Ensemble Encore

The idea of ensemble learning and prediction intrigues me, which, I suppose, is why I've written about it so often here on MoS, for example here in introducing the Really Simple Margin Predictorshere in a more theoretical context, and, much earlier, here about creating an ensemble from different Head-to-Head predictors. The basic concept, which is that a combination of forecasters can outperform any single one of them, seems plausible yet remarkable. By taking nothing more than what we already have - a set of forecasts - we're somehow able to conjure empirical evidence for the cliche that "none of us is better than all of us" (at least some of the time)

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AFL Crowds and Optimal Uncertainty

Fans the world over, the literature shows, like a little uncertainty in their sports. AFL fans are no different, as I recounted in a 2012 blog entitled Do Fans Really Want Close Games? in which I described regressions showing that crowds were larger at games where the level of expected surprisal or 'entropy' was higher.

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On Choosing Strong Classifiers for Predicting Line Betting Results

The themes in this blog have been bouncing around in my thoughts - in virtual and in unpublished blog form - for quite a while now. My formal qualifications are as an Econometrician but many of the models that I find myself using in MoS come from the more recent (though still surprisingly old) Machine Learning (ML) discipline, which I'd characterise as being more concerned with the predictive ability of a model than with its theoretical pedigree. (Breiman wrote a wonderful piece on this topic, entitled Statistical Modelling: The Two Cultures, back in 2005.)

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How Often Does The Best Team Win The Flag?

Finals series are a significant part of Australian sporting life. No professional team sport I know determines its ultimate victor - as does, say the English Premier League - on the basis of a first-past-the-post system. There's no doubt that a series of Finals adds interest, excitement and theatre (and revenue) to a season, but, in the case of VFL/AFL at least, how often does it result in the best team being awarded the Flag?

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VFL/AFL Home-and-Away Season Team Analysis

This year, Sydney collected its 8th Minor Premiership (including its record when playing as South Melbourne) drawing it level with Richmond in 7th place on the all-time list. That list is headed by Collingwood, whose 19 Minor Premierships have come from from the 118 seasons, one season more than Sydney/South Melbourne and 11 more than Richmond.  

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The 2014 Grand Final : When the Coin Flipped

The Sydney Swans were deserved pre-game favourites on Saturday according to most pundits (but not all - congratulations to Robert and Craig for tipping the winners). At some point during the course of their record-breaking loss that favouritism was handed to the Hawks. In this blog we'll investigate when.

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Grand Final History 1898-2013 : Winning Team Scoring Patterns

Only three teams in VFL/AFL history have trailed by more than three goals at Quarter Time in the Grand Final and gone on to win. The most recent was Sydney in 2012 who trailled the Hawks by 19 at the first break before rallying in the second term to kick 6.0 to 0.1, eventually going on to win by 10 points, and before that Essendon who in 1984 trailed the Hawks by 21 points at Quarter Time - and still trailed them by 23 points at Three Quarter Time - before recording a 24 point victory on the strength of a 9.6 to 2.1 points avalanche in the final term.

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Scoring Catenation: An Alternative Measure of Momentum

Almost two years ago, in a post-GF funk, I recall painstakingly cutting-and-pasting the scoring progression from the afltables site for 100 randomly-selected games from 2012. I used that data to search for evidence of in-game momentum, there characterising it as the tendency for a team that's just scored to be the team that's more likely to score next.

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Scoring Shot Conversion Rates: How Predictable Are They?

In my earlier posts on statistically modelling team scoring (see here and here) I treated Scoring Shot conversion as a phenomenon best represented by the Beta Binomial distribution and proceeded to empirically estimate the parameters for two such distributions, one to model the Home team conversion process and the other to model Away team conversion. The realised conversion rates for the Home team and for the Away team in any particular game were assumed to be random, independent draws from these two fixed distributions.

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Leading and Winning in AFL

One of the bets that's offered by TAB Sportsbet is on which of the teams will be the first to score 25 points. After analysing scoring event data for the period 2008 to 2014 provided by Paul from afltables.com I was surprised to discover that the first team to score 25 points goes on to win the game over 70% of the time.

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When Do AFL Teams Score?

Soccer goals, analysis suggests, are scored at different rates throughout the course of matches as teams tire and as, sometimes, one team is forced to press for a goal or chooses to concentrate on defending. Armed with the data provided by Paul from afltables.com, which includes every scoring and end-of-quarter event from every game played between the start of season 2008 and the end of the home-and-away season of 2014, we can investigate whether or not the same is true of AFL scoring.

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Scoring In Bursts: Evidence For In-Game Momentum?

The notion of momentum gets flung about in sports commentary as if it's some fundamental force, like gravity, that apparently acts at both long and short distances. Teams have - or don't have - momentum for periods as short as a few minutes, for perhaps half a quarter, going into the half-time break, entering the Finals, and sometimes even as they enter a new season, though I think when we start talking about momentum at the macro scale we wander perilously close to confusing it with another fundamental sporting force: form. It's a topic I've addressed, in its various forms, numerous times on MoS.

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