Numbers game: Which AFL teams should rise and fall in 2018?

Ryan Buckland Columnist

By Ryan Buckland, Ryan Buckland is a Roar Expert


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    The numbers game is back, despite one of the all time stinkers of a prediction flowing from our analysis this time last year. But don’t fret, because the guidance provided is a useful place to start our preseason proper.

    For those who are new to this, this column looks at some of the numbers available for crunching and simply crunches them.

    The facts below are presented without fear or favour, with minimal spin and maximum substance. There are some tricky concepts; please refer to the first run of this column in this form from 2016.

    Housekeeping done, the miss was Richmond. The 2017 numbers game reckoned the Tigers were due for some further regression last year, given Richmond outperformed its Pythagorean win total by 2.2 wins. The Tigers finished 2016 on eight wins, and the formula said that was incredibly flattering: Richmond should have won 5.8 games.

    Fortunately, I have been in this game a little while now, and cunningly planted an A-grade hedge around that Skunk Cabbage of a prediction:

    The Tigers fell from 15 wins to eight last season, with some combination of poor strategy, lousy execution and lack of talent conspiring to wreck their season. I suspect the former two are more important than the latter, meaning Richmond and their coaching group have a chance to turn it around.

    Indeed. Let this serve as a reminder that the below analysis is fallible. Taken with the right dose of levity it is a useful guide to the season ahead.

    For example, last year’s numbers game was not kind to Hawthorn; the club promptly put up its worst win total since 2009. It also liked the Adelaide Crows, and did not like the Carlton Blues. It gave pause for thought regarding St Kilda, and was shouting about Port Adelaide’s potential for improvement when no one else would listen. Given that strike rate, it may pay to look a little closer at what we’re dredging up this year.

    Pythagorean wins
    The Big Mac of the numbers game, Pythagorean wins is a concept applied to sporting leagues the world over. It seeks to contextualise how a team performed over the course of a year, using points for and against. The formula determines whether the club earned more or less wins than it should have if there was no 22 game season, and wins were instead doled out based on a team’s strength over the year.

    It’s useful to weed out teams which significantly over performed or under performed their capabilities. Last year, the formula said Richmond outperformed their win total by 2.2 wins, which is generally a mark of regression. By contrast, Adelaide underperformed by close to two wins, and although the club’s win total went backwards it finished first on the ladder.

    Last year’s Pythagorean table was skewed by the Essendon saga – its final insult – given the return of the Dons was the mother of all out-of-model events. Essendon’s Pythagorean total from 2016 was 2.8, or 0.2 fewer wins than it collected; Essendon won 13 games last year. Given that, the system performed quite well.

    What do the tea leaves say this year?

    Wins Pythag Wins Difference (+/-)
    Adelaide 15.5 17.6 -2.1
    Brisbane Lions 5.0 4.4 0.6
    Carlton 6.0 5.6 0.4
    Collingwood 9.5 10.7 -1.2
    Essendon 13.0 12.5 0.5
    Fremantle 8.0 4.7 3.3
    Geelong 15.5 14.7 0.8
    Gold Coast 6.0 4.9 1.1
    Greater Western Sydney 15.0 14.2 0.8
    Hawthorn 10.5 8.6 1.9
    Melbourne 12.0 12.2 -0.2
    North Melbourne 6.0 7.7 -1.7
    Port Adelaide 14.0 16.6 -2.6
    Richmond 15.0 14.8 0.2
    StKilda 11.0 10.2 0.8
    Sydney 14.0 16.2 -2.2
    WCE 12.0 12.3 -0.3
    Western Bulldogs 11.0 10.2 0.8

    Adelaide underperformed its Pythagorean win total for the second year in a row, garnering 15.5 wins against expectations of 17.6 wins. That level of outperformance would suggest all things being equal the Crows will be thereabouts the top four once again, and should challenge for the minor premiership.

    The two other significant underperformers were Port Adelaide (-2.6 wins) and Sydney (-2.2 wins). Both can be explained quite rationally.

    For the Power, their penchant for smacking the weaklings of the competition around meant the club accrued a bunch of excess margin in those games versus the rest of the league. That pumps up their season-long points for (and puts downward pressure on points against), leading to more Pythagorean wins.

    By contrast, Sydney’s underperformance can be explained by its slow start: from Round 1 to 6, the Swans earned 2.2 Pythagorean wins but had no real life wins, where from Round 7 to the end of the year the club earned 14 Pythagorean wins, which was bang on its total.

    Other underperformers included the mid-table Collingwood (-1.2 wins) and lower-table North Melbourne (-1.7 wins). The latter is particularly intriguing given there is a building consensus that the ‘Roos will finish in the bottom four once again in 2018.

