2018 : Simulating the Final Ladder After Round 12
/Updated final home and away ladder simulations appear below.
(For details on the methodology, see this post from earlier.)
In terms of Expected Wins, the week's big gainers were:
- Collingwood (+0.9)
- Port Adelaide (+0.7)
The big losers were, again this week, the teams the big gainers beat:
- Melbourne (-0.9)
- Richmond (-0.8)
Ten teams are currently expected to finish with a better than 50% win-loss record, Adelaide narrowly failing to make it 11 with their expected 10.7 wins. It seems fairly likely that percentage will decide some of the lower positions in the Top 8. In fact, almost 40% 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:
- Collingwood (+10% points)
- Port Adelaide (+10% points)
- GWS (+10% points, which makes it 21% across the last two weeks)
The week's big losers were:
- North Melbourne(-16% points)
- Adelaide (-13% points, which makes over 50% points in the last three weeks)
In the quest for a Top 4 spot, Collingwood made the biggest gains (+17% points), with Sydney (+14%) and Geelong (+10%) also significantly lifting their chances, while Melbourne made the biggest losses (-25% points) and North Melbourne (-12%) also fell significantly.
TEAM AND POSITION CONCENTRATION
This week's Gini concentration measures appear below, and reflect increasing certainty in our knowledge about which teams will finish where at the end of the home and away season, albeit at a much lower rate this week. (For information about how to interpret these measures, see this blog.)
A range of teams saw roughly equivalent increases in the certainty of their final ladder positions this week: Brisbane Lions, Gold Coast, St Kilda, Western Bulldogs, Fremantle, Essendon, and Adelaide.
Richmond and Melbourne both saw relatively significant decreases in certainty this week, though Richmond are still 86% chances to finish somewhere in the Top 4. Melbourne are now 10% chances or greater to finish in any of the spots from 2nd to 7th.
Overall, looking across all 18 teams, we saw only a small decrease in uncertainty this week, with the average Gini score rising by just 1.5% compared to 5% in Round 11.
Looking next at each of the ladder positions, we see some relatively significant reductions in the uncertainty about ladder positions 11th through 13th, and some smaller reductions for ladder positions 14th through 16th
We also saw moderate increases in the uncertainty about positions 1st through 3rd after Melbourne and Richmond losses, and Collingwood and Geelong wins. 1st and 2nd places still have relatively low levels of uncertainty compared to other ladder positions, however.
Across all 18 ladder positions, the average increase in certainty this week is similar to that we saw for the team-based view (viz a little over a 1% increase in the average Gini coefficient)
In absolute terms, highest certainty is now 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 are 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.)
Melbourne remain the team most likely to make the Finals should they finish on 12 wins, but the estimated conditional probability of them doing this declined again this week to be now only just over 50%. Geelong and Richmond are the only other teams with estimated conditional probabilities of about the same size. For almost every team then, 12 wins will make them less than even money chances for a spot in the Finals.
Fremantle, West Coast and the Western Bulldogs are the teams least likely to make the Finals should they finish on just 12 wins. The Dogs, therefore, probably need to win nine of their remaining 11 games to make the Top 8, while the Dockers and Dons probably need to win eight of their remaining 10 games.
Looking next at the analysis for Top 4 finishes, we find that no team now has an estimated greater than 50% chance of such a finish with only 14 wins. Richmond have the highest estimated probability of around 40%.
Fifteen wins gives every team except Port Adelaide and Hawthorn 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 the teams most dependent on the fates of the other teams in the mix for a Top 8 finish, with all three of them currently considered to be 10% or better chances of finishing in any of the positions 7th through 10th.
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. Five of GWS' games from Rounds 15 through 23 are now amongst the 10 most important.
Games that were also on the Top 30 list last week are marked with an asterisk. Twenty of the 27 games that were on last week's list and that weren't Round 12 games are still on the list.
Looking just at the next few rounds, we have the following counts of Top 30 games:
- Round 13: 1 (of 6 games)
- Round 14: 3 (of 6 games)
- Round 15: 2 (of 9 games)
