The Weekend Preview is a blog that aims to provide a different angle on the narrative of an upcoming sporting event.

AFL Round 23: Geelong vs. GWS Giants

AFL Round 23: Geelong vs. GWS Giants

Saturday Night, 26th August 2017 at Simonds Stadium

----------

Geelong is a unique and ideal place to play footy.

Steve Johnson [1]

----------

This weekend, Stevie J will make one last trip to his old home at Simonds Stadium (aka Kardinia Park) before he retires at the end of the 2017 season. Or will it be? One of the two possible permutations of a Geelong victory this weekend is a re-match with GWS at the same ground in Week 1 of the Finals. A Top-2 finish and the home ground advantage that this would give is quite the incentive for the Cats this weekend. A loss and they will be flying to either Sydney or Adelaide in the first week of the Finals. But, it is the other permutation from a victory for the Cats on Saturday Night that is even more intriguing. If the Tigers have a big win against the Saints and usurp the Giants into third spot on the ladder, they would set up a blockbuster Qualifying Final against the Cats. But where would this Final be played? The AFL are likely to choose the MCG in this scenario, and as a result suddenly Geelong’s home final looks more like an away final. Geelong will surely at least challenge (but fail) this AFL decision as they have recent evidence of the benefits of playing Richmond at home.

Only two weeks ago in Round 21, the Tigers went down by 14-points to the Cats at Simonds Stadium, and Hardwick bemoaned the home advantage the Cats received that day [2]:

The home crowd gets behind them. Have a look at the free-kick count.

Indeed, Geelong won the free kick count 28-17. Did this concern Hardwick? [2]

It is what it is. What I will say is you've got a significant home ground advantage. I understand what Chris [Scott] is saying, I'd be playing as many home games here as I can. It is tough to play.

They're an outstanding side, but they're an outstanding side plus when it comes to playing here.

It’s a long held belief that crowd support not only gives that boost to the home side playing performance, but also impacts on when the whistle will be blown. But, Hardwick acknowledged it happens everywhere: [2]

Absolutely. Our Tiger fans are the same when we get back home. It's the lie of the land.

That home for which Hardwick refers to is the MCG, and how the Tigers would love to play a Qualifying Final there. Is that fair on Geelong though? They are a Victorian team, but not a Melbourne team. So surely they should have the right to play at their home ground. The AFL would be loathe to have such a blockbuster game be played anywhere but the MCG, with maximising the crowd (or maximising profits depending on your level of cynicism) likely to guide their decision making.

So how much would the Cats be disadvantaged by the move to the MCG? Or rather how much benefit will the Cats get from playing at their true home at Simonds Stadium? Figure-1 and Figure-2 present Geelong’s record at Kardinia Park since the start of 2007: 73 wins from 82 games, which translates to a winning percentage of 89%. Remarkable.  And in those 82 games, how many times did the Cats win the free kick count? They won the free-kick count on 56 occasions or 68.9% of the time. Given the large sample size it appears quite convincing that the Cats have benefited from the rub of the green with the umpires when playing in Geelong. But there is also the argument that the Cats have prided themselves as being a strong contested ball team that get their hands on the ball first and as a result are more likely to earn a greater number of free kicks. But does winning the free kick count really make that much of a difference? There is occasionally a contentious decision at a crucial point in a game, but over the length of a game does the aggregate total of free kicks really make a significant difference?

 Figure-1: Geelong Results at Kardinia Park (Simonds Stadium) 2007-2017

Figure-1: Geelong Results at Kardinia Park (Simonds Stadium) 2007-2017

 Figure-2: Geelong record at Kardinia Park since the start of 2007 (82 games)

Figure-2: Geelong record at Kardinia Park since the start of 2007 (82 games)

Figure-3 presents Geelong’s free-kick differential from the first 22 rounds of 2017, with games played at Simonds Stadium highlighted. Geelong have won the free-kick count in 4 of their 6 games played at Simonds Stadium (66.7%), which is on a par with their long-term results. However, there is no obvious trend between winning the free kick count and match margin (if anything the trend is negative). As a point of comparison, Figure-4 presents West Coast’s free kick differential in 2017, with games played at Domain Stadium against interstate opposition highlighted. West Coast have a reputation of getting the benefit of the umpire when playing at home and their free kick trends are consistent with Geelong. They have won the free kick count on 6 of 9 occasions (66.7%), but with no overall discernible trend between winning the free kick count and the match margin.

