2016 Round 17 : Overs/Unders Update

With the change to the methodology for predicting team and total scores as described in last week's blog, it appears we've entered a new phase of overs/unders wagering. For the first time in the Overs/Unders Fund's history, it's made more overs than unders wagers this week.

In total, there are three overs and two unders wagers, all of them in games where either the Line or Head-to-Head Fund has already wagered, meaning that three games remain wager-free this week. The five overs/unders wagers take the total at risk this weekend to just over 10% of the original Overall Portfolio, which is the highest proportion for a single round since Round 12.

In choosing the markets in which overs/unders bets could be made this week, I decided to continue to use the same minimum overlays that I've been using throughout the season so far, which are that:

  • For an unders bet, the offered Total needs to be 2 goals or more above MoSSBODS' projected total
  • For an overs bet, the offered Total needs to be 2 points or more below MoSSBODS' projected total

With the new methodology, the minimum overlay for an unders bet is probably now too high since MoSSBODS no longer systematically underestimates totals, but that's something I'll review in the off-season.


One way that MoSSBODS' reduced bias is evident this week is in a comparison of its projected totals with those being offered by the TAB. MoSSBODS' average expected total is 175 points and the TAB's is 177 points.

As well, only three of MoSSBODS' projected totals differ from the TAB's in absolute terms by more than two goals, and five are within a goal. At a team level, MoSSBODS has 7 teams scoring more than does the TAB, and 11 scoring fewer, but for only three teams is the absolute difference more than 2 goals.

MoSSBODS has the Lions v Giants game as the high-scoring matchup of the round, while the TAB has it as one of two joint-highest scoring clashes (the other being the Crows v Pies game), and MoSSBODS has the Blues v Eagles game as the round's lowest scoring contest while the TAB has it as the Dockers v Cats game.

Comparing the performances of MoSSBODS and the TAB over the season to date we have:

Home Team Scores

  • MoSSBODS : MAE 20.3 / Ave Error +8 (Actual - Predicted)
  • TAB : MAE 19.4 / Ave Error +3

Away Team Scores

  • MoSSBODS : MAE 19.4 / Ave Error +2
  • TAB : MAE 19.6 / Ave Error (4)

Total Scores

  • MoSSBODS : MAE 26.8 / Ave Error +10
  • TAB : MAE 24.8 / Ave Error (1)


  • MoSSBODS : MAE 29.4 / Ave Error +6
  • TAB : MAE 28.8 / Ave Error +7

If my analysis of the new total and team score projection methodology holds up, we should expect to see improvements in MoSSBODS' performance relative to the TAB in these areas.