Reoptimisation and the Fear of Overfitting : ChiPS 2016
/Richard McElreath, in one of the lectures from his Statistical Rethinking course on YouTube aptly and amusingly notes that (and I'm paraphrasing) models are prone to get excited by exposure to data and one of our jobs as statistical modellers is to ensure that this excitability doesn't lead to problems such as overfitting.
Read MoreThe 2016 AFL Draw: Difficulty and Distortion
/The 2016 AFL Draw, released in late October, once again sees teams playing only 22 of the 34 games required for an all-plays-all, home-and-away competition. In determining which 12 games - 6 at home and 6 away - a given team will miss, the League has in the interests of what it calls "on-field equity" applied a 'weighted rule', which is a mechanism for reducing the average disparity in ability between opponents, using the final ladder positions of 2015 as the measure of that ability.
Read MoreClose Games in VFL/AFL History: Do Successful Teams Win Them?
/Recently, we've looked at the history of margins, of blowouts, mismatches and upsets, and the history of conversion rates. Today we'll be looking at the history of close games, which I'll define as games that are decided by a goal or less.
Read MoreScoring Shot Conversion in the VFL/AFL - Quantifying Team, Venue and Era Effects
/In the previous blog we reviewed the Conversion Rate history of the VFL/AFL competition looking, in turn, at how it has varied across eras for different venues and for different teams. That blog provides some useful context for this one and you might find it helpful to review it before proceeding.
Read MoreScoring Shot Conversion History in the VFL/AFL (1897-2015)
/The off-season always seems a good time for adopting a more sweeping historical perspective in the analyses here on MatterOfStats. Today we're going to be reviewing Scoring Shot Conversion rates across the 119 seasons of the VFL/AFL from both a venue and a team perspective.
Read MoreCompetitiveness in the VFL/AFL (1897-2015)
/It's been a while since we've reviewed the history of game margins and, in today's blog, we'll consider that history from a number of perspectives.
Read MoreUnexpectedly Large Victories in NRL: Parallels With AFL
/In the previous post we saw that large or what might be called "blowout" victories in AFL games occurred at a rate much higher than the rate at which bookmakers assigned equally large handicaps to those same games, and we saw why this might be the case from a theoretical perspective on the assumption that AFL game margins were Normally distributed.
Read MoreWhy There'll Always Be More Blowouts Than We Expect
/Last night I was thinking about the results we found in the previous blog post about upsets and mismatches and wondered if the historical pattern of expected game margins was borne out in the actual results. On analysing the data I found that there were a lot more victories of 10 Scoring Shots or more in magnitude than MoSSBODS had predicted. In most seasons, at least one-third of the games finished with a victory margin equivalent to 10 Scoring Shots or more, which was usually two or three times as many as MoSSBODS had predicted.
Read MoreWinning and Losing Streaks and Their Effects on Team Scoring
/The idea for this blog came in an e-mail from long-time Friend of MoS, Michael, who wondered if the absence of lengthy winning streaks by teams like Hawthorn in 2015 reflected some feature of the game of Australian Rules or of the AFL competition that rendered such streaks self-limiting in length.
Read MoreOn the Relative Importance of Offensive and Defensive Ability in VFL/AFL History
/In the previous post here I introduced MoSSBODS 2.0, a Team Rating System design to provide separate Offensive and Defensive Ratings for teams in the VFL/AFL. Today I want to explore the relationship between teams' Ratings and their on-field success.
Read MoreAn Improved VFL/AFL Team Rating System: MoSSBODS 2.0
/Earlier this year in this blog, I introduced the MoSSBODS Team Rating System, an ELO-style system that provides separate estimates of each team's offensive and defensive abilities, as well as a combined estimate formed from their sum. That blog post describes the main motivations for a MoSSBODS-like approach, which I'll not repeat here.
Read MoreGrand Final Leads - How Much Is Enough?
/Quick question: what proportion of teams that have led at the end of the 1st Quarter of a Grand Final have gone on to take the Flag? Supplementary question: how big does the Quarter-time lead need to be before the probability reaches 90%?
Read MoreInferring 2015 Grand Final Prices
/This time of year it's always fun to consider what the current wagering markets imply about the likely Grand Final prices.
Read MoreTeam-by-Team and Venue-by-Venue Conversion Rate History
/Today's post continues the recent theme of entries here in the Statistical Analysis part of the site, taking yet another look at Scoring Shot Conversion rates but this time on a team-by-team and venue-by-venue basis.
Read MoreConversion Rates in Finals versus Home-and-Away Games
/Subsequent to the previous post, which looked broadly at the differences in aggregate scoring metrics for Home-and-Away games compared to Finals from the same era, Friend of MoS, Liam, made a great suggestion for a follow up analysis.
Read MoreWhat's Different About Finals?
/Finals, by their nature, tend to pit more-evenly matched teams against one another, on average, than do games from the home-and-away season. It seems reasonable, therefore, to hypothesise that margins will tend to be smaller in Finals than in the home-and-away season, but what other changes in scoring behaviour might we expect to see?
Read MoreThe 2015 Finalists: A Quarter-by-Quarter Head-to-Head Analysis
/As the FootyMaths Institute has highlighted in its most recent post, this year sees a startlingly wide spread of winning rates amongst the eight Finalists when we consider only their games from the home-and-away seasons against one another.
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