2016 Round 12 : Overs/Unders Update

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MoSSBODS still tends to predict smaller aggregates than does the TAB bookmaker, but this week the difference is under 2 goals in six of the games with the result that the Overs/Unders Fund is only active in three.

In the third of those games chronologically, the Saints v Blues game where the total was set at 180.5 points, I was a little late to the buffet and had to settle for a price of $1.80. That's the price you pay - literally - for being only a hobbyist punter. Since that bet was made the total on this game has been reset to 177.5 and the price restored to $1.90. Investors have, effectively, got a bet that's about 1 point better than this, since a $1.80 price is roughly equivalent to a 2 point deduction. Thus, out 180.5 at $1.80 is roughly the same as 178.5 at $1.90.

Anyway, the three Over/Under wagers make it 16 in total for the three Funds this week and leave Investors with a total of 11.7% of Original Funds at risk, the second-highest figure of the season to date.

Comparison of MoSSBODS with the TAB tells the usual story though, as alluded to earlier, MoSSBODS underestimation of aggregate scores relative to the TAB is somewhat smaller than in previous weeks.

On a team-by-team basis, MoSSBODS has 16 of the 18 teams scoring fewer points than does the TAB, though for only two teams is the difference greater than 2 goals: Hawthorn (25 points less) and Carlton (19 points less). Geelong and Collingwood are the only teams expected to score more by MoSSBODS than they are by the TAB, and in both cases the excess is under 9 points.

One other interesting feature this week is the relative strength of home teams as perceived by MoSSBODS compared to the TAB. In all but the weekend's final game pitting the Dees against the Pies, MoSSBODS forecasts larger victory margins or smaller losses for the home team than does the TAB. In most cases that difference is less than 2 goals, though in the Essendon v Hawthorn game it's 4 goals and in the West Coast v Adelaide game it's 2 goals.

The respective performances of MoSSBODS and the TAB so far this season have been:

  • Home Scores - MoSSBODS : MAE 21.3, Mean Error +8 / TAB : MAE 18.8, Mean Error +3
  • Away Scores - MoSSBODS : MAE 19.2, Mean Error +1 / TAB : MAE 20.2, Mean Error -5
  • Total Scores - MoSSBODS : MAE 27.9, Mean Error +9 / TAB : MAE 25.8, Mean Error -2
  • Margins - MoSSBODS : MAE 29.7, Mean Error +7 / TAB : MAE 29.2, Mean Error +8

Note that all errors are calculated as Actual less Predicted, so Home teams have, on average scored about 8 points more than MoSSBODS has expected. Part of that difference can be attributed to the unexpectedly high conversion rate of home teams this season. So far, they've converted 54.5% of their Scoring Shots into goals, well above the 53.3% that MoSSBODS expected based on teams' conversion rates in 2015.

In comparison, away teams have converted at a rate of 52.5%, a little under the expected 53.3%.