Sunday, September 30, 2018

AFL Power Rankings: Finals 2018

It was an even AFL season at the top, but when the West Coast Eagles had their two big forwards they were perhaps a touch above the rest.

In terms of top AFL teams, 2018 was a weird season. No team appeared to be as strong as the ‘great’, or even very good sides of recent years, with Richmond the only team during the season to get close to that level. Arguably the best teams going into the finals series – Richmond, Melbourne, and Geelong – all had big losses that eliminated them from the finals, while ‘mid-range’ good sides Collingwood and West Coast emerged as the in-form teams in September.
The result is it’s pretty hard to say, standing at the end of the 2018 season, who the strongest team of the year actually was. We do now know who the premiers were though.
Maybe the ‘top’ team was the Eagles all along
My ranking system, like many other AFL ranking systems, does not account for players missing through injury. Generally this probably doesn’t matter too much, unless a team has an ‘epidemic’ of them. There is enough evidence through the season however to say that this year’s premiers, the West Coast Eagles, were a much better side when their two big forwards – Josh Kennedy and Jack Darling – were available.
First, the main statistic: the Eagles were undefeated at 13-0 when both Kennedy and Darling played, and 6-6 when one of them was missing. Wins and losses can sometimes be a bit deceiving, because it depends on who you played, but that is enough games to suggest that something was different.
We can also look at the Eagles’ adjusted net margin – i.e. their net margin adjusted for estimated home ground and opposition strength – to see how much better they were with a full forward line (see chart below). When West Coast were missing either of or both of Kennedy and Darling their adjusted net margin in 2018 was a relatively mediocre +5. When both were in the side it was +28. That’s not historically dominant by any means, but it would have marked the Eagles out as the top side of 2018.

But perhaps that understates the Eagles a little as well. They had a few struggles to put away bad sides even when they had their two big forwards, beating Carlton by only 10 points, St. Kilda by only 13 points at home, and Fremantle by only 8 points. (These are the negative bars you can see for the Kennedy/Darling games in the chart above.) Against three of the top sides though they had some amazing games, beating Richmond by eight goals, Melbourne by 11 goals in the Preliminary Final, and Collingwood by six goals in their first meeting at the MCG. So with a ‘full’ forward structure they could be really good when it counted most.
West Coast converted more efficiently up forward… except in the Grand Final
Further proof that Kennedy and Darling improved the Eagles’ performance is that the Eagles were considerably better in the area of the ground that those two players could influence the most – namely, up forward.
As pointed out in an ABC article this week by the HPN guys West Coast was averaging almost 2 points per inside 50 with Kennedy and Darling in the side, whereas without those two they were at around the league average of 1.54 points. In other words, with 50 forward entries they would be expected to kick about 100 points with their two big forwards in the side, compared to about 80 points without them. In those aforementioned matches against Melbourne, Richmond, and Collingwood they didn’t have a major advantage getting the ball inside 50 in any of them. The Eagles’ ‘forward efficiency’ loomed as the main way that they could win the Grand Final.
Except that it wasn’t … the Eagles could only kick 79 points from 63 forward entries on the weekend. Collingwood’s defence through the finals was fantastic – holding both Richmond and GWS to under 60 points – and it was almost enough to beat the Eagles as well.
Instead the Eagles won through weight of inside 50 entries, which were 63 to 48 in their favour. Norm Smith Medallist Luke Shuey and Dom Sheed dominated, amassing 70 possessions of which 33 were contested, 17 clearances, and 14 inside 50 entries (Sheed kicked the winning goal to boot). The Eagles’ midfield was fairly decent all season but Shuey shone on Grand Final day. Still with one less goal I would be talking about how good Taylor Adams and Tom Langdon were yesterday instead ... 
That’s it for the 2018 AFL season, and the 2018 rankings. I wouldn’t call it one of the most memorable seasons, but we did have some good matches – the Showdowns, Melbourne v Geelong in the home and away season, Saturday afternoon in Round 20, and fortunately the Grand Final itself. We also don’t really have a strong premiership favourite for next year, which should help to make things exciting. I’m going to rest now, and hopefully come back with some new ideas for 2019.

Tuesday, August 28, 2018

AFL Power Rankings: Round 23 2018

So at the end of the 2018 AFL home-and-away season Richmond is the top-ranked side, although only narrowly over Geelong and Melbourne.

The Cats and Demons closed the gap considerably over the final two weeks – Geelong from annihilating ‘bad’ teams, and Melbourne from finally beating good teams. The Tigers also slipped a bit, although whether that indicates teams are actually playing better against them or that Richmond was just relaxing a touch before the finals (or both) remains to be seen.

Outside of that, the only highly-ranked team that did not qualify for the finals is Essendon. The Bombers’ high ranking reflects their strong finish to the season, but ultimately their poor start cost them a finals spot.