    At the other end of the spectrum, Fremantle absolutely obliterated its Pythagorean win total by 3.3 wins – the Dockers were the Adelaide of losing. According to the formula Fremantle’s performances were worth 4.7 wins, the second-lowest total in the league, where the club managed eight victories. This can be partially explained by Fremantle’s penchant for both close games (seven games decided by less than two goals) and blow outs (five games decided by more than the average margin plus one standard deviation – 56 points last year). All things being equal that would signal regression.

    The only other significant outperformer was Hawthorn, which garnered 10.5 wins against expectations of 8.6 wins. There’s an element of Fremantle about this one – seven close games, three blow outs – but that doesn’t explain the whole lot. The Hawks simply outperformed, and on this analysis may find it hard to hold ground in 2018.

    Jack Gunston Hawthorn Hawks AFL 2017 tall

    Close games
    One explanation for a team under or outperforming its Pythagorean total is its performance in close games. Winning a bunch of close games – defined as a final margin of 12 points or less – will tend to result in a team outperforming its underlying potential, and vice versa.

    That’s because close games are shown to be a coin flip over the long run. Few teams can continuously win games decided by two straight kicks. The one exception in recent times has been Geelong, which is currently sitting 10-2-1 in games with a margin of 12 points or less since the start of the 2015 season. The rest of the competition is 114-8-123 – which is to say basically a 50-50 proposition.

    Geelong went through the full 2017 season without losing a close game – the closest the club came a draw against the Greater Western Sydney Giants in Round 15. As a result, the Cats won 2.5 games more than you would generally expect a team to win given how their season played out.

    Close Wins Close Games Difference (on 50-50)
    Adelaide 1.5 3.0 0.0
    Brisbane Lions 2.0 2.0 1.0
    Carlton 3.0 6.0 0.0
    Collingwood 2.5 6.0 -0.5
    Essendon 1.0 3.0 -0.5
    Fremantle 4.0 7.0 0.5
    Geelong 5.5 6.0 2.5
    Gold Coast 1.0 3.0 -0.5
    Greater Western Sydney 6.0 8.0 2.0
    Hawthorn 4.5 7.0 1.0
    Melbourne 3.0 6.0 0.0
    North Melbourne 1.0 6.0 -2.0
    Port Adelaide 1.0 3.0 -0.5
    Richmond 1.0 5.0 -1.5
    StKilda 2.0 3.0 0.5
    Sydney 3.0 6.0 0.0
    WCE 3.0 9.0 -1.5
    Western Bulldogs 3.0 7.0 -0.5

    That Geelong has outperformed the maths for so long could suggest an even bigger crash in close games is coming. Equally, what’s to say there isn’t some kind of close game secret sauce Chris Scott has his players drinking?

    The other team that had positive ledger in close games in 2017 was GWS. The Giants played eight games with tight margins, winning five and drawing two others. That yields six wins from eight tries, or an excess of two, suggesting a decline is in prospect. However, an unknown variable with the new kids is injury luck, and the role the club’s lack of it played in its 2017 campaign.

    On the other side of the coin sit North Melbourne (one win from six close games), Richmond (one win from five), and West Coast (three from nine). The Roos had a close game deficit of two games, while the Tigers and Eagles were 1.5 games in the red. If that snaps back in 2018, we would expect the trio to get a boost to their respective win totals relative to their underlying performances.

    Liam Duggan West Coast Eagles AFL 2017 tall

    Blow outs
    The inverse of the close game is the blow out: games with a margin equal to the average margin plus one standard deviation. Setting it this way means the top 15 to 20 per cent of games are considered blow out results, depending on the exact distribution of scoring.

    Last season, a margin had to reach 57 points to constitute a blow out result, down from 67 points in 2016 and 66 points in 2015. 34 games met that threshold; if the points threshold from 2016 had applied there would have been just 23 games push into blow out territory. It was a fairly tight season after all.

    Blow outs are an important metric, because all things being equal, putting up margin is a solid indicator of a team’s ability, but a win is a win no matter the margin. So, a team that registers a lot of blow-out wins is probably better than its win total, and a team that registers blow out losses is probably worse. You can generally pick the team that finished on top in both categories if you think about it for a few seconds.

