Matter of Stats

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Simulating the Finalists and Finals for 2016 After Round 22

The outputs of this week's simulation run starkly highlight the differences between MoSSBODS' and the TAB Bookmaker's opinions about a number of teams that will play in the Finals.

In the race for the Minor Premiership, for example, the TAB has Adelaide priced at $7, which makes MoSSBODS' 18% assessment of the Crows' chances look extremely attractive. But, for the Crows to finish 1st, realistically we'd need:

  • Sydney to lose and Adelaide to win, or 
  • Adelaide's victory margin over West Coast to be about 7 to 11 goals greater than Sydney's over Richmond

MoSSBODS reckons that scenario would occur about two times in 11 were the weekend's games to be played many times over. The TAB Bookmaker, alternatively, is banking that it would occur less often than about one time in 15.

Similarly, in the hunt for Top 4 spots, MoSSBODS rates the Dogs as about 12% chances while the TAB Bookmaker has them priced at $26. A Dogs Top 4 finish requires:

  • Hawthorn to lose to Collingwood
  • GWS to lose to the Kangaroos
  • West Coast to lose to Adelaide
  • Fremantle to lose to the Western Bulldogs

As well, the Dogs' victory margin needs to be sufficiently large to drive its percentage above the Hawks'. If we assume that the Hawks were to lose, say 70-80, the Dogs would need to win by about 25 points to achieve this.

MoSSBODS' higher probability for this scenario is due to a combination of:

  • A lower assessment of Hawthorn's chances (62% MoSSBODS, 79% TAB)
  • A higher assessment of the Roos' chances (49% MoSSBODS, 33% TAB)
  • A higher assessment of Adelaide's chances (89% MoSSBODS, 74% TAB)
  • A lower assessment of Fremantle's chances (18% MoSSBODS, 24% TAB)

Those individual probabilities, assuming independence, make the joint probability of the four requisite results 13.5% for MoSSBODS and 2.5% for the TAB. To arrive at a final probability for the Dogs' making the Top 4 requires one last assessment about the margins in the Hawks' and Dogs' games being sufficient to see the Dogs' percentage rise above the Hawks'.

In the end, MoSSBODS' assessment of that event sees the probability reduced to about 12%. Presumably, the TAB's estimate would, instead, be something like 2%, which makes that $26 price look very unattractive.

Turning away from considerations about only the top teams, let's have a quick look at this week's Dinosaur Chart.

We see here that most teams are now strong favourites for one or maybe two ladder finishes, though GWS and Hawthorn are notable for the broader range of plausible ladder finishes accessible by them.

That observation is even clearer in the team heat map, which appears below.

TOP 2s, 4s AND SO ON

A Sydney-Adelaide 1-2 finish appeared in two-thirds of the simulation replicates this week, and an Adelaide-Sydney finish cropped up in about 11% more, split by a Sydney-Geelong 1-2 finish, which occurred in almost 12%

In all, Sydney appeared in six of the Top 10 pairings, Adelaide and Geelong in five, Hawthorn in three (and always in 2nd), and GWS in one.

Combined these Top 10 pairings account for about 99.5% of all replicates.

The 10 most common Top 4s account for a smaller proportion of the replicates - about 80% - with the commonest of all, a Sydney/Adelaide/Geelong/Hawthorn finish, representing over one-third of them.

Swapping GWS for Hawthorn in 4th accounts for another 10%, and swapping the Western Bulldogs for Hawthorn another 9%.

GWS finishes as high as 3rd in one of the quartets, and Hawthorn does the same in five of them. The Dogs appear in only one quartet - the one mentioned in the previous paragraph - and this single ordering accounts for 9% of their 11.9% assessed chances.

The remaining uncertainty over most of the spots in the Top 8 means that a relatively large number of final orderings remain possible, the most likely of which, according to the simulation, is Sydney/Adelaide/Geelong/Hawthorn/Western Bulldogs/GWS/West Coast/Kangaroos. That specific ordering appeared in about 1 replicate in 7.

Another, almost equally-common ordering sees the Dogs and Giants switch 5th and 6th, this version appearing about 13% of the time.

Lastly, if we focus solely on positions 5th to 8th, we find that the Top 10 orderings account for just over 90% of replicates. The most common finish represents almost one-quarter of replicates and is Dogs/Giants/Eagles/Roos.

It's interesting to note the high level of variability about 5th spot on the ladder that is demonstrated by these projections, with six different teams appearing in 5th in at least one of the Top 10 orderings. Only Sydney and the Kangaroos from the almost-certain final Top 8 fail to appear in these orderings at least once.

FINALS SIMULATIONS

The simulation results for the Finals also highlight MoSSBODS' different assessments of team abilities relative to the TAB.

Adelaide is now almost a 50% chance for the Flag, according to MoSSBODS, though their price on the TAB is currently $3.50, making them seemingly very attractively priced in this market.

The TAB, instead, has Sydney as Flag favourites, priced at $3.25, just a little shorter than the Crows. Geelong and Hawthorn are both on the third line of betting at the TAB and priced at $5.50, though MoSSBODS has the Cats as 17% chances and the Hawks as only 7% - and only slightly more likely to win the Flag than GWS.

Adelaide's most likely finish according to MoSSBODS is a Grand Final win, Sydney's, Geelong's and Hawthorn's a loss in a Preliminary Final, GWS' a loss in a Semi-Final, and the Western Bulldogs', West Coast's and the Roos' a loss in an Elimination Final, although a Dogs loss in a Semi-Final is about as likely.

The Crows, as shown in the table below and which is drawn from the simulations, are about equally likely to win the Flag should they finish in any of the Top 4 spots, though slightly less so if they finish in 3rd or 4th. They would see their prospects halved in the unlikely event that they finished in 5th, an outcome that appeared in only 3% of replicates.

Such an outcome would require that:

  • Adelaide loses to West Coast
  • Geelong beats Melbourne
  • Hawthorn beats Collingwood
  • GWS beats the Kangaroos

Even using current TAB head-to-head prices, that scenario has only about an 11% chance of occurring.

While the Crows' chances roughly halve if they miss the Top 4, every other team sees their Flag chances roughly quarter should they do the same.

Finally, let's review the results for Grand Final quinellas.

An all-avian Crows v Swans game is currently assessed as being most likely, that pairing showing up in almost 30% of replicates.

Next-most common is a Crows v Cats matchup, which appears in a bit over 1 replicate in 5.

All up, 28 different pairings appeared at least once in the replicates, only five of which showed up often enough to make their TAB price look like value:

  • Adelaide v Geelong at $6.50
  • Adelaide v GWS at $11
  • Adelaide v Western Bulldogs at $51
  • Geelong v Western Bulldogs at $151
  • Western Bulldogs v GWS at $251

Here too, MoSSBODS' high rating of the Crows and the Dogs relative to the TAB is very apparent.

Also, as far as MoSSBODS is concerned, a Hawks v Swans GF offers the nearest to even-money matchup, such a contest projected as having the Hawks 51% favourites. In contrast, the most lopsided an somewhat likely GF would see Adelaide face West Coast, a pairing that would see the Crows start as almost 70% favourites.