MAFL 2010 : Round 6 Results

Regression to the mean is a bit like unprompted advice from a friend: not always welcome.

But a weekend of regression it ultimately was for Investors with the Recommended Portfolio, as their last-chance Eagles failed to capitalise on their early-game form and eventually went down to the Dockers by over six goals.

With MIN#002 losing also, the only Investor to show a profit on the weekend was MIN#017 who made a 0.55% gain.

Here are the details for all Investors:

Overall, Investors with the Recommended Portfolio profited from four games and made losses in the other four. The most disappointing loss, I felt, was the one on the Dogs, who looked set to take the competition points before a scrappy final term in which they kicked 0.2 to the Saints' 3.4 saw them fall just 3 points short.

Geelong, mercifully, fully justified their $1.01 price by obliterating the Tigers at Kardinia. So comprehensive was their victory, in fact, that they broke the scoring worm on the www.afl.com.au site:

(Apart from the Cats' escaping worm-orbit in that screen capture above, there's also something going on with the axis scaling, which seems to suggest that the Cats are in front by more than 150 points when their lead is actually 'only' 108. I think this is an example of what programmers would refer to as an 'edge case', basically a rare but pernicious eventuality that a programmer must recognise and code for.)

Here are the full details of the weekend's wagering:

On tipping, just five favourites were victorious, leaving a little room for other tipsters to outperform BKB, which Short Term Memory I, Silhouette and Consult The Ladder duly did in each bagging six.

That leaves Short Term Memory I in the outright lead on 35 (73%), and four tipsters - Silhouette, Consult The Ladder, Easily Impressed I and Follow The Streak - just one tip behind on 34 (71%).

It's a bizarre season indeed when members of the Easily Impressed and Short Term Memory heuristic families are vying for tipping supremacy.

Chi continues to deliver the sort of tipping performances that leave me glad that I retired the Chi Fund.

This week the Heuristic Fund dropped 2.2%, so Shadow is now just two further weeks of losses away from losing control of this Fund which, as things currently stand, would be handed over to Short Term Memory I. That'd be fun - having our money entrusted to an algorithm that is the statistical equivalent of a goldfish.

On MARS ratings, Geelong did enough, and the Saints didn't do quite enough, such that positions 1 and 2 have been reversed, with the Cats taking a 1.6 rating point lead. The only other changes were amongst the teams in the bottom third of the ratings ladder, the most dramatic of which were the Dons' rise from 15th to 12th, and the Dees' fall from 11th to 14th.

On margin predicting, BKB is now the only margin-tipper with a sub-30 mean APE, and is one of only two margin-tippers - HAMP being the other - to have a sub-30 median APE.

Consequently, BKB leads on both mean and median APE, with LAMP second on mean MAPE and HAMP second on median APE.

At this point in the season I'll confess to being surprised at the strong performances of HAMP and LAMP but, each being based solely on bookie prices, I guess they should be doing reasonably well given the even stronger performance of BKB.

I'm far less surprised with the performance of HELP, which managed just three correct line tips this weekend and essentially stood still in terms of the three probability score metrics. Richmond's failure to win on line betting despite a ten-goal start was particularly damaging to HELP's probability scores as it had attached an 80% probability to Richmond's preventing such an embarrassment.

The Eagles' poor showing in the final term that doomed many Investors to an unprofitable weekend was their sixth losing final term of the season. They now have an appalling 44.3 percentage in final terms but, amazingly, this is only the second-worst performance in the competition, eclipsed by the Crows' 40.7 percentage.

Only two teams now have a term that they've failed to lose all season. They are the Swans and the Dogs, who've each won all six of their second terms.

MAFL 2010 : Round 6

It's as if someone flicked a switch, which in a fashion someone did.

All six Funds have taken up their option to participate in the weekend's wagering, many of them with an alacrity that can only be exhibited by something inanimate that has no sense of the terror that can be induced by a large wager on a team at $1.01.

