2018 - Round 4 : Overs/Unders Update

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This week, the bookmakers are thinking even more like MoSSBODS and MoSHBODS, and are forecasting total scores of about 180 points per game, just 1 point per game more than the MoS twins.

From this we have:

MOST LIKELY HIGH-SCORING GAME

  • MoSSBODS & MoSHBODS : Richmond v Brisbane Lions
  • TAB and Centrebet : Essendon v Port Adelaide

MOST LIKELY LOW-SCORING GAME

  • MoSSBODS : GWS v Fremantle
  • MoSHBODS: West Coast v Gold Coast
  • TAB and Centrebet : GWS v Fremantle, and Adelaide v Collingwood

MOST LIKELY HIGH-SCORING TEAM

  • All : Richmond

MOST LIKELY LOW-SCORING TEAM

  • MoSSBODS : Fremantle and Gold Coast
  • MoSHBODS & TAB : Fremantle
  • Centrebet : Brisbane Lions

In a few of those comparisons, the relevant forecaster expects a number of teams or games to generate quite similar high or low scores, so a probabilistic view might be more helpful.

For this purpose again I've used simulations and MoSHBODS' team scoring opinions to estimate probabilities for each team finishing as the round's highest or lowest scoring, and likewise for each game finishing as the round's highest or lowest scoring.

With a replicate count of 1 million, the standard errors for these estimates are very small but we've no idea, of course, about whether the underlying model is biased in any significant way, so the added precision might just be homing us in on the wrong probabilities. In time, with enough data, we'll be able to quantify how well-calibrated MoSHBODS is in relation to this sort of probability estimating. 

This week we find that MoSHBODS' estimates suggest Richmond, Adelaide, Geelong, and GWS between them have a better than even-money shot at securing the round's high score, and that Fremantle, Collingwood, Gold Coast, and the Brisbane Lions have a similar collective shot at securing the low score.

Despite the Lions' roughly 10% chance of producing the round's low score, when we consider their score along with the Tigers', there's about a 20% chance that the Lions will play in the round's highest scoring game. Those two events, of course, are highly negatively correlated for the Lions. 

Four other games have a better than 10% chance of producing the round's highest total and five in total have a better than 10% chance of producing the round's lowest total.

WAGERS

MoSSBODS has gone with four bets this week, three of them unders wagers, and the fourth an overs bet in that Richmond v Brisbane Lions game. There's a high chance of rain in that match and the total has already drifted down from 184.5 to 181.5 at Centrebet, so Investors (who got 180.5 at the TAB) will have to hope that the scoring isn't too negatively affected by any inclement weather.

All of the overlays are single-digit figures this week (if we think of them as integers), including those for the games where we've wagers. 

PERFORMANCE TO DATE

Last week, despite a modest 1 from 3 performance when wagering, MoSSBODS did a good job of predicting scores and totals across the nine games.

It recorded the best mean absolute error (MAE) of the four forecasters in terms of proximity to the actual totals, and also recorded the best MAE for away team scores. Centrebet grabbed the low MAE for home team scores and for game margins.

Taken across the three rounds, the TAB remains best for game margins, but Centrebet is now best for home team scores, away team scores, and game totals.