    Blown Out Blow Out
    Adelaide 1 8
    Brisbane Lions 5 2
    Carlton 3 0
    Collingwood 0 0
    Essendon 1 3
    Fremantle 5 0
    Geelong 0 3
    Gold Coast 6 1
    Greater Western Sydney 0 2
    Hawthorn 3 0
    Melbourne 0 1
    North Melbourne 1 1
    Port Adelaide 2 6
    Richmond 2 1
    StKilda 2 2
    Sydney 0 3
    WCE 1 1
    Western Bulldogs 2 0

    Adelaide led the way in blow-out wins, racking up a quite stunning eight of the things in 2017. What’s more impressive is they recorded three of those blow outs against their peers in the top eight – the rest of the competition did it four times (Essendon twice, North Melbourne once, and St Kilda once – go figure).

    The other team to drop the hammer in its wins was Port Adelaide, blowing out six opponents (albeit none of them top-eight opponents). Essendon, Geelong and Sydney did it three times. The Dons are the interesting case here; the club’s flair for fast counter attacking football overwhelming West Coast, Port Adelaide and St Kilda throughout the year. Theirs is an interesting platform to build on starting this season.

    Going the other way, Gold Coast (six), Brisbane (five) and Fremantle (five) were the whipping boys of the competition. The Lions attempted to square the ledger, blowing out the Dockers and Suns for two of their five victories. Here’s a little titbit: two of Brisbane’s other three victories were in close games, while their final win came with a score that was just under the average of the season (30 points).

    Finally, Collingwood had no blow out losses, but also couldn’t manage a blow out win. It’s quite a rare feat: the last team to do that was the Western Bulldogs in 2016, while no club did it in 2015. One of these teams won a premiership while straddling the margin line, and the other did not.

    Alex Fasolo Collingwood Magpies AFL

    Fixture change
    Finally, we can look briefly at whether any teams are expected to see a significant ramp up or down in their respective fixture difficulty. We do this by taking the average Pythagorean win percentage of a team’s opponents, rather than wins and losses, for reasons we’ve discussed above.

    This is a useful guide, but as it’s based solely on last season’s results it is not rock solid. By way of example, here is what each team’s 2017 fixture projected like last preseason versus how it actually turned out.

    2017 (Projected) 2017 (Actual) Projected Rank Actual Rank
    Adelaide 49.1% 50.6% 12 8
    Brisbane Lions 48.7% 52.2% 15 4
    Carlton 48.4% 52.3% 16 3
    Collingwood 50.8% 52.0% 6 6
    Essendon 48.7% 47.2% 14 17
    Fremantle 51.3% 52.7% 5 1
    Geelong 50.6% 49.4% 7 11
    Gold Coast 49.5% 48.8% 11 13
    Greater Western Sydney 52.3% 52.1% 1 5
    Hawthorn 52.3% 52.4% 2 2
    Melbourne 50.2% 49.1% 8 12
    North Melbourne 47.5% 48.0% 18 14
    Port Adelaide 49.0% 47.8% 13 15
    Richmond 48.1% 45.9% 17 18
    StKilda 52.0% 51.8% 3 7
    Sydney 50.0% 47.6% 9 16
    WCE 49.6% 49.9% 10 10
    Western Bulldogs 52.0% 50.1% 4 9

    Most clubs stay within reasonable distance of their preseason estimates, but others don’t. For instance, Carlton was projected to have the third least difficult fixture – it became the third most difficult once the results rolled in.

    Here’s how 2018 is looking now, compared to how last year played out.

    2017 (Actual) 2018 (Projected) Change
    Adelaide 50.6% 50.4% -0.5%
    Brisbane Lions 52.2% 49.5% -5.1%
    Carlton 52.3% 49.7% -4.9%
    Collingwood 52.0% 47.4% -9.0%
    Essendon 47.2% 49.8% 5.4%
    Fremantle 52.7% 51.9% -1.7%
    Geelong 49.4% 49.6% 0.4%
    Gold Coast 48.8% 49.1% 0.7%
    Greater Western Sydney 52.1% 50.5% -3.0%
    Hawthorn 52.4% 51.1% -2.4%
    Melbourne 49.1% 50.3% 2.4%
    North Melbourne 48.0% 48.8% 1.6%
    Port Adelaide 47.8% 49.3% 3.2%
    Richmond 45.9% 51.4% 11.9%
    StKilda 51.8% 50.7% -2.3%
    Sydney 47.6% 49.4% 3.8%
    WCE 49.9% 51.2% 2.5%
    Western Bulldogs 50.1% 50.0% -0.2%

    Most clubs bounce around about the same mark – everyone has to play everyone else at least once so this is ultimately a function of the double up opponents. Richmond’s fixture difficult ramps up significantly though, from the least difficult to the second most difficult, a fate which befalls most premiers.

