Matter of Stats

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2011 - Simulations After Round 20

First let's take a look at what our Projection Pursuit Regression (PPR) model now thinks about the margins for the remaining games.

Round 20 margins went pretty much as the PPR Model predicted - its Mean Absolute Prediction Error was a very creditable 30.3 points per game which would have ranked it second amongst MAFL's Margin Predictors - so there's little change in its predictions for the remainder of the home-and-away season.

For the Round 21 contests the biggest changes were a 5.9 point adjustment in the predicted victory margin of the Blues over Freo, and a 5.6 point adjustment in the Eagles' predicted victory margin over the Dees.

Looking across the remainder of the season, no predicted victory margin has changed by more than 3.3 points and in only one game has the predicted winner changed: the Carlton v Hawthorn clash of Round 22 for which Carlton are now considered narrow favourites by the PPR Model.

The predicted margin for this game is just 0.6 points, making it the game most likely to finish in a draw according to the PPR Model. In contrast, the Pies v Lions matchup in that same round is considered by the PPR Model to be least likely to finish in a draw since the Model's predicted victory margin for the Pies for that game is almost 80 points.

There's still considerable potential for other close finishes, however, as nine of the remaining 32 games are predicted to be won by fewer than 12 points according to the PPR Model, and four more are predicted to be won by fewer than 18 points. Twelve games are predicted to be won by more than 30 points.

On then to the projected ladder finishes where we find little change is the teams' minor premiership, top 4 and Wooden Spoon chances compared to last week, but considerable change in the relative chances of the teams vying for positions in the bottom half of the top 8.

Essendon did most for their finals aspirations in pipping the Swans by a point. They've now a 66% chance of making the finals compared with the 37% chance they were assessed as having prior to last round.

(Remember that most images on the MAFL site can be clicked to open a larger version. The results on the left are the latest simulations; those on the right are last week's.) 

Other teams to increase their chances of playing finals footy were the Saints (up from 88% to 95%) and the Dogs (up from 0% to 5% merely by not playing).

Aggregate chances being a zero-sum game, the Dons', Saints' and Dogs' gains must be some other teams' losses. Three teams each suffered 11-12% point reductions in their finals chances: Fremantle(down from 28% to 16%), Melbourne (down from 20% to 9%) and Roos (down from 27% to 16%). 

Given current TAB Sportsbet prices and these simulation results there appears to be value as follows: 

  • Carlton at $3.25 for a top 4 finish (only a small edge here)
  • St Kilda at $1.10 for a top 8 finish (also only a small edge)
  • Gold Coast at $4.50 for the Spoon (reasonable value here)
  • Fremantle at $7.00 for a top 8 finish (this bet represents the largest edge of all four)