Matter of Stats

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2019 : Simulating the Final Ladder After Round 10

The results of the latest 50,000 simulations appear below.

(If you’re curious about the methodology used to create them, you can start here.)

RESULTS

The likely battle for the lower half of spots in the Final 8 is possibly best highlighted by the fact that, in the most-recent simulations, 7 teams are expected to record between 10.5 and 12.3 wins, and 12 teams have a least a 1 in 3 shot at finishing in a Finals position.

The week’s biggest losers in terms of Expected Wins, according to the simulations, were Adelaide, Port Adelaide and the Western Bulldogs, each of which dropped by 0.7 Expected Wins, while the biggest gainers were West Coast and Hawthorn, who both climbed by 0.7 Expected Wins.

Looking at the simulations through the lens of making the Finals, we have a similar story:

LOSERS

  • Port Adelaide (down 14% points)

  • Adelaide (down 12% points)

  • Western Bulldogs (down 10% points)

GAINERS

  • Hawthorn (up 14% points)

  • West Coast (up 14% points)

Geelong remain better than even-money chances for the minor premiership, with Collingwood still roughly 3/1 propositions for that spot.

DETAILED LADDER FINISH ESTIMATES

The detailed view of each team’s estimated probability of finishing in each of the 18 possible ladder positions appears below. Blank cells represent ladder finishes that did not occur even once in the 50,000 simulations, while cells showing a value of 0 represent estimated probabilities below 0.05%.

We see in this heatmap the high levels of uncertainty about mid-table ladder positions, with many teams in the 9 to 11% range for positions 6th through 12th.

WINS REQUIRED FOR TOP 8 AND TOP 4

This week we’ll look again at what the simulations reveal about the likelihood of each team playing Finals or finishing Top 4 depending on the number of wins it records.

Here, firstly, is the analysis for a Finals berth.

About half of the teams have 25% or better chances of playing Finals with just 11 wins, but all have 75% or better chances with 12 wins. Due to the nature of their remaining schedule, and their current percentage, West Coast still has the smallest chance (about 10%) of playing Finals after registering only a 12 and 12 home-and-away record. They have a relatively poor percentage (101.6) and play only Richmond and Collingwood (once each) of the teams above them on the ladder across the remainder of the home-and-away season.

By contrast, GWS has the highest chance (roughly 35%) of playing Finals with a 12 and 12 home-and-away record. They have the second-best percentage in the competition (130.0) and face Richmond, Collingwood, and Brisbane Lions in their remaining games.

Next, let’s look at the analysis for Top 4.

Here we see that most teams have a 25% or lower chance of finishing Top 4 with a 13 and 9 record (with GWS the exception), but most have about a 75% or higher chance with a 14 and 8 record. Brisbane Lions, West Coast, St Kilda and Richmond have the lowest chances of a Top 4 finish should they win only 14 home-and-away games.

LIKELIHOOD OF PERCENTAGE DETERMINING POSITIONS

Next we’ll again analyse how likely it is that key positions on the final home-and-away ladder will be determined by percentage because the teams in those positions finish tied on competition points.

This week, 4th and 5th are separated by percentage in about 40% of the simulations (down 3% points), and that 8th and 9th are separated by percentage in about 52% of the simulations (no change). So, it’s slightly more likely than not that the last spot in the Finals will be determined based on the percentages of the teams in contention.

TEAM AND POSITION CONCENTRATION

As mentioned for a few weeks now, one way of measuring how much uncertainty there is in the competition is to use the Gini measure of concentration commonly used in economics for measuring income inequality to quantify the spread of each team's estimated final ladder positions across the 50,000 simulation replicates, and to quantify the concentration in the probabilities across all the teams vying for any given ladder position.

This week saw the uncertainty about the final ordering of the teams reduced again, with the Gini coefficients moving, roughly, from 0.51 to 0.54.

At the team level, we saw reductions in uncertainty for every team except North Melbourne, with the largest relative reductions for West Coast, Western Bulldogs, and Richmond.

Even with the reductions, St Kilda, Essendon, Hawthorn, Port Adelaide and Fremantle have the most uncertainty, while Geelong, Carlton, Collingwood, and Gold Coast still have most certainty about their eventual ladder finishes.

Next, if we adopt a ladder position viewpoint, we see that 1st and 18th remain the positions with the narrowest range of likely occupants at season's end, with about 80% chances that either of two teams will occupy them at season’s end, whilst positions 6th through 14th continue to have the widest range of possible tenants, with 9, 10 or 11 teams all having estimated 5% or higher chances of occupying them at the end of the season.

Looking more broadly, we see that every ladder position became more certain about which team will occupy it come the end of the home-and-away season. The biggest relative increases in certainty were for positions 3rd, 8th, 9th and 10th.

GAME IMPORTANCE

Here are the updated assessments of the 30 most-important games between now and the end of the home-and-away season. (See this blog for details about how these are calculated.)

This week, 21 of the Top 30 are common to last week’s list, as well as 13 of the Top 14.

In terms of the temporal distribution of these games, we now have:

  • Rounds 11 to 14: 6 games from 27 (22%)

  • Rounds 15 to 18: 8 games from 36 (22%)

  • Rounds 19 to 23: 16 games from 45 (36%)

By team we have:

  • 10 games involving Port Adelaide

  • 8 games involving Adelaide

  • 6 games involving Essendon or Hawthorn

  • 5 games involving Fremantle, St Kilda, or Western Bulldogs

  • 4 games involving Brisbane Lions or West Coast

  • 2 games involving North Melbourne or Richmond

  • 1 game involving Carlton, Collingwood, or Sydney

  • 0 games involving Geelong, GWS, Gold Coast, or Melbourne

We can again see the commonsense of this list when we compare it with the simulated probabilities for teams finishing in 8th or 9th, which are:

  • 22%: Adelaide

  • 21%: Port Adelaide

  • 20%: Hawthorn and Essendon

  • 19%: Brisbane Lions, St Kilda, and Fremantle

  • 16%: West Coast

  • 12%: Western Bulldogs

No other team has a higher than 10% estimated probability of finishing in 8th or 9th combined.