 Figure-3: Geelong Free-Kick Differentials in 2017

Figure-3: Geelong Free-Kick Differentials in 2017

 Figure-4: West Coast Free-Kick Differentials in 2017

Figure-4: West Coast Free-Kick Differentials in 2017

So debunking the myth that home ground free kicks win you home games, why are Geelong so good at home? On the face of it, their 89% winning rate over 11 years is undeniable, and their 2017 form has been no different (5 wins from 6 games, 83% winning rate). But in truth, despite the 5 wins, their form at home this year has been patchy; with their loss to Sydney was terribly disappointing (with the absent Dangerfield providing further evidence that Geelong are too over reliant on their superstar player) and their narrow wins against both Port Adelaide and Fremantle could easily have gone the other way. Geelong’s most dominant performances have occurred elsewhere, but this should probably not come as too much of a surprise, as 4 of the 6 games they have played at Simonds Stadium were against fellow Top-6 opposition, with the odd one out, GWS, their opposition this week.

But there is one statistic that the Cats have won in each of their 6 home games this year, the Inside 50 count. Figure-5 presents Geelong’s Inside 50 differential from the first 22 rounds of 2017, with games played at Simonds Stadium highlighted. This ability to create more chances in their forward 50 than their opposition is a demonstration of not only their ball winning ability, but potentially their ability to play the ground better than their opposition (Simonds Stadium is the AFL's narrowest ground). In addition to this, in all but one of those games, Geelong have been able to restrict the opposition to a Goals per Inside 50 percentage of less than 25%, as presented in Figure-6. The one outlier? The 46-point loss to Sydney, when they allowed Sydney to score a goal from 34% of their Inside 50s. Geelong’s efficiency in that game? A 17% Goals per Inside 50 percentage, i.e. half the efficiency of Sydney.

 Figure-5: Geelong Inside 50 Differentials in 2017

Figure-5: Geelong Inside 50 Differentials in 2017

 Figure-6: Geelong Goals per Inside 50 conceded in 2017

Figure-6: Geelong Goals per Inside 50 conceded in 2017

Which brings us to the match this week. The Cats and the Giants played out an enthralling draw earlier this year with a Tom Hawkins point after the siren levelling the scores. The Cats will be happy to be back on their home turf for the re-match, but GWS have been growing stronger by the week as they regain players from injury. The one big question mark still hanging over the Giants is their ability to beat quality opposition away from home. The highest ranked team the Giants have beaten away from home this year remains the 9th placed West Coast, but the match against the Bulldogs in Round 21 seemed to dispel a lot of the naysayers. In that 48-point mauling of the Dogs, the Giants lost the Inside 50 count by 21, but were ruthlessly efficient going forward (47% GPI50) and miserly in defence (11% GPI50). Sound familiar? This could very well be a repeat of the Sydney game, with Geelong's reliance on creating more inside 50s than their opposition potentially not enough this week. It may just become a statement game for GWS heading into Finals. And then there is also Stevie J, who will be keen to have one more memorable night at the Cattery.

GWS to win by 23 points

----------

Post Match Comments:

Final Score: Geelong 15.13.103, GWS 8.11.59

Counter to expectation the Cats lost the inside 50 differential but won the match comfortably by 44 points. Geelong were simply too good and they maintain their strong record at home, whilst GWS continues to struggle to beat strong opposition away from home.

----------

[1] Collins, B., Eddy, B. (2016). “Champions: Conversations with Great Players & Coaches of Australian Football”. Slattery Media Group, Victoria, Australia.

[2] “’Look at the free-kick count’: Hardwick unhappy”, Dinny Navaratnam, afl.com.au, 12th August 2017:
http://www.afl.com.au/news/2017-08-12/look-at-the-free-kick-count-hardwick-unhappy

AFL Finals Preview Special

AFL Finals Preview Special

AFL Round 22: Carlton vs. Hawthorn

AFL Round 22: Carlton vs. Hawthorn