2018 - Round 19 : Overs/Unders Update

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This week, according to the two bookmakers, we should expect about 165 points per game, which is roughly one point per game below the season average.

The MoS twins have slightly higher expectations, almost entirely because they see about three or four more goals being scored in the Giants v Saints game than do the bookmakers. Their overall average is 168 to 169 points per game, which is 3 to 4 points higher than the bookmakers'.

Another difference between the two pairs is that the bookmakers expect only three games to produce totals over 170 points, while the MoS twins expect four or five to top this mark.

MOST LIKELY HIGH-SCORING GAME

  • MoSSBODS & MoSHBODS : Adelaide v Melbourne (184)
  • TAB & Centrebet : Geelong v Brisbane Lions (177.5 to 178.5)

MOST LIKELY LOW-SCORING GAME

  • MoSSBODS & MoSHBODS : Western Bulldogs v Port Adelaide (151 to 152)
  • TAB : Fremantle v Hawthorn (154.5)
  • Centrebet : GWS v St Kilda (154.5)

MOST LIKELY HIGH-SCORING TEAM

  • All : Geelong (106 to 108)

MOST LIKELY LOW-SCORING TEAM

  • MoSSBODS & MoSHBODS : Western Bulldogs (66)
  • TAB & Centrebet : St Kilda (57.5 to 59)

MoSHBODS' performance was very good relative to naive forecasting in selecting the extremes of team and game scoring last weekend, attaching:

  • 7.1% probability to the highest-scoring team, Collingwood (against a naive forecast of 5.6% since 18 teams were playing)
  • 11.0% probability to the lowest-scoring team, Western Bulldogs (against a naive forecast of 5.6%)
  • 18.6% probability to the highest-scoring game, Geelong v Melbourne (against a naive forecast of 11.1% since 9 games were played)
  • 18.8% probability to the lowest-scoring game, Port Adelaide v GWS (against a naive forecast of 11.1% since 9 games were played)

This week, MoSHBODS has

  • six teams as more likely than 1 in 18 to be the highest-scoring: Geelong, Melbourne, GWS, Richmond, West Coast, and Gold Coast
  • seven teams as more likely than 1 in 18 to be the lowest-scoring: Western Bulldogs, Fremantle, St Kilda, Brisbane Lions, Collingwood, Carlton, and Sydney.
  • four games as more likely than 1 in 9 to be the highest-scoring: Crows v Dees, Cats v Lions, Roos v Eagles, and Giants v Saints.
  • three games as more likely than 1 in 9 to be the lowest-scoring: Dogs v Power, Dockers v Hawks, and Dons v Swans.

WAGERS

Investors have five wagers this week, two unders and three overs.

The relevant weather forecasts are as follows:

  • Richmond v Collingwood (MCG - unders bet): Mostly cloudy. 30% chance of rain.
  • GWS v St Kilda (Sydney Showground - overs bet): Shower or two. 50% chance of rain.
  • Gold Coast v Carlton (Carrara - overs bet): Mostly sunny. 20% chance of rain.
  • Adelaide v Melbourne (Adelaide Oval - overs bet): Shower or two increasing. 70% chance of rain.
  • Western Bulldogs v Port Adelaide (Ballarat - unders bet): Shower or two. 70% chance of rain.

So, not ideal, but not catastrophic, and we are still three or four days out from the relevant games.

Overlays range mostly from 1 to 2.5 goals, except in the Giants v Saints game where it's about four goals, though a bit less if we choose to adjust for the likelihood of rain.

(By the way, that $1.90 price in the Dogs v Power game isn't a typographical error. For some reason that one game was offering $1.90 prices at the time I went in. Won't matter a jot, of course, if it doesn't turn into a collect ...)

PERFORMANCE TO DATE

It rare for the MoS twins' results against the bookmakers to differ by much, but this week saw MoSSBODS finishing on the correct side of the TAB's and Centrebet's totals in only four of the nine games, while MoSHBODS did the same in seven. This despite the fact that the total forecasts of the twins were only between 3 and 5 points different in the three games where MoSHBODS was on the right side and MoSSBODS wasn't. Totals forecasting success, like all footy forecasting against a threshold, can sometimes be decided by a single kick.

That left MoSSBODS' with a season-long 48% record against the TAB and Centrebet, and left MoSHBODS with a 49% record against the TAB and a 52% record against Centrebet. 

MoSSBODS' landed 0 of 1 overs bets with the TAB, 0 of 1 unders bets with Centrebet, and 2 of 2 overs bets with Centrebet last weekend. That lifted its overall strike rate on overs bets to 32% and dropped its overall strike rate on unders bets to 60%.

On the mean absolute error (MAE) metric, MoSHBODS registered the lowest MAE for home team scores and totals, MoSSBODS registered the lowest MAE on away team scores, and the two bookmakers tied for lowest MAE on game margins.

Centrebet still leads on the season-long view for home team scores (narrowly, from MoSSBODS) and for game margins, but is now tied with the TAB for game margins. The TAB still leads on away team scores.