Hope is the only Fund to show any restraint, chancing just a single wager - its first for the season - of around 1.6% on Sydney at $1.55 facing the Lions at the SCG. New Heritage has waded in like an adrenalin junkie coming home from an enforced 6-week stay at a Buddhist retreat. It's found 6 wagers to its liking, these totalling almost 41% of the Fund and including a 13.5% tilt at the Cats paying $1.01, an almost equally futile 0.1% wager on the Pies at $1.55, and a 3.1% bet on the Crows at $2.35.

The ELO-Line Fund has been almost as profligate, dropping 30% on 6 wagers (one of which - 5% on the Roos - I've yet to make as the market isn't currently available). Mercifully, it's avoided taking the Cats giving 60.5 (yes, over 10 goals) start to the Tigers.

Prudence, Shadow (and hence the Heuristic-Based Fund) have all outlayed about 15% of their respective Funds, in Prudence's case on four wagers, and in Shadow's and the Heuristic-Based Fund's, on three.

Here's the detail (in a slightly larger font this week):

Unsurprisingly, this cacophany of wagers puts a considerable chunk of total Funds in play this weekend, including those of MIN#002 and MIN#017, whose money is at risk for the first time this season. Welcome.

For those with the Recommended Portfolio, the Sydney v Brisbane game represents the largest gap between exaltation and despair, the difference being almost 7.5% of total Funds. The Geelong v Richmond game is next largest, but in that game the upside doesn't justify the label "exaltation" and the downside is the poster-child for "despair".

The remaining details of what result mean what profit and loss are in the Ready Reckoner, which appears below:

As it's been a while since you've had to worry about not just which team wins but also by how much they win, I'll just briefly go through how the Ready Reckoner works.

Consider the second row of the Recommended Portfolio part. It shows that if the Roos win, Investors' net MAFL worth increases by 1.64% (in this case the head-to-head and the line bets win).

If, instead the Roos lose head-to-head but Port fails to cover the spread, then the figure in the third column, representing the case where the home team (the Roos) win head-to-head but lose on handicap, pertains. It shows that Investors will lose 0.90% in that instance, the result of the head-to-head bets losing but the handicap bet winning.

The final column shows the result if the Roos lose head-to-head and also lose on handicap. In that case Investors will be down 1.8% for the game.

Next we look at the tipsters, who this week agree more often than not about the likely outcomes of each contest.

• The Dogs are 13-2 favourites over the Saints, Consult The Ladder and Silhouette being the only holdouts.
• Melbourne are 11-4 favourites over the Roos, though 3 of the 5 margin-tippers are on the Roos. All of the margin predictions are for a victory by either side of 9 points or fewer and this is one of BKB's two Games of the Round.
• Port Adelaide are 11-4 favourites over the Crows, and again 3 of the 5 margin-tippers are on the less-favoured team. Both BKB and LAMP have this game as one of their two Games of the Round.
• Hawthorn are 10-5 favourites over the Dons. Yet again the margin-tippers are split 3-2 in favour of the less-favoured team. ELO predicts that the Dons will win by just a point and therefore has this as its Game of the Round.
• Sydney are unanimous favourites over the Lions. Predicted margins range from 12.5 points to 17 points, so no tipster is foreseeing a blowout.
• Geelong are unanimous favourites over the Tigers. In this game, though, a blowout is seen as a distinct possibility. The bookies are giving the Tigers 60.5 start, which is one of the largest starts amongst my records. The only larger start was the 75.5 points that the Cats gave the Dees in Round 3 of 2008 (which, by the way, the Dees covered easily, going down by just 30 points).
• Collingwood are 11-4 favourites over the Blues. Once again the margin-tippers are 3-2 to the underdogs. Chi has the Blues winning by just 4 points and so has this as his Game of the Round. LAMP has the Pies winning by 1 point and has this as its second Game of the Round.
• Fremantle are 12-3 favourites over the Eagles. HAMP tips the Eagles to win by 1 point and has this as its Game of the Round.

The plethora of Games of the Round is a reflection of the overall narrowness of expected victory margins. Apart from the all-feline Cats v Tigers matchup where the Cats seem destined for a percentage-building massacre, no line market is offering a start greater than 15.5 points. That should make for a cardiovascularly taxing weekend.

Finally, to the HELP predictions.

