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.
Read MoreModelling Game Outcomes In-Running
/Way back in 2010 I developed a model to estimate the Home team's chances of victory in-running (ie during the course of a game) based on the lead it held at the time and the time remaining in the game. In a subsequent post I investigated ways of combining the in-running projections of that model with the TAB Bookmaker's pre-game assessments in something of a proto-Bayesian way.
Read MoreLeading 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.
Read MoreWhen 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.
Read MoreScoring 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.
Read MoreAre Some Games Harder to Predict Than Others?
/If you've ever had to enter tips for an office competition where the the sole objective was to predict the winner of each game, you'll intuitively recognise that the winners of some games are inherently harder to predict than others.
Read MoreThe Quality of the 2014 Finalists
/Based on end of home-and-away season MARS Ratings, as a group the 2014 Finalists are slightly inferior to their 2013 counterparts (though, oddly enough, the opposite would have been true had the Dons not been relegated to 9th).
Read MoreSuperMargin Implications? Yes, They Are Atrocious.
/In a recent blog I developed an empirical model of AFL scoring in which I assumed that the Scoring Shots generated by Home and Away teams could be modelled by a bivariate Negative Binomial and that the conversion of these shots into Goals could be modelled by Beta Binomials.
Read MoreWhy AFL Handicap-Adjusted Margins Are Normal : Part II
/In the previous blog on this topic I posited that the Scoring Shot production of a team could be modelled as a Poisson random variable with some predetermined mean, and that the conversion of these Scoring Shots into Goals could be modelled as a BetaBinomial with fixed conversion probability and theta (a spread parameter).
Read MoreWhy AFL Handicap-Adjusted Game Margins Are Normal
/This week, thanks to Amazon, who replaced my unreadable Kindle copy of David W Miller's Fitting Frequency Distributions: Philosophy and Practice with a dead-tree version that could easily be used as a weapon such is its heft (and assuming you had the strength to wield it), I've been reminded of the importance of motivating my distributional choices with a plausible narrative. It's not good enough, he contends, to find that, say, a Gamma Distribution fits your data set really well, you should be able to explain why it's an appropriate choice from first principles.
Read MoreRetrospective Review of Team Draws for 2014
/Seasons rarely pan out as you expect and team strengths wax and wane over the duration, so it's not entirely surprising that an assessment of the difficulty of a team's draw will differ in retrospect compared to an assessment made in prospect.
Read MoreThe 2014 Seasons We Might Have Had
/Each week the TAB Bookmaker forms opinions about the likely outcome of upcoming AFL matches and conveys those opinions to bettors in the form of market prices. If we assume that these opinions are unbiased reflections of the true likely outcomes, how might the competition ladder have differed from what we have now?
Read MoreSurrendered Leads
/Last weekend, thinking back over the season so far, I couldn't recall a game where a team had come from a long way behind in the final term.
Read MoreEntropy in AFL Scoring (Revisited)
/At the distinct risk of diving yet deeper into what was already a fairly esoteric topic, I'm going to return in this blog to the notion of entropy as it applies to VFL/AFL scoring, which I considered at some length in a previous blog. Consider yourself duly warned - this post is probably only for those of you who truly enjoyed that earlier blog.
Read MoreA Proposition Bet on the Score
/It's been a while since I've written about a proposition bet.
Read MoreHome Ground Advantage by Quarter
/MatterOfStats Founding Fellow, Greg, posed an interesting question to me last week: in which quarter is Home Ground Advantage (HGA) greatest?
Read MoreModelling the Total Score of an AFL Game
/Over the eight seasons from 2006 to 2013 an average AFL game produced about 185 points with a standard deviation of around 33 points. In about one quarter of the games the two teams between them could only muster about 165 points while in another one quarter they racked up 207 points or more.
Read MoreModelling Team Scores as Weibull Distributions : Part II
/In a previous post I discussed the possibility of modelling AFL team scores as Weibull distributions, finding that there was no compelling empirical or other reason to discount the idea and promising to conduct further analyses to more directly assess the Weibull distribution's suitability for the task.
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