Matter of Stats

View Original

2011 Round 8 Results: Better Still

Do you recognise this set of numbers: +14, -24, -14, -3, +3, -32, +34, +12? It's the quarter-time margins for each of this round's winning teams which, as you can see, are negative for half of the winners and significantly negative for two of them.

The Roos belong to the -24 margin, having trailed Melbourne 3.2 to 7.2 at quarter time only to kick 16 more goals in the remainder of the game to Melbourne's 5, resulting in a win for them by 41 points. That cost Investors 0.3%. Hawthorn owns the -32, trailing 0.1 to 5.3 at quarter time before registering 14.14 to the Saints' 5.6 in the final three quarters to run out 30 point victors, thereby covering the 20.5 points spread and enriching Investors by 3.0%. 

Across the entire round, the Head-to-Head Fund bagged 3 from 3 and the Line Fund 3 from 6, enough to inject 6.5% back into Investor Portfolios restoring them to near perfect health. Investor Portfolios are now trading at 97.5c, up 11.5c over the last two rounds.

The Line Fund's 26 and 21 record juxtaposed with its 2.9% loss clearly demonstrates the distinction between prowess in picking line betting winners and in probabilistically assessing their chances. Still, Investors did profit this week from the Fund's 3 and 3 record, so it's legitimate to assess the most recent evidence about the Fund's probability assessments as positive.

As well, the Head-to-Head Fund is 8 and 2 for wagers in the last 3 rounds and has almost dragged itself back into profitability, so there's reason for hope there too.

On head-to-head tipping, ProPred recorded the week's lone perfect round, but this was enough only to lift it to within 4 tips of the leader, Bookie_9, on 43.5 from 61 (71%). Bookie_9, along with Home Sweet Home, recorded the round's second-best performances of 7 from 8. Follow the Streak meantime dropped nearer to the foot of the ladder in scoring the round's poorest performance of 3 from 8, some 2.5 tips below the all-tipster average for the round of about 5.5 from 8.

Eight tips now separate Bookie_9 in 1st place from Easily Impressed II in last.

Bookie_9 continues to head all Margin Predictors and is now 1.2 points per game ahead of Combo_7. Five tipsters retain sub-30 MAPEs - each of them now showing mild biases away from the Home team as has been the norm for the TAB Sportsbet bookmaker in seasons past - and five more are within half a point per game of this benchmark. 

Three Margin Predictors have line betting records significantly better than chance: Bookie_3 (61%), ProPred_3 (59%), and ProPred_7 (57%).

H2H, both in its adjusted and unadjusted forms, now leads the TAB Sportsbet bookmaker on probability scoring, an achievement that should not be lightly glossed over (though I'll now proceed to do just that). ProPred is only narrowly behind this bunch, justifying its description as a probability predictor, though the same cannot be said of WinPred, the alleged Winner Predictor, which has so far proven to be a poor probability, margin and head-to-head predictor.

The Line Fund's probability predictions are now virtually at a level equivalent to that which could have been achieved by chance. Woo hoo.