2018 : Simulating the Final Ladder After Round 13

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Updated final home and away ladder simulations appear below.

(For details on the methodology, see this post from earlier.)

With relatively few rounds in the home and away season left, it's hard now for teams to add or lose more than half a game.

The only teams to gain more than half a game this week were:

  • Hawthorn (+0.8)
  • Fremantle (+0.6)

And, the only teams to lose more than half a game were the teams those two beat:

  • Adelaide (-0.7)
  • Carlton (-0.6)

Only nine teams are now expected to finish with a better than 50% win-loss record, with Adelaide falling away and GWS now expected to win only 11.9 games. It's still fairly likely though that percentage will decide some of the lower positions in the Top 8. For example, about 36% of the latest replicates had the team in 9th separated on percentage from the team in 8th.

In terms of likelihood of making the Finals, the week's big gainers were:

  • Hawthorn (+17% points)
  • Port Adelaide (+6% points, which makes it 16% across the last two weeks)

The week's big losers were:

  • Adelaide (-11% points, which makes over 60% points in the last four weeks)
  • Geelong (-6% points)

In the quest for a Top 4 spot, Hawthorn made the biggest gains (+7% points), slightly ahead of Port Adelaide (+6% points), while Geelong made the biggest losses (-10% points).

TEAM AND POSITION CONCENTRATION

This week's Gini concentration measures appear below, and reflect once again increasing certainty in our knowledge about which teams will finish where at the end of the home and away season. (For information about how to interpret these measures, see this blog.)

Carlton, Adelaide and Richmond saw the largest increases in certainty about their final ladder positions this week, though Adelaide still retains a moderate level of uncertainty relative to the all-team average. Carlton has the greatest certainty of any of the teams about its likely final ladder finish.

West Coast's position saw the largest increase in uncertainty this week - so much so, in fact, that its position is now less certain than it was as far back as Round 9. Melbourne and Collingwood also became a little less certain about where they'll finish and, in absolute terms, have a wider range of feasible finishes than most teams. Port Adelaide has the widest range, however, with 9% or higher chances of finishing in any of positions 3rd to 9th.

Overall, looking across all 18 teams, we saw a slightly larger decrease in uncertainty this week than we did last week, with the average Gini score rising by 2% compared to 1.5% in Round 12. That's still well below the 5% and 6.6% reductions we saw in Rounds 10 and 11, however.

 

Looking next at each of the ladder positions, we see some relatively significant reductions in the uncertainty about ladder positions 11th, 12th, 15th and 18th, and some smaller reductions for ladder positions 7th, 13th and 14th.

There were no significant increases in the uncertainty about any of the 18 positions, and no increases at all except for positions 2nd, 4th and 10th.

Across all 18 ladder positions, the average increase in certainty this week is similar to that we saw for the team-based view (viz about a 2% increase in the average Gini coefficient)

In absolute terms, highest certainty is still associated with the top two and bottom seven places on the ladder, and least certainty with positions 3rd to 11th. The bottom three Finals positions remain the least certain of all.

WINS REQUIRED

Below are the updated estimates of teams' likelihood of making the Finals depending on the number of wins that they record.

(Recall that, because we're working with a sample of simulated final ladders, our estimates have sampling error, so we show them as 95% confidence intervals here with the mean estimate shown as a point. In some cases, our sample is so large that the interval essentially collapses to a point, at least to the resolution shown here.)

Geelong are now the team most likely to make the Finals should they finish on 12 wins, but the estimated conditional probability of them doing this is below 50%. Fremantle, Essendon and the Western Bulldogs are the teams least likely to make the Finals should they finish on just 12 wins. 

Looking next at the analysis for Top 4 finishes, we find that no team now has an estimated greater than about 30% chance of such a finish with only 14 wins. Richmond, Melbourne and Geelong have the highest estimated probabilities, while West Coast, Sydney, Port Adelaide and Fremantle have the lowest at around 15%.

Fifteen wins gives every team except Port Adelaide and Sydney at least an estimated 75% chance of a spot in the Top 4.

Next, we explore the inter-team dependencies in the composition of the final 8 by estimating the probability that a particular teams makes the 8 conditioned on some other team making or missing the 8.

These are shown in the chart below, as usual, as arrows with the base of an arrow marking the estimated probability that a team makes the 8 conditioned on a nominated team missing the 8, and the arrow head marking the estimated probability that a team makes the 8 conditioned on a nominated team making the 8.

We see this week that GWS, Hawthorn, and North Melbourne are still the teams most dependent on the fates of the other teams in the mix for a Top 8 finish, though Geelong is now fairly dependent too. All four of those teams are about 12-14% chances to finish 8th, and 10-17% chances to finish 9th.

We can do the same analysis for positions in the Top 4, which we do below.

Here we find that Collingwood, Geelong, Melbourne, Port Adelaide and Sydney are the teams whose fates are most tied to others'. Richmond and West Coast are both highly likely to make the Top 4, and Hawthorn and North Melbourne fairly unlikely, independent of the fates of other teams.

GAME IMPORTANCE

Lastly, here's the updated list of the 30 most important games remaining in the fixture on the basis of their expected impact of all 18 teams' finals chances. North Melbourne has five games in the Top 10, GWS four, and Sydney and Hawthorn two each.

Games that were also on the Top 30 list last week are marked with an asterisk. Twenty-six of the 29 games that were on last week's list and that weren't Round 13 games are still on the list. 

Looking just at the next few rounds, we have the following counts of Top 30 games:

  • Round 14: 2 (of 6 games)
  • Round 15: 3 (of 9 games)
  • Round 16: 2 (of 9 games)