Matter of Stats

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2013 : Round 22 - Results

A very wayward Carlton, in going down to Essendon 9.22 to 12.10 on Saturday became only the 3rd team in the last decade to lose a game despite kicking as many or more behinds as their opponent had scoring shots. 

The previous instance was in Round 5 of 2012 when Fremantle's 7.15 lost to, coincidentally enough, Carlton's 10.5 but, before that you need to go all the way back to Round 17 of 2004 to find another instance when West Coast's 9.22 wasn't enough to defeat Port Adelaide's 16.6. In total, there have only been 10 such games since the start of the 1980 season.

The Blues' inaccuracy erased any hope of their covering the 18.5 point spread that Investors were facing and produced one of the two line betting losses of the weekend. Other losses came in the form of two of the three Head-to-Head Fund wagers, and 13 of the 14 Margin Fund wagers. Totalled, these losses outweighed the gains by an amount equal to 1.4% of the Fund, leaving the Recommended Portfolio up now by just 7c on the season.

All three Funds nonetheless remain in profit, though the Line Fund only barely, its half a cent loss this week leaving it up by just 3.5c on the season.

TIPSTERS AND PREDICTORS

Eight favourites were victorious this week, though with most of the best-performed Head-to-Head Tipsters opting for the non-resulting upset in the Saints v Suns game, scores of 7 from 9 predominated. That left Combo_NN2 as MAFL's leading Head-to-Head Tipster, still one tip ahead of a pursuing bunch of 10 Tipsters.

The Tigers' 121-point win over the inaptly named Giants and the slightly bigger-than-expected win by Freo over Port Adelaide both served to drive mean absolute prediction errors (MAPEs) up this week, but results in other games were close enough to pre-game expectations to permit all but four Margin Predictors to record sub-30 MAPEs. In Combo_7's case, it was the fourth consecutive round in which it had achieved that level of performance and elevated it into 3rd position on the MAFL Ladder, relegating Bookie_LPSO into 4th. The two RSMP Predictors retain the two top spots, RSMP_Weighted now having opened up a 75-point lead over RSMP_Simple, which all but assures it of victory for season 2013.

Unusually, there's currently a confluence of MAPE and line betting performances, with the four Margin Predictors responsible for the best season-long MAPEs the only ones also to have recorded positive ROIs on line betting across the season.

The Margin Predictors' SuperMargin performances were, on the whole, unimpressive this week, with Bookie_Actual (which uses the line market handicap to inform its bucket selections), RSMP_Weighted and Combo_7 best amongst them, each choosing the correct bucket in two games.

ProPred_3 managed just a single correct selection this week but still leads all-comers in terms of overall accuracy across the season. WinPred_7, which also had one correct prediction, remains in 2nd, just one correct selection behind ProPred_3 and one correct selection ahead of Combo_NN2.

Four Predictors now have positive ROIs for the season, the three just mentioned plus WinPred_3.

(Earlier today I posted a blog on the Statistical Analyses journal that highlights the challenges in successfully wagering in the SuperMargin market.)

With so many favourites winning, the Head-to-Head Probability Predictors enjoyed strongly positive probability scores for the round. Bookie_LPSO had the round's best score, just a fraction better than Bookie_RE's. There was no change in the ordering of these Predictors this week.

The Line Fund algorithm, which benefits not at all from the predominance of victories by favourites (or of any other team type, come to that), had its worst single round probability score since Round 15.