Five new AFL metrics, and the players who lead them in 2017

One of the more annoying aspects of being a die hard fan of Australian rules football is the deplorable state of access to information and statistics on player and team performance relative to many other global sports.

The AFL has regulated a monopoly on the collection and dissemination of AFL statistics in a company of which it is the majority owner. Said company provides access to statistics to clubs and media partners, but does not provide access to statistics to the general public. We as the ultimate consumers of the AFL, who finance the league and the means for collection of these statistics, sometimes get to peer behind the curtain if a journalist happens to write something about someone that has some numbers in it.

It’s a topic I could spend 4,000 words discussing and debating, and which others have penned very compelling pieces in recent times. That’s for another time, because who wants to read a rant about such matters.

We do get some of the good oil, in the form of basic box score-type statistics: kicks, handballs, marks, contested possessions and the like. Some of the more advanced stuff is available through the AFL Live App, but it is difficult to analyse because of the form it comes in. It grants us some insights – indeed, I use a lot of it in my own writing, as do many others – but it’s like making a plain cheese pizza. There’s a ton of stuff sitting right there to enrich our basic understanding of the game and what happens on the field.

That’s not to say we can’t get creative. We can combine some of the box score numbers we receive easily, add a sprinkling of some of the more advanced numbers we can access through the AFL Live app, and develop some new and – I hope – interesting numbers.

The sky is the limit on this. We could come up with all sorts of whacky combinations (divide scoring shots by running bounces! Add frees for, frees against and divide by disposals!) but that would be stupid. Instead, the five metrics I’ve come up with below are realistic, and should provide some insights into how the players who’ve ranked high or low in them have performed this year.

One ground rule before we begin: players need to have played 15 games or more to qualify for a ranking. Two thirds of a season seems to be the cut off for perceived All Australian eligibility, so let’s roll with it here. All of the numbers are on a per game basis. Otherwise, let’s go.

Giveaway Rate

What it is: Clangers less free kicks against, divided by disposals
What it shows: how “clean” a player’s disposal is
What’s the average: 8.8% of disposals

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This season’s leader in Giveaway Rate (GR) is Jack Macrae, who has a GR of just 4.5%. Macrae has been one of the few Bulldogs to enhance his reputation this season, on account of the quality of his disposal and his work rate around the ground. Melbourne’s Cam Pederson has a better rate (3.9%), but just misses the qualification threshold for now. Should he play against Collingwood this weekend, Pederson has a chance to take the lead.

Rounding out the top five are: Wayne Milera (5.2%), Shannon Hurn (5.4%), Clayton Oliver (5.4%) and Matt Rosa (5.6%). The five worst players on GR were: Dale Thomas (14.1%), Jayden Hunt (13.6%), David Mackay (13.6%), Will Langford (13.5%) and Sam Gilbert (13.5%). Those are some interesting names.

Around the Ground Work

What it is: My “groundball” metric standardised to the mean plus uncontested marks standardised to the mean, with a cap of 2 on the standardised score (I’ll explain this don’t worry…)
What it shows: by combining the number of times a player has won a loose or ground ball with the number of uncontested marks, I think it shows how hard a player works across the ground
What’s the average: Groundballs: 4.7 | Uncontested marks: 3.5

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This one is a bit more complicated. What I’ve done here is standardised how a player performs on each of the metrics using a Z-score, with an upper and lower bound of a Z-score of “2” for each metric. This is so a player who scores very high on one metric but low on another (Gary Ablett, who is high on groundballs but low on uncontested marks; Jeremy Howe who is low on groundballs but high on uncontested marks) doesn’t beat out a more balanced scorer – we want to see which player scores high in both categories.

My groundball metric is an attempt to get as close to the official definition of a groundball get as possible. It takes contested possessions, and strips out free kicks won and contested marks, which count as contested possessions. The residual is equal to looseball gets, hardball gets and contested knock ons.

Now that the boring stuff is out of the way…

Mitch Duncan is the number one on Around the Ground Workrate (ATGW) in 2017, with a score of +3.44. Duncan doesn’t get the kudos he deserves on account of playing as the third man behind the Dangerfield-Selwood combo, but this stat highlights his contribution to Geelong’s midfield really well. He’s a link man, the glue that holds the two ends of the ground together.