Predicting the finals series

For the past three years I’ve used the end of home-and-away season rankings to predict how the finals series will play out. Basically this is done just by comparing who has the higher ranking points, adjusted for any estimated home ground advantage.

In that time the Rankings have predicted five of the six Grand Finalists, and two of the three premiers. The miss – like every other AFL ranking system in existence – was the Western Bulldogs in 2016. These predictions however are purely for fun and interest’s sake, and not to coax you into betting your life savings.

Unsurprisingly, the Rankings pick Richmond to win the premiership for a second straight year. Unlike last year though I’d say the Tigers would still be considered the team with the best chance if one considered the likelihood of each team winning each potential match-up, not just the match-ups shown above. I’m picking West Coast, with two home finals from finishing second on the ladder, to be the other Grand Finalist.

Again though, I’ll emphasise three main potential problems with this straight head-to-head prediction method. The first is that just one result going against the prediction can change the outlook considerably. The second point, related to the first, is that our assessment of each team will change as we progress through the finals series.

And the third is that it doesn’t show how close the teams are in likelihood to winning. According to the Rankings there is basically nothing between Melbourne and Geelong. Melbourne should be seen as almost as likely as Geelong to progress as the Cats do above.

I’ll be back again after the finals series finishes with the final rankings for 2018. How soon after, like last year, may depend upon how far my Tigers go.

Sunday, August 19, 2018

AFL Power Rankings: Round 22 2018

You have to beat the good sides to win the premiership. Based on their form so far against the likely finalists, which teams should be a bit worried?

Melbourne’s bizarre season 

Today Melbourne qualified for its first AFL finals series since 2006 with an excellent win against the West Coast Eagles. That win aside though, Melbourne’s struggles against the top sides in 2018 have been well noted. They’ve had twelve wins and one loss against teams that are currently in the bottom half on the ladder. Against teams in the top half they’ve had seven losses and just the one win.

Prior to the Eagles match the gap in the Demons’ relative performances against top and bottom half teams was one of the largest in VFL/AFL history. (See this helpful graph from Insight Lane – by a nice coincidence I had already chosen the topic for this week’s post when this insight was given.) Usually good performances against good sides and not-so-good sides tend to go together. Strangely, two of the largest gaps ever in relative performance have come in the past two seasons – last year it was Port Adelaide who confounded rating systems by destroying ‘bad’ teams and capitulating against the good ones.

Melbourne has been highly rated by my ranking system for most of the season, because of its ability to annihilate lower teams. This has left me feeling more and more sheepish as the Demons have racked up losses against the top sides.

The best way to explain Melbourne’s high ranking is this: the Rankings take into account performances against the whole league, not just the top half. It is true that the Rankings have tended to overestimate Melbourne’s chances against the top teams this season. By the same token though, they have tended to underestimate the Demons’ victory margins against the lower teams.

It’s beating the top teams that matters now – which likely finalists should be worried?

However as we get to the finals series, it’s only a team’s performances against the teams that remain that matter. Based on this, once they get past the joy of qualifying for their first finals series in twelve years the Demons should be a bit concerned about their ability to progress.

Melbourne’s average adjusted net margin this season against the other likely finalists is -8 points. After adjusting for opposition strength and home ground advantage this makes them the equivalent of a below average side when they come up against the best (see table below). Richmond, Hawthorn, and Collingwood all won by large margins against the Demons, and Sydney beat Melbourne last week on its home ground.

For the other likely finalists, Collingwood’s inability to beat the top eight teams has also been well noted. The Magpies have only beaten one top eight team: Melbourne (although they came close to beating Sydney). Their best performances have come against the next tier of sides that are just outside the eight – Port Adelaide, North Melbourne, Essendon, and Adelaide. Against the likely finalists they have been the equivalent of an average side. Collingwood and Melbourne are two of the better sides overall, but their ladder positions have been helped a little by friendly fixtures.

Less well noted is GWS’ struggles against the better sides earlier this season. The Giants were thrashed by Geelong, and were also well beaten by West Coast. They have also lost to Sydney twice. Some of those performances may have in part been affected by injuries, but that may not be much comfort to the Giants as injuries have recently hit them again.

Who has done well against the best?

Minor premiers-elect Richmond has performed the best overall against the top teams. The Tigers have had some struggles outside of Victoria, but they have beaten every team they have played in their home state. Unless they lose in the first week of the finals they will play at the MCG for the duration of the finals series.

Also doing well against the top teams are Sydney, West Coast, Hawthorn, and Geelong, although for somewhat different reasons.

Sydney beat the Eagles both at home and away and has also beaten GWS twice this season. Most notably the Swans have had excellent form away from home, beating Geelong, Hawthorn, and Melbourne.

