical regions of the ladder.

Specifically, this week's 50,000 simulations of the remainder of the 2017 AFL season sees:

  • eight teams' Finals chances move by more than 5% points
  • four teams' Finals chances move by more than 10% points
  • seven teams' Top 4 chances move by more than 5% points
  • four teams' Top 4 chances move by more than 10% points

(For details on the methodology I've used in the simulations, please see this blog.)

RESULTS

The charts below summarise the distribution of ladder finishes for the 18 teams from the simulations run after the current round, Round 18, and Round 17. Note that the ordering of the teams is slightly different in the two charts, reflecting improvement or deterioration in some team's expected ladder finish.

AFTER ROUND 18

AFTER ROUND 17

In terms of Final 8 chances, the big winners this week were:

  • Melbourne: +15% points
  • Essendon: +10% points
  • Richmond: +8% points
  • Sydney: +8% points (up by 64% points now in the last six weeks)
  • Western Bulldogs: +7% points

The big losers were:

  • West Coast: -20% points
  • St Kilda: -19.5% points
  • Port Adelaide: -5% points

In terms of Top 4 chances, we had as winners:

  • Richmond: +17% points
  • Sydney: +14% points
  • Melbourne: +9.5% points

... and, as losers:

  • Port Adelaide: -22% points
  • GWS: -12.5% points (down by 31.5% points in the last three weeks)
  • Geelong: -7% points
  • West Coast: -5% points

The latest heat maps appear below and show a slight narrowing in the range of most-likely finishes for each team.

AFTER ROUND 18

AFTER ROUND 17

The only ladder positions for which we see a single team with a greater than 30% chance of securing it are:

  • 1st: Adelaide (75%)
  • 2nd: Geelong (33%)
  • 12th: Hawthorn (30%)
  • 13th: Collingwood (33%)
  • 17th: Carlton (33%)
  • 18th: Brisbane Lions (56%)

There are:

  • For 3rd through 6th: five or six teams with 10% or higher chances
  • For 7th and 8th: six or seven teams with roughly 9% or higher chances
  • For 9th through 11th: four or five teams with roughly 10% or higher chances

That's to be expected, I guess, when your competition ladder has positions 3rd through 11th separated by just 2 wins.

GAME IMPORTANCE

Next, let's update the game importance table. It shows, you'll recall, how each team's chances of making the finals varies depending on the result of each of the remaining games. The overall Weighted Ave Importance figure tells us the average amount by which the teams' finals chances are expected to change on the basis of the outcome of a particular game. A larger figure means that the game is expected to change teams' finals chances, on average, by a larger amount and hence is a more important game.

(For more details about the methodology and the rationale for it, again please see this blog.)

Next week's Dogs v Dons game stands out as the most finals-shaping game of the round and possibly the remainder of the season. Port Adelaide v St Kilda, and Kangaroos v Melbourne are the other fixtures likely to have the largest impact.

NUMBER OF WINS REQUIRED

Next, an update on the analysis looking at how likely it is that a team will play Finals given that it finishes the home-and-away season on exactly 11, 11.5, 12, 12.5 or 13 wins.

Recall that these estimates, because they're based on a sample of simulations, are subject to error (as are all of those in this blog), which here is reflected in the width of the segment.

What's most noticeable this week is the reduction in the likelihood that 11 wins will be enough for a finals berth for any team. Port Adelaide and Sydney have the highest probability of making the Top 8 should they finish on just 11 wins, but even their probabilities are only around 12%.

Twelve wins from Port Adelaide or Sydney, however, will almost certainly be enough to play finals, and would also make Essendon, Geelong, Collingwood, Melbourne and GWS better than even money chances. For Fremantle, Hawthorn, and St Kilda, 12 wins would give them only about 25% to 30% chances; they need 12.5 wins at least to have better than 90% chances of playing finals.

MOST LIKELY TOP 2s and top 4s

This week we'll again look at the team orderings most likely for the Top 2 and Top 4 spots.

Based on the latest simulations, the most likely final Top 2 is still Adelaide/ Geelong, which was the finishing order in about 31% of replicates, up about 10% points on last week's estimate.

The next most likely finish remains Adelaide/GWS, which again occurred in about 17% of replicates, while the third mostly likely is now an Adelaide/Richmond pairing with about an 11% probability.

Combined, the 10 most-likely Top 2s account for almost 90% of replicates and include now seven teams: Adelaide, Geelong, GWS, Port Adelaide and, in just one of the 10 most-likely finishes each, Richmond, Sydney and Melbourne.

A much broader range of Top 4s remain plausible according to the simulations, the 10 most likely quartets accounting for only 22% of replicates. 

Top of the list is still an Adelaide/GWS/Geelong/Port Adelaide finish, though this ordering now appears only in about 3% of replicates.

The next most likely ordering involves the same four teams but drops GWS back into 4th.

SIMULATIONS OF THE FINALS SERIES

Applying the methodology as described in last week's blog to the 50,000 final ladders produced by our original simulations yields the following results.

Adelaide remain favoured by the simulations to take out both the Minor Premiership (75% chance) and the Flag (30% chance). Sydney, Geelong and Port Adelaide are all assessed as being about 13 to 14% chances of winning the Flag, though Sydney more often has to achieve this result from the bottom half of the final 8.

In this final 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).

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

  • Lose in a Preliminary Final: Port Adelaide, GWS, Geelong and Adelaide
  • Lose in a Semi Final: Richmond and Sydney (though this outcome is only slightly more likely than losing in a Preliminary Final for Sydney)
  • Lose in an Elimination Final: Melbourne
  • Miss the Finals: all other teams