2018 : Simulating the Final Ladder After Round 11
/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 three of the weekend's winners:
- Geelong (+0.8)
- Hawthorn (+0.8)
- GWS (+0.8)
The big losers were the teams the big gainers beat:
- Port Adelaide (-0.8)
- Gold Coast (-0.8)
- Adelaide (-0.8)
It's interesting to note that, as the number of games remaining diminishes, the range of changes in teams' Expected Win values from one week to the next is shrinking. For now at least, that's preserving the gap in Expected Wins for the teams around mid-table. Last week, just 2 Expected Wins separated Sydney in 4th from Adelaide in 9th. This week, the gap between 4th and 9th (which is now between Sydney and Hawthorn) is just under 1.8 Expected Wins.
In terms of likelihood of making the Finals, the week's big gainers were:
- Geelong (+14% points)
- Hawthorn (+13% points)
- GWS (+11% points)
The week's big losers were:
- Adelaide (-23% points, which makes it 42% points in the last two weeks)
- Port Adelaide (-16% points)
In the quest for a Top 4 spot, Geelong made the biggest gains (+11% points), while Port Adelaide made the biggest losses (-17% points).
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. (For information about how to interpret these measures, see this blog.)
Of all the teams', Adelaide's final ladder position saw the largest reduction in uncertainty this week, their loss to GWS leaving them almost 75% chances now to finish in one of positions 8th to 12th. Essendon and Fremantle also saw relatively large decreases in the uncertainty about where they'll finish the home and away season.
No team saw a significant increase in uncertainty this week, though Carlton, West Coast, St Kilda, and Sydney did see small increases.
Overall, looking across all 18 teams, we saw a slightly smaller decrease in uncertainty this week than we did last week, with the average Gini score rising by 5% in Round 11 compared to 6.6% in Round 10.
Looking next at each of the ladder positions, we see that all but two ladder positions became at least a little more confident about which team will occupy them come the end of the home and away season, the exceptions being 18th and 17th. That said, the overall levels of confidence about who will take these spots remain relatively high compared to other ladder positions.
Certainty increased most of all for positions 9th through 14th, although a slew of other positions saw increases of only slightly smaller amounts.
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 5% increase in the average Gini coefficient)
In absolute terms, highest certainty is now associated with the top three and bottom seven places on the ladder, and least certainty with positions 4th to 11th. Positions in the Finals, especially those in the bottom half of the 8, are still very much open.
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 slightly this week to about 70%. Geelong and North Melbourne are the only other teams with estimated conditional probabilities above 60% for this outcome. Their estimates fell this week too, however.
West Coast, whose remaining schedule includes games against Melbourne, Sydney, North Melbourne, Collingwood, Port Adelaide, Adelaide and GWS, are among the teams least likely to make the Finals should they finish on just 12 wins. This is because the nine losses they'd need to record to do this would likely include many of the other teams vying for a spot in the Finals and would push those teams closer to 13 wins themselves.
The Western Bulldogs and Fremantle also have relatively small estimated chances of making the Finals with just 12 wins, while thirteen wins makes every team estimated 90% or better chances for a spot in the Finals.
Looking next at the analysis for Top 4 finishes, we find that both Melbourne's and Richmond's estimated chances remain relatively high with just 14 wins, though Melbourne is now the only two team with an estimated greater than 50% chance of a Top 4 finish with only 14 wins.
Fifteen wins gives every team at least an estimated 75% chance of a spot in the Top 4, with Sydney, Port Adelaide and Hawthorn most likely to miss the Top 4 should they finish with 15 wins.
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 a number of team's estimated chances vary by as much as 15 to 20% points depending on whether or not some other team does or does not make the Final 8.
(Bear in mind, though, that the two estimates that define the range of any one of these arrows are each subject to sampling error, which could serve to shrink or extend the arrow's range in any one particular simulation run. I'm thinking about ways to best handle this.)
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. Matches involving two of GWS, Hawthorn, Adelaide and Geelong now fill the first five places on this list, as these are teams most likely to be vying for spots on the fringe of the Finals, which makes games in which they are opponents all the more important.
Games that were also on the Top 30 list last week are marked with an asterisk. Seventeen of the 27 games that were on last week's list and that weren't Round 11 games are still on the list.
Looking just at the next few rounds, we have the following counts of Top 30 games:
- Round 12: 3 (of 7 games)
- Round 13: 1 (of 6 games)
- Round 14: 2 (of 6 games)