    Essendon has also seen its fixture difficult ramp up, but from a low base (17th to 10th). West Coast begin a new era with a tricky fixture, albeit one that’s not hugely more challenging than their 2017 slate turned out to be.

    Fremantle has somehow once again been lumped with the most difficult fixture in the league, after their fifth ranked fixture evolved into the most difficult in 2017. That is likely a result of the Pythagorean wins formula rating Collingwood, Essendon and Port Adelaide higher than their respective win totals would suggest.

    At the other end of the spectrum, Collingwood has been granted a kind slate of games, and the least difficult fixture in the competition. The Pies face an average opponent with a Pythagorean win total of 47.4 per cent, almost 1.5 points weaker than 17th ranked North Melbourne.

    So… what?
    That’s a lot of numbers. It’s difficult to draw definitive conclusions based on this alone – if it was easy my work for the year would be done – but we can glean some insights. Here is each team’s results from each of the four categories, and an assessment of whether it suggests good, bad or neutral news for the team in 2018.

    AFL preseason prediction graphic

    Adelaide, Collingwood and North Melbourne have a net two positive indicators heading into the year, suggesting they could improve their respective win totals. By contrast, Fremantle, Gold Coast and Hawthorn each have a net two negative indicators. They could be the candidates for regression.

    But then, Richmond showed universal regression signs last year, and won the whole thing.

    Now the scene is set, let’s dig a little deeper and see if we can’t find this year’s brightest prospects.

    Ryan Buckland
    Ryan Buckland

    As an economist, Ryan seeks to fix the world's economic troubles one graph at a time. As a sports fan, he's always looking one or two layers beneath the surface to search for meaning, on and off the field. You can follow Ryan here.

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    The Crowd Says (65)

    • Roar Rookie

      January 17th 2018 @ 7:44am
      Jakarta Fan said | January 17th 2018 @ 7:44am | ! Report

      Well presented Ryan. Not everyone likes maths and statistics, but your info is fascinating. Based on the pythag predictions of the 2017 Ladder, it actually was very very close and did give as good an indication as many of the wild speculative predictions based on emotion and guesswork:



      (1) Adelaide 17.6 (1)
      (2) P. Adelaide 16.6 (5)
      (3) Sydney 16.2 (6)
      (4) Richmond 14.8 (3)
      (5) Geelong 14.7 (2)
      (6) GWS 14.2 (4)
      (7) Essendon 12.5 (7)
      (8) WCE 12.3 (8)
      (9) Melbourne 12.2 (9)
      (10) Collingwood 10.7 (13)
      (11) W. Bulldogs 10.2 (10)
      (12) St. Kilda 10.2 (11)
      (13) Hawthorn 8.6 (12)
      (14) N. Melbourne 7.7 (15)
      (15) Carlton 5.6 (16)
      (16) Gold Coast 4.9 (17)
      (17) Fremantle 4.7 (14)
      (18) Brisbane 4.4 (18)

      So it sets the stage for an interesting assessment of your 2018 pythag predictions.

      Watching with interest!!!

      • January 17th 2018 @ 11:21am
        Larry1950 said | January 17th 2018 @ 11:21am | ! Report

        I know they’re just numbers but any prediction that has the Lions 2 spots behind the Suns & last on the ladder obviously doesn’t have a youth improvement factor built in while there seems to be a recruitment improvement factor if Port are assessed as second on the ladder.
        I’ll wait on the inevitable ‘form’ fluctuations because this is another one of those “better teams on paper” assessments which has made the NSW league origin team favourites in most series over the last 12 years.

        • Roar Rookie

          January 18th 2018 @ 10:10pm
          Jakarta Fan said | January 18th 2018 @ 10:10pm | ! Report

          Larry1950, the above ladder etc was the actual ladder for 2017 with the actual 2017 pythag predictions, not for this next season. 2018 is still a mystery and that’s why I’m waiting to see Ryan’s 2018 pythag predictions as I think that may be a better indicator as a basis for making our own 2018 predictions, which of course will factor in the recruitment success or otherwise, returnees from injury, aging of senior players etc.

    • January 17th 2018 @ 7:54am
      Neil from Warrandyte said | January 17th 2018 @ 7:54am | ! Report

      I’m really looking forward to seeing how the tigers perform this season given that they haven’t started a season as reigning premiers in the AFL era.
      They have struggled with their mental demons that were born from many years of an expectation that they would always eventually fail, no matter the effort. Now they’ve won the ultimate prize, can they now finally play with a freedom that will elevate them to sustained greatness or regress back to the pack with a mood of complacency?