HELP's predictions this week are just a little more risky than last week's. Two of the predictions are only barely non-naive - the first two - and five more have associated probabilities ranging from 58% to 63%. Only the 80% prediction for the Tigers to lose by less than 60.5 points will have any significant effect on HELP's average probability scores.

MAFL 2010 : Round 5 Results

That was a weekend that could easily the unwary into thinking there's something in this statistical modelling stuff.

Six wins from seven bets, with two of the wins coming from seriously unfancied teams, lifted the Heuristic Fund by almost 30% and left it up almost 41% on the season. Investors with the Recommended Portfolio are now, therefore, up over 4% on the season.

The only bet we lost was the one on the Hawks, who just couldn't quite do enough and went down by two straight goals to the Roos. In the only game in which we didn't have a starter, Port Adelaide, who were $3.75 shots mid-week and who were playing at home and so fair-game for the Heuristic Fund or the Hope Fund, outlasted the Saints at Footy Park.

But I'll take what we landed and just smile at what we might have missed.

Here are the details of the weekend's wagering:

Home Sweet Home and Short Term Memory I recorded the weekend's best tipping performances, each bagging 7 from 8, and five other tipsters, the Heuristic Fund's current guardian, Shadow, among them, scored 6.

That leaves three tipsters as joint-leaders of our tipping competition, Easily Impressed I, Short Term Memory I and Follow The Streak, all on 29 from 40 (72.5%). With only four favourites collection the competition points this round, BKB had another mediocre return and now sits two tips off the pace on 27 from 40.

Short Term Memory I now leads the race to be the next guardian of the Heuristic Fund, though with Shadow winning again this week it'll be at least Round 9 before that can happen.

With Round 6 upon us, Shadow will start trading as a Fund in its own right next weekend, as will New Heritage, Prudence and the ELO-Line Funds. So, Investors with the Recommended Portfolio will be doubly exposed to Shadow's prowess for the next 3 rounds at least - once via the Heuristic Fund and again via the Shadow Fund.

On MARS ratings, losses by St Kilda and Geelong cost both teams ratings points but left them in positions 1 and 2, albeit with a smaller lead over the pursuing duo of the Pies and the Dogs. Sydney and Carlton both pushed up a ranking spot, overtaking a plummeting Brisbane in the process.

Fremantle round out the top eight, and have now almost a 5-point lead over the ninth-placed Hawks. Melbourne are the weekend's biggest improvers. They leapt four spots into eleventh, a just reward for their 50-point victory over the Lions.

Margin prediction proved hazardous again this weekend. HAMP produced the round's best MAPE (32.4), a fraction ahead of ELO (33.3) and Chi (33.5). BKB, in a rare show of weakness, came last amongst our margin-tipsters with a MAPE of 35.6.

However, across the entire 5 rounds, BKB still leads both on mean and median APE. HAMP is now 2nd on both measures, with LAMP is 3rd on median APE and ELO 3rd on mean APE.

HELP scored marginally better than a naive tipster this week, correctly selecting 5 of the 8 line winners to take its aggregate record to 21-19, and accruing probability scores a fraction higher than would have been accrued by a tipster assigning a 50% probability to every tip.

Its season-long performance is still sub-naive.

This week the 16 teams combined to register as many goals as they did behinds, 187 of each, which makes the season's conversion rate now just 50.3%. This is, as those of you who've read my three earlier blogs on Modelling AFL Scoring (Part I, Part II, and Part III will know, significantly below the long-term average of 53.64%.

Adelaide and Essendon are doing most to drag the average conversion rate down. The Crows have kicked 41.59 to be at 41%, and the Dons 54.67 to be at 44.6%. St Kilda, with 70.40 (63.6%), and the Swans, with 78.64 (54.9%), are doing most to raise the level.

Round 6 is next, and that's when all the Funds are in play.

MAFL 2010 : Round 5

Well I did expect the level of wagering activity to ratchet up this weekend compared to last, but I thought Hope would be contributing to at least some of that increase.

