Matter of Stats

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2014 - Round 20 : Decently Diversified

This week the Head-to-Head Fund has made a larger number of bets than it has in any single round all year, but the average size of those bets and the fact that the Line Fund has made just five wagers and the Margin Fund only six, has meant that less of the Recommended Portfolio is at risk this week than in any round since Round 11.

Most of the Head-to-Head wagers are quite small - two of them are for under 1% of the Fund - so the total amount risked across the six wagers is only 16.5% of the Fund. The largest single wager is the one on Port Adelaide to defeat Sydney at $2.90 and the sole wager on a certifiable longshot is for just 0.6% of the Fund on GWS to defeat Essendon at $6.

Four of the five Line bets are on teams receiving start, which is what history tells us that Investors should prefer, and we've no Chasms of Despair. All-in-all then, a satisfying bundle of reasonable opportunities and manageable threats.

Port Adelaide bears a disproportionate share of Investor dreams this week and, as is often the case, a disproportionate share of their fears as well. The difference between a favourable and unfavourable result in Port's game represents 8% of the Portfolio, from a high of +4.8% if they win to a low of -3.2% if they lose by 16 points or more.

The Brisbane Lions, Geelong and GWS are the only other teams carrying more than 2% upsides, while the Lions and the Eagles are the only other teams carrying downsides of that same magnitude or higher.

A best-case round this week would lift the Recommended Portfolio by a bit over 17c while a worst-case round would drop it by just over 12c.

TIPS AND PREDICTIONS

Disagreement amongst the Head-to-Head Tipsters is at unprecedently high levels this week, five contests yielding minority tipping blocks comprising nine or more Tipsters.The Port Adelaide v Sydney game has generated the highest level of disagreement, the final Tipster split coming in at 15-13 in favour of the Bookmaker Favourite Swans.

Other games with large minorities are Richmond v Essendon (11-17), Carlton v Gold Coast (18-10), Brisbane Lions v Adelaide (10-18) and West Coast v Collingwood (19-9).

Easily Impressed I is responsible for the week's highest Disagreement Index (51%), though Home Sweet Home (49%), Short Term Memory I (46%) and Easily Impressed II (42%) are all also impressively contrarian. There is, I guess, a limit to the number of contrarian Tipsters you can have in any set of them because the phenomenon is by its nature self-limiting: there's only one way of being contrarian in any single game and only nine opportunities to exercise that go-it-alone spirit in any round.

The Margin Predictors have demonstrated far lower levels of disagreement, producing margin predictions on either side of zero in only five games and doing so with any convincing vigour in just two - Port Adelaide v Sydney and West Coast v Collingwood - where at least more than a handful have faced-off on the other side of the zero point.

Additional evidence for the Predictors' general lethargy with respect to dissidence is the fact that in all but one game the range of margin predictions spans less than six goals, the exception being the Hawthorn v Melbourne game where ProPred's +14 is set against RSMP_Simple's +68.

Combo_NN_1 has the round's highest Mean Absolute Deviation (MAD) from the all-Predictor average, partly a consequence of its being Extreme Predictor in five games. The next-highest MAD belongs to Bookie_3, which is Extreme Predictor for two contests, followed by C_Marg, which is also Extreme in two. Win_7, though Extreme Predictor in three games, is only ranked fourth on MAD.

Six of the nine contests see the Head-to-Head Probability Predictors unanimous in their opinions of the likely winners, while in the Tigers v Dons clash they're split 7-1 to the Dons, in the Eagles v Pies clash they're split 6-2 to the Eagles, and in the Power v Swans clash they're tied up at 4-4. Probability ranges are, for the most part, small, coming in at 25% points or less in every contest except St Kilda v Western Bulldogs, where C_Prob's longstanding affection for the Saints has seen it rate them as 47% prospects, some 20% points higher than any other Predictor.

Win_Pred, which is Extreme Predictor in four games, has the highest MAD amongst the Head-to-Head Probability Predictors, ahead of C_Marg, which is Extreme in just three games. Bookie-RE, though Extreme Predictor for five games, has only the fifth-highest MAD.

Five teams are assessed by the Line Fund algorithm as better than 65% chances on line betting this week: Western Bulldogs (75%), Port Adelaide and Melbourne (both 68%), and Brisbane Lions and West Coast (both 67%). So sharp are the algorithm's assessments this week that if we allowed the Line Fund to wager on away teams too, it would have wagered in all nine contests.

ChiPS, meantime, has recommended a wager on five teams, the largest of them on the Saints at $4 and the next-largest on the Tigers at $2.60.

Eight of its nine margin predictions carry the same sign as the difference in team Ratings, the Eagles v Pies game the odd one out as the Pies' 11 Rating Point superiority is more than offset by the positive effects on the Eagles' chances of Form Difference (+2), HGA (+13), and Interstate Status (+6).