West Coast’s best win for the season was their big win against Richmond at home. They have also shown they are capable of winning in Victoria against good opposition by beating Hawthorn and Collingwood there.

Hawthorn thrashed Melbourne, and also easily beat Collingwood in the first match of the season. The Hawks beat Geelong twice (albeit narrowly), and have generally been close in their losses against the top sides.

Geelong is the second-highest team on the Rankings but will likely finish in seventh or eighth spot on the ladder, in part because of their tough fixture. The Cats’ form against the top teams has been fine: they thrashed GWS, and have been good or at least OK in most of their matches.

You may step it up though

So should we just be waiting for the seasons of Melbourne and Collingwood to come to an abrupt end? Of course not. Last year for example we saw Richmond play considerably better against teams in the finals series than they had done earlier in the season, including a massive (home ground advantage aside) 124 point turnaround against Adelaide. The Western Bulldogs substantially stepped up their performances in September the year before.

Melbourne and Collingwood are good teams. They may even be capable of matching it with the best teams. They just haven’t given a whole lot of evidence during the season that they can yet.

Sunday, August 12, 2018

AFL Power Rankings: Round 21 2018

With just two more goals in the past two weeks Port Adelaide would currently be sitting in third position on the ladder. Being near the middle though may be a better reflection of where the Power are at.

History repeats for the Power, but this time they were less ‘unlucky’

The first two chapters of ‘Footballistics’, the AFL analysis book released a few months ago, recount how Port Adelaide lost a home elimination final last year, with an after-the-siren goal by West Coast.

Port Adelaide had been a better side than the Eagles throughout the year, and the book essentially argues they were probably a better side on the night as well. However they lost the match because they were unusually inaccurate in front of goal, and West Coast was the opposite. As a result West Coast finished in the ‘top six’ teams, and Port – though they had been close to finishing in the top four – finished in the ‘middle’ of the ladder in seventh.

This weekend history repeated as the Eagles again beat the Power after the siren at Adelaide Oval. This year though the result more likely reflected that West Coast may actually be the better team.  

The Eagles have improved somewhat in 2018, and currently sit second on the ladder, three wins ahead of Port. Also unlike last year, West Coast easily won the inside 50 count. That indicates this time around the Eagles won because they created more opportunities to score, not because they were uncannily accurate in front of goal.
Port Adelaide have generally been average in 2018
Defenders of Port Adelaide may point out that, with a three-point loss last week to Adelaide, and a four-point loss this week, the Power were only a couple of kicks away from now sitting third on the ladder. On the other hand Port has also won some close matches this year as well, including the first ‘Showdown’ against Adelaide. The Power have three wins and four losses this year in matches decided by 10 points or less, which is neither significantly ‘lucky’ or ‘unlucky’.
Below Richmond there has been a bunch of teams this year that have been pretty good. This includes West Coast, as well as three of the sides in the thick of the battle for third and fourth – GWS, Collingwood, and Hawthorn.
I’d also say it includes Geelong, despite the Cats currently sitting in ninth position – they’ve had a tough fixture, with having to play Richmond, Melbourne, Hawthorn, and Sydney twice. Melbourne and Sydney are a bit harder to pin down after the Swans’ win against the Demons on the weekend: Melbourne’s thrashed the weaker teams, while the Swans have generally struggled in recent weeks.

The Rankings don’t include Port Adelaide in that group. I’m not alone – the mathematically-minded consensus is that Port is ‘splashing about at sea level’. Returning back to a table I showed a few weeks ago the Power have had less ‘good’ and ‘very good’ performances than most of the other teams in the top eight (see table above).
The Power’s two best wins in 2018 have been against Sydney and Richmond. That is some progress from last year, when the Power were notoriously unable to beat teams in the top half of the ladder. But what they were able to do in 2017 was put away bad sides. Last season they had six wins by over ten goals – this year it has been none. Despite some decent recruits, the Power were probably a better team last year.
Port’s strengths: defence, and Robbie Gray
Port Adelaide’s defence in 2018 has been very good, with only Richmond having conceded less points. The Power currently lead the league in ‘one percenters’ (spoils mainly), with Dougal Howard recording the most of any player, and Tom Jonas near the top as well. Port has also conceded the least marks inside 50 of any team.
With Port though it is mainly a case of being decent, but not strong. Arguably they only have one ‘superstar’ at their position – the remarkable midfielder/forward Robbie Gray (maybe Paddy Ryder as well, when less hampered by injury). Gray got the Power over the line in the first Showdown this year with his six goals, and almost got them over the line with four goals in the other. Other than Gray they have a few pretty good players, including Ollie Wines, Justin Westhoff, Chad Wingard, and Travis Boak. It’s enough to keep them mid-range, but almost all of the top eight sides have more top-end talent than that.
The slither of hope: ‘do a Bulldogs’
In summary then Port Adelaide currently sitting in seventh is probably a fair reflection of their ‘true’ strength at the moment. Of course the ladder is so close that an upset win against Collingwood next week could considerably change the outlook for them. Otherwise though it looks like they will finish somewhere in the bottom rungs of the final eight, if they make it at all.
That actually puts them in a similar position to the Western Bulldogs when they won the premiership a couple of years ago. The Bulldogs’ amazing 2016 run though should be far from the preferred model for obtaining a premiership. More likely the Power will have an early exit, to be left wondering what else they can do to take the next step.