      • Roar Guru

        January 17th 2018 @ 12:55pm
        Dalgety Carrington said | January 17th 2018 @ 12:55pm | ! Report

        Reigning premiers contend with a whole bunch of factors that make the defence year much more of a battle.

        They instantly are more examined and their systems picked apart by most coaching groups, so not only are their strengths adopted and possibly nullified by others, more weaknesses are exposed, plus any surprise factor they had goes.

        They also become a more prized scalp for other playing groups and they’re playing more primed opponents week in week out. Their draw is theoretically harder, not always the case as the season pans out.

        And of course, as you point out, there is the greater potential for complacency and just run-of-the-mill drop off that occurs, especially if there’s a reasonable percentage of first or second-year players from the premiership squad.

      • Roar Guru

        January 17th 2018 @ 1:03pm
        Paul D said | January 17th 2018 @ 1:03pm | ! Report

        Personally I couldn’t give a stuff how the Tigers players approach this season – I’m far more interested in seeing how the Tigers fans approach this season.

        I remember Cam Rose (seem to be quoting him a bit atm) saying something along the lines of “I can only hope all fans suffer as I have suffered” in response to one of my Brisbane-is-really-stuffed articles – well, I’ll happily suffer the way he did in 2017

        That bloody great cross they’ve been lugging around and moaning to all and sundry about how heavy it is has finally been put down, and I think they’re going to find it very weird at times this season, without their customary excuse to fall back on.

        • January 17th 2018 @ 1:15pm
          Macca said | January 17th 2018 @ 1:15pm | ! Report

          PaulD – They will revert to type on the first Friday of the season if the blues manage to pull off an upset in round 1.

          I think Richmond fans are Nietzsche devotees and see happiness as a dull waste of human life.

    • Roar Guru

      January 17th 2018 @ 8:08am
      Cat said | January 17th 2018 @ 8:08am | ! Report

      Great article Ryan, you may want to have the editors swap around your blown out and close games tables, they don’t line up with the text regarding each (ie: when you talk about close games it is the blown out games table and vice versa).

      • January 17th 2018 @ 9:19am
        Macca said | January 17th 2018 @ 9:19am | ! Report

        Also the blues seem to have won 6 of 3 close games

        • Roar Guru

          January 17th 2018 @ 10:23am
          Cat said | January 17th 2018 @ 10:23am | ! Report

          Upon closer examination that entire table doesn’t make sense to me. WCE played 3.0 close games but had 9.0 close wins for –1.5

          • January 17th 2018 @ 10:50am
            Macca said | January 17th 2018 @ 10:50am | ! Report

            The difference is from 50/50 – 9 close games at 50/50 should have been 4.5 but they won just 3 which leads to the -1.5.

            • Roar Guru

              January 17th 2018 @ 11:13am
              Cat said | January 17th 2018 @ 11:13am | ! Report

              It makes sense now that the columns are labelled properly 😉

    • January 17th 2018 @ 8:31am
      Brendon the 1st said | January 17th 2018 @ 8:31am | ! Report

      Nice article as usual Ryan.

      Would it be possible to somehow work the champion data player stat’s into this? They’ve recently released their list profiles for the teams and rank teams first to last in Talent, I believe Sydney now has the most talented list by the numbers.

      Maybe this could be factored in with your system?

      Looking at their list and yours I have it as a race between Port, Sydney and Adelaide.

      • Roar Guru

        January 17th 2018 @ 8:43am
        Cat said | January 17th 2018 @ 8:43am | ! Report

        Where are these lists located?

      • Roar Guru

        January 17th 2018 @ 10:25am
        Paul D said | January 17th 2018 @ 10:25am | ! Report

        Ryan has a long running grip with Champion Data and unavailability of stats #freethestats

        Not sure he’s going to be able to do that unless someone springs for a Champion Data subscription

      • Roar Guru

        January 19th 2018 @ 8:18am
        Redb said | January 19th 2018 @ 8:18am | ! Report

        I think Adelaide are busted, Might make the Top 4 but mentally the team is gorn. New coach, new A list players required.

    • January 17th 2018 @ 9:24am
      Macca said | January 17th 2018 @ 9:24am | ! Report

      Interesting that the blues ended up having the third hardest draw last year – yet still managed to reduce their blowouts, score more and win just less game while playing a significantly younger team.

      There was more improvement than a simple look at the ladder would suggest.

    • January 17th 2018 @ 9:44am
      Sam said | January 17th 2018 @ 9:44am | ! Report

      Hi Ryan,

      In the Pythagorean win table you have Adeliade on 14.5 wins. Pretty sure that should read 15.5, as they did finish top of the table…