The remainder of the top five are: Marc Murphy (+3.34), Tom Mitchell (+3.25), Tom Rockliff (+3.18) and Elliot Yeo (+3.13). Those at the bottom are key forwards, defenders and ruckmen: Nathan Brown (-2.56), Nathan Vardy (-2.52), Eric Hipwood (-2.34), Billy Longer (-2.29) and Will Hayward (-1.96). C’mon Will, the other guys are big oafs. What’s your excuse?

Tackle Rate

What it is: Tackles divided by disposals
What it shows: The extent to which the activities of a player are more defensively-oriented when they are around the ball
What’s the average: 0.174 (or one tackle laid for every 5.7 disposals)

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The leader here is surely obvious: GWS’s Shane Mumford, who has a Tackle Rate (TR) of 0.52, or one tackle laid for every 1.93 disposals. He’s so far ahead of the competition it’s not funny: second place Tom Liberatore has a TR of 0.4 (one tackle for every 2.49 disposals), and third place Jack Steele is on 0.36 (2.75).

Geelong’s Scott Selwood would have, perhaps appropriately, smashed the lot of them if he’d met the criteria of games played. Selwood has a TR of 0.63 in season 2017, meaning he lays a tackle for every 1.6 disposals. That’s almost four times the competition average.

Coming in fourth and fifth place are Andrew Swallow (0.36) and Jake Barrett (0.35). At the other end of the spectrum are Michael Hurley (0.04, or one tackle for every 24 disposals), Michael Hibberd (0.05, 1:20.4), Jake Lloyd (0.05, 1:19.6), Kaiden Brand (0.63, 1:16), and James Sicily (0.07, 1:14.5). The renowned seagulls of the competition aren’t too far behind: Andrew Gaff, Daniel Rich, Rory Laid, Heath Shaw and Zach Tuohy round out the top ten.

Metres Gained per Disposal

What it is: Metres gained divided by disposals (duh)
What it shows: How many metres a player gains on an average disposal
What’s the average: Of the top 130 players for metres gained, 16.2

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Unfortunately, this is one of the titbits that I can only partially access. A website which I won’t name for fear that the AFL will come with their scythe and chop it down published the top 100 players for total metres gained and average metres gained on the season, which I’ve pulled and have used here.

In first place is Nathan Wilson, with a Metres Gained per Disposal (MGPD) of 28.7, not too far ahead of Gold Coast’s Trent McKenzie (27.1) and Sydney’s Lance Franklin (25.6) in second and third. Jayden Short and Jayden Hunt round out the top five, with 24.5 MGPD respectively.

At the other end of the spectrum are the volume shooters; the guys who don’t gain a lot of territory but who’ve muscled their way onto the list of total metres gained for the season because they’ve had so many disposals. Hawthorn’s Tom Mitchell is the poster boy, with just shy of 36 disposals per game, but a MGPD of 8.8 – less than a third of GWS’ Wilson. Other volume shooters include Adelaide’s Matt Crouch (10.6 MGPD), Nat Fyfe (11.7 MGPD) and Adam Treloar (11.8).

Score Facilitation Score

What it is: Total score involvements per game that were not goals, behinds or direct goal assists
What it shows: Which players help create scoring opportunities further up the ground
What’s the average: 3.98

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This is another one where we’re restricted to the top of the pops only due to frustrating, unjustifiable data limitations. I only have data for the top 130 players on score involvements, so in reality the guys sitting at the top are going to be significantly higher than the average.

Who is the AFL’s leading point guard? Adelaide’s Matt Crouch*, who has a Score Facilitation Score (SFS) of 6.23 per game. That means he is involved in 6.23 scores per game that aren’t him directly scoring or goals directly created from an assist – what an assist actually is I’m not too sure because there’s no definition published.

Other leading AFL point guards are Brendon Goddard (6.14), Luke Dahlhaus (5.86), Taylor Adams (5.76) and Scott Pendlebury (5.75).

One guy that sticks out down the other end of the table is Sydney’s Lance Franklin. Despite leading the competition in score involvements, the vast majority of these (68% in fact) are Franklin hitting the scoreboard himself. His SFS is 2.9, surely in the top half of the league but well off what a raw analysis of his score involvement tally might suggest.

So there we go, five new AFL statistics derived mostly from publicly available information. Given we could have a bit of fun with what are ostensibly basic accounting statistics, just imagine what we could do if we were graciously permitted access to the secret sauce held behind lock and key.

*Apologies to Matt Crouch – this was the only image Getty Images, the Official Provider of Photographic Content to and every other sports blog too low rent to shell out a grand for the rights to photos, had available.