Sunday, August 5, 2018

AFL Power Rankings: Round 20 2018

The AFL this year actually has a clear set of ‘bottom six’ teams. However, some of those teams are still much worse than the others.

With eighteen teams in the AFL, it’s somewhat natural for the league to think of the ladder as consisting of ‘three groups of six’.

This is what the AFL does in terms of determining its fixture each year. Teams in the ‘top six’ – based on last season’s finishing positions – will in theory have harder fixtures than those in the ‘middle six’ or ‘bottom six’ (though this doesn’t always work).

Potentially more significantly and controversially, under the AFL’s proposed ‘17-5’ fixture teams would be divided into ‘three groups of six’ after playing each other once in the first 17 rounds. The ‘top six’ teams would play for the top four spots in the final five rounds, the ‘middle six’ teams would play off for finals spots, and the ‘bottom six’ teams would play to determine who gets the highest draft picks.

Usually teams don’t fit neatly into groups of six in terms of ability. For example, last season Collingwood finished in the ‘bottom six’ in thirteenth position, and received a relatively easy fixture as a result. However, based on the Power Rankings Collingwood was an ‘average’ side that was about as good as the sixth-placed side, the West Coast Eagles. The Magpies and Eagles are among a bunch of ‘average’ sides that have taken the step up to being ‘good’ this season, but if you only consider ladder position the Pies’ rise seems more dramatic.

The ‘Dismal’ Six

This year though there has been a clear ‘bottom six’ sides – Fremantle, the Western Bulldogs, St. Kilda, Brisbane, Gold Coast, and Carlton. These six teams are all at least three wins behind every other team in 2018, with three rounds left. They are also clearly the six bottom-ranked sides, and have been since way back in Round 4.

The Lions have been OK recently

Nevertheless that does not mean these six teams are all about as equally ‘bad’. In particular the Brisbane Lions have been pretty good over the past few weeks (see first chart below). Indeed, despite currently sitting in sixteenth on the AFL ladder, the Rankings think the Lions are closer in ability to second-placed West Coast than seventeenth-placed Gold Coast! (See second chart below.)

The Lions are zero wins and five losses in matches decided by less than ten points so far this season. With at least a couple of wins in those close matches their ladder position would probably be a ‘fairer’ indication of their ability. On the bright side, with higher draft picks currently going to lower teams, they may end up with a higher draft pick than a team of their ability would usually get.

Gold Coast and Carlton are in depths of their own

Three of the remaining ‘bottom six’ sides – Fremantle, the Western Bulldogs, and St. Kilda – have been pretty ‘bad’, but not historically so. They have generally hovered around being three or four goals per game below average (see first chart above). They’re closer to Gold Coast than West Coast, but not by a huge amount.

Freo and the Bulldogs both have a couple of ‘stars’ holding them up – Nat Fyfe (until his injury) and Lachie Neale at the Dockers, and Marcus Bontempelli and Jack Macrae at the Doggies. The Saints have Jack Steven, and also a ‘rising star’ in young forward Jade Gresham. It’s not a great near-term outlook for any of them, but it’s not awful either.

Gold Coast and Carlton though are way below everyone else, as shown by them both losing by around 100 points on the weekend. They have generally been around six to seven goals per game worse than an average side (see first chart). Between them they have had 11 losses this year in excess of ten goals.

Carlton though at least has a genuine ‘star’ in Patrick Cripps, and a ‘rising star’ in Charlie Curnow. Gold Coast is going to lose one ‘star’ and co-captain this season in Tom Lynch (though they should receive good compensation), may lose the other in Steven May, and really do not appear to have much else in the way of ‘stars’ or ‘future stars’ in the near-term. Though the Suns are currently separated only by percentage from fellow Queensland side the Brisbane Lions, the gap between them may really be much, much larger.

Sunday, July 29, 2018

AFL Power Rankings: Round 19 2018

I feel like taking the week off writing something detailed this week.

An odd thing I noticed about the rankings though: nearly all of the Victorian teams are rated higher by my rankings than they are on the current AFL ladder. Which means of course that nearly all of the non-Victorian teams are rated lower.

Three of the top five sides on the current ladder are non-Victorian: West Coast (second