That's not the case though. Hope has reviewed the market offerings and decided to return to slumber for at least another week; Shadow has looked at the same market and taken out its metaphorical knife and fork, rediscovering its Round 3-style appetite for the punt.

While Hope has passed on all eight contests, Shadow has plunged on the home team in seven, rating only Port Adelaide as home team no-hopers for the weekend. Here's the detail:

So, for the first time this season - possibly ever - Investors find themselves with an interest in the outcome of games across four consecutive days. Shadow's wagers across these four days traverse the landscape from a why-bother bet on Fremantle at $1.03 facing Richmond to a why-the-heck bet on Carlton at $4.60 taking on the Cats.

In between there are four more bets at should-win prices ranging from $1.10 to $1.28, and one more at an probably-won't-win price of $3.75. If you're looking for words to characterise the weekend's portfolio of wagers then, "diverse", "interesting" and "bold" would be among the more positive, while "motley", "perplexing" and "unfathomable" would be among the less favourable and, arguably, more accurate.

With level-stake betting, which is the Heuristic Fund's wagering strategy of record, return and risk correlate directly with market price, so Investors' fortunes are largely in the hands of the high-priced Dees and Blues this weekend. Here are the Ready Reckoner details:

Again this week with the bakers' half-dozen wagers, Investors might find a graphic a helpful way to understand what's required to return a profit.

Some conclusions that I draw from this graphic are that:

• If Melbourne and Carlton win, a profit is assured
• If neither Melbourne nor Carlton win, a profit is impossible
• If Melbourne doesn't win on Saturday, a profit requires at least one win on Sunday and on Monday. On Sunday, a Collingwood or a Hawthorn win will be sufficient if Sydney's won on Saturday and the Dogs have lost on Friday, and a Fremantle win will be sufficient if both the Dogs and Sydney have won in their respective clashes.
• If we've no winners at the end of Saturday, only Collingwood, Hawthorn and Carlton wins can save us.

Next a look at our tipsters, which shows that we've an unusually high level of agreement this round.

• The Dogs are unanimous favourites in their contest with the Crows on Friday. Margin predictions range from 17 to 41.5 points.
• Sydney are unanimous favourites taking on the Eagles, and in this game margin predictions range from 22 to 35 points, again foreshadowing a fairly substantial victory margin.
• Melbourne are 8-7 favourites over the Lions in yet another game that sees the margin tipsters on one team, in this base Brisbane, and the non-margin tipsters on the other, the only exception being Consult The Ladder who's also tipping the Lions.
• St Kilda are 14-1 favourites over Port Adelaide, despite Port's home ground advantage, a fact that has been deemed sufficient to warrant tipping Port only be Home Sweet Home. HAMP tips St Kilda to win by just 5 points and LAMP tip them to win by 'just' 23 points, which makes this game HAMP's and LAMP's Game of the Round (to the extent that it makes sense to label a game you're predicting as a four-goal win to the favourites as sufficiently close to justify the GoTR designation).
• Collingwood are unanimous favourites over the Dons, with tipped margins for the Pies ranging from 18 to 28 points.
• Hawthorn are 13-2 favourites over the Roos. Only Easily Impressed I and Short-Term Memory I are on the Roos. Predictions of Hawthorn's victory margin start at 15 points and run as high as 26 points, with BKB's prediction of a 21.5-point victory making this its Game of the Round - again only meaningful if you consider a 3-and-a-half-goal victory as "close".
• Fremantle are unanimous favourites over Richmond. Predicted victory margins run from a low of 23 points to a high of 48.5 points. This game, which is being played at Subi, could get very ugly for the Tigers, and a sporting declaration at three-quarter or even half time by the Dockers, should not be discounted.
• Geelong are 9-6 favourites over the Blues. Three of the five margin tipsters, all of which have selected the Cats to win, have done so by 7 points or fewer. That makes this game Chi's and ELO's Game of the Round. The remaining margin tipsters - LAMP and BKB - predict much more comfortable wins by the Cats of the order of 4.5 goals or so.

The high levels of agreement in this week's tips mean that there'll be little opportunity for significant changes to our tipster rankings by weekend's end. For example, the two leading tipsters - Consult The Ladder and Follow The Streak - differ only on one tip. It's for the Melbourne v Brisbane game, and Follow The Streak's on Melbourne, while Consult The Ladder's on the Lions.

