Sunday, June 24, 2018

AFL Power Rankings: Round 14 2018

The AFL tries to give the weaker teams the easier fixtures, and the stronger teams more difficult match-ups. However, teams rise and fall – who has got lucky in 2018 from their fixture becoming easier than expected?

Whenever the AFL fixture for the new season is released there are several ratings of the difficulty of each team’s fixture, including on this blog. Less often do you see the ratings revisited though, once we find out how strong each team is in this season, rather than how strong they were last season.

How the fixture was meant to work in 2018

In a season where each of the 18 AFL teams plays 22 matches, each team can only play five others twice. The AFL attempts to make the fixture more equitable by applying a ‘weighted rule’ to these ‘double match-ups’. Basically the 18 teams are divided into three groups of six based on how they finished after finals in 2017. Teams will tend to have more ‘double match-ups’ against teams in their own group, and less against teams at the other end of the spectrum.

This is who each team plays twice in 2018.

Ladder position sometimes hides the ‘true’ relative strength of a side. Nevertheless the AFL got pretty much what they intended in terms of matching each team’s strength with the combined strength of the teams they play twice, based on rankings at the end of 2017 (see table below). The main exceptions were that ‘middle six’ side the Western Bulldogs probably got an easier set of ‘double match-ups’ than ‘bottom six’ side Fremantle, and that ‘middle six’ side St. Kilda got a set that was closer to a ‘top six’ side.

(Note that, in the table below, combined ranking points have been reversed so higher points means an easier fixture. Also, points were adjusted so that their sum is zero.)

How the fixture has ended up working in 2018

Of course though teams improve and decline, and so the strength of the fixture at the start of the season is different to how it actually turns out. In 2018 the teams that have improved the most include North Melbourne, Melbourne, Fremantle, Collingwood, and West Coast (see table below). Facing these sides twice is now a tougher prospect than it first appeared. Conversely the biggest declines in performance have been from Adelaide, St. Kilda, the Western Bulldogs, and Carlton.

If we re-rank the strength of each team’s ‘double match-ups’ we see some significant changes for some teams (see table below).

Top sides Richmond and GWS now have much weaker fixtures than originally intended, as they play Adelaide and St. Kilda twice. Their fixtures are now closer to ‘middle six’ sides.

Meanwhile St. Kilda and the Western Bulldogs now have much stronger fixtures than originally intended, as they play Melbourne and North Melbourne twice. Their fixtures are now closer to ‘top six’ sides. So is Essendon’s, due to improvements in the performances of Collingwood, Fremantle, and Hawthorn.

Melbourne and North Melbourne – which had an easy set of return matches already – have benefitted the most from changes in form in 2018. Of the five teams North Melbourne play twice, four of them are amongst the five current weakest teams: Gold Coast, Brisbane, the Western Bulldogs, and St. Kilda. Two of those sides – the Dogs and Saints – were ‘middle of the pack’ sides when the fixture was originally constructed. Melbourne plays three of the big decliners twice - the Dogs, Saints, and Adelaide.

Ultimately the fixture doesn’t turn you from a ‘good’ side to a ‘bad’ side, or vice versa. St. Kilda, the Western Bulldogs, and Essendon – all currently outside the eight – probably would have a low chance of making the finals even with a friendlier fixture. But it can help you at the margins. For North Melbourne, currently sitting eighth, it may mean the difference between making the finals and missing out. The Kangaroos beat the Dogs by just two points on the weekend; against an opponent that was any stronger they may not have snuck home.

Sunday, June 17, 2018

AFL Power Rankings: Round 13 2018

The Adelaide Crows were generally expected to be a very good side again in 2018. However their run of injuries shows how a good side can be transformed into a middling one.

Adelaide – ‘best’ in 2017, ‘below average’ in 2018
The ‘best’ team of the AFL season does not always win the premiership. In 2017 Richmond was the best team during the finals series, even after accounting for their home ground advantage, and hence they were premiers. However, the team they beat in the Grand Final – the Adelaide Crows – were generally the strongest team overall in 2017, and they were close to the best side in 2016 as well.
For a fair part of 2018 though the Crows have been below average, and are now unlikely to make the finals series. Their average net margin in 2018, adjusted for estimated home ground advantage and opponent strength, is -2 points. However that is held up by a good start to the season (see chart below), including wins against Richmond and Sydney. From Round 6 onwards it is a much worse -14 points, including a thumping loss to Melbourne. The Crows’ ranking points have dropped in seven of the past eight weeks, and they have lost the most ranking points – about four goals worth – of any team in 2018.