Lastly, let's have a look at HELP's line betting tips for the week.

HELP has again been very conservative this week. No prediction has been made with an associated probability greater than 58%, which means that even the most disastrous round imaginable won't do too much damage to HELP's various probability scores. It also means that a perfect round won't repair much of previous weeks' damage either. Such is the price of timidity, the virtue of which can only be determined with certainty in retrospect.

MAFL 2010 : Round 4 Results

What a pleasant weekend's wagering that was.

On Saturday, Collingwood looked comfortable from the off and eventually annihilated the Hawks by 64 points, and then on Sunday St Kilda teased us long enough to let us feel that we earned our payoff having trailed by a point at quarter time, drawn level by half-time, led by a point at three-quarter time before running out 15-point winners. Two bets, two wins, the Heuristic Fund up another 4.3%, and the Recommended Portfolio now up 1.13% on the season. All of this with the prospect of the Hope Fund commencing trading in the coming round.

Here are the details of the weekend's wagering:

Favourites seemed to collectively recall their job descriptions this weekend, winning in all six games where one existed. In the two games with equal favourites the victors were the teams higher on the ladder, so BKB wound up tipping the card this week. Chi, Follow The Streak, and Consult The Ladder were the next-best tipsters, all bagging 7 for the round.

Those performances put Follow The Streak atop our tipster ladder on 25 from 32 (78%) and place Consult The Ladder in second on 24 from 32 (75%).

Though Investors have much to smile about courtesy of Shadow's tipping, they might have been happier still had the Heuristic Fund been originally entrusted to Follow The Streak, Consult The Ladder, Ride Your Luck or Easily Impressed I. Few investment strategies though are immune from post hoc regret.

On MARS ratings, St Kilda did enough in beating Freo to retain top spot, though the Cats' thumping of Port allowed them to narrow the gap between them and the Saints to just half a point. Collingwood's win and the Dogs' loss saw them swap places in third and fourth. The only other change in the top eight was Fremantle's elevation into it, due not to any improvement in Freo's rating but instead to the large rating declines suffered by Hawthorn and Adelaide, which simultaneously pushed them out of the top 8 and drove their rankings below the 1,000 mark.

Only seven teams remain with a rating above 1,000.

Margin prediction was a perilous occupation this week, as five games finished with victory margins of 40 points or more.

BKB emerged from the weekend with elevated mean and median APEs but still retaining the lowest mean APE and second-lowest median APE. ELO now has low median APE on its own and LAMP, finally being faithful to its name, now has the second-lowest mean APE.

Chi, despite being on the right team in seven of the eight games, had conservative margin predictions and, as a consequence, grievously insulted his mean and median APEs.

HELP's results were hard to distinguish from those of a notional naive tipster this week. It now has a 50% line tipping record for the season and overall sub-naive figures on all three probability scores.

This week I thought I'd finish with a look at what in previous seasons I've referred to as Alternative Premierships. In the table below I've shown the quarter-by-quarter performance of each team so far in season 2010.

St Kilda has performed well in quarters 1, 3 and 4, but has struggled a little in second quarters, winning two, losing two, and recording a sub-100 percentage, making it only the 10th-best team in this quarter.

Melbourne have struggled in the first quarter where they rank 11th, but have been positively diabolical in the second quarter, losing all four and scoring less than one point to their opponents' three. They've come to life in the second-half, however, producing performances that see them ranked 4th on their third-quarters and 1st on their final terms, where they're the only teams yet to lose a final term.

The Dogs have a different cadence to their performances: poor in the 1st and 3rd terms for which they're ranked 13th and 12th respectively, better in the 2nd and 4th terms where they're ranked 1st and 8th respectively. In 2nd terms they've outscored their opponents by almost two to one.

Fremantle's cadence matches the Dogs'. Freo ranks 10th and 13th for quarters 1 and 3, and 5th and 2nd for quarters 2 and 4.

Onto Round 5 then, where Hope begins ...