Over the past two seasons the Crows had been a powerhouse in both the midfield and the forward line. In 2017 they ranked highly across many of the main measures for which midfielders are the big (but not the only) contributors, particularly disposals and inside 50s (see table below). In addition their forward line was brutally efficient, ranking at or near the top per inside 50 for points, goal assists, and marks inside 50. Adelaide’s performance has fallen across most of those areas in 2018. They are still OK in some of them, but they no longer look like a premiership contender.
Injuries have significantly affected the Crows in 2018

For those who follow the AFL injury list a main reason behind the Crows’ decline in performance is not much of a mystery. Many of their top contributors in 2017 have missed games through injury in 2018. Their ‘top’ 13 players in 2017, accounting for field position – excluding Jake Lever, who has left the club – have played only two-thirds of the possible matches in 2018, compared with over 90 per cent in 2017(see table below). Brad Crouch and Brodie Smith have not yet played a game in 2018, vice-captain Rory Sloane has missed nine out of 13 games, captain Taylor Walker has missed five games, and Matt Crouch and Tom Lynch have missed four games each. (Charlie Cameron, a handy forward, also left the club after the 2017 season.)

Further the players affected by injury have generally produced less per game when they have played. This is indicated by the big drops in their average SuperCoach points per game in 2018 compared with 2017. However even some of the 2017 stars who have been mostly available – ruckman Sam Jacobs and forward Eddie Betts (who has also missed matches) – have seen their production drop. This is possibly because they are now relatively old (both are over 30), or because they have been affected by the absences of other star players, or both. (The Crows’ pre-season training camp has been blamed for affecting Betts’ form, but I’ll take Betts’ word that it hasn’t.)
As a result of these injuries Adelaide is missing some of its ‘midfield grunt’ from last year. The Crouch brothers, Sloane, and Smith were among the Crows’ top eight for both disposals and inside 50s in 2017. Some of these losses have been offset through increased production from three other players – Hugh Greenwood, Paul Seedsman, and Cam Ellis-Yolmen – and the addition of Bryce Gibbs. However they are not of the level of the Crows’ midfield stars from 2017.
Meanwhile in attack, Adelaide’s four main forwards – Betts, Walker, Jenkins, and Lynch – combined for 185 goals and 192 marks inside 50 in 2017. This year, halfway through the season, they have combined for only 65 goals and 53 marks inside 50. Not all of this drop in output is due to lack of availability, but again injuries have somewhat forced the load on to less capable replacements.
What does this mean for where Adelaide is at?
The Power Rankings do not adjust for who is available, but only the actual performances that teams serve up. Therefore the rankings have probably been overrating Adelaide for much of this season, at least in terms of their current capabilities.
However if some more stars return then the rankings may start to underrate the Crows. But how good can they be? Brad Crouch is out for the season, and Brodie Smith is out indefinitely. Rory Sloane is apparently a couple of weeks from returning. Possibly the more worrying trend for the Crows is that their stars have often not played at the levels of last year even when they have returned from injury. Possibly even more worrying, from a finals perspective, is that Adelaide play six of the top nine ranked sides in their remaining nine matches. Hence it’s looking likely that the Crows may have to give up the 2018 season as a 'lost year', and hope to return to their former heights next season.

Sunday, June 3, 2018

AFL Power Rankings: Round 11 2018

If the Gold Coast Suns do actually want to avoid the ‘ignominy’ of finishing last then they may well be thankful for their early season wins.

The Gold Coast Suns are bad (for an AFL team of skilled footballers). They have been last on my rankings since Round 21 of last season, after their also relatively bad cross-state rivals the Brisbane Lions improved.
The Suns started the 2018 season off well. They beat North Melbourne, and then comfortably beat Carlton in Victoria. Therefore, even though they were still ranked last after two rounds I felt a bit sheepish about it, and conceded that they looked ‘to have improved a fair bit in 2018’.
Nope, should have stuck to my guns on that one … (and to some extent I did.) From Round 3 onwards the Suns have been every bit the worst team in the league. Their average net margin since then, adjusted for estimated home ground advantage and opposition strength, has been an awful -40 points (see chart below). Good teams like West Coast (R4), Melbourne (R8), and Geelong (R11) have chewed them up, each of them winning by over 10 goals.
However, Gold Coast is still unlikely to finish in last place in 2018. The Suns have three wins in 2018 – their third being a close win against Brisbane – compared to Carlton and Brisbane with one win, and St. Kilda with one win and a draw. With home matches to come against Carlton, St. Kilda, and Brisbane, and three wins in the bank, ladder simulations usually have them out of last place. So the Suns should perhaps be thankful for their decent early-season form, assuming that they actually don’t want to finish last to get the number one draft pick (and the AFL does not give them a priority draft pick anyway).
The Suns are relatively bad at scoring, and relatively bad at getting themselves in a position to score, ranking down the bottom with Carlton in points and inside 50s per match. They have few ‘top-tier’ players (and they may lose one of them in forward Tom Lynch after this season) and, to say a similar thing, they have far too many players at the lower end for performance. Many of their top draft picks that should be maturing now either haven’t worked out, or – in the cases of Josh Caddy and Dion Prestia – have been helping Richmond to win the flag over the past year.
Though they may not finish last, things can mostly only get better for the Suns from here.
P.S. Depending on how things go I may not update the rankings for a few weeks. Fortunately, though this wasn’t the plan, this coincides with the ‘bye’ weeks in the AFL, so there’s less happening anyway. Just remember that if one team thumps another to give them about half a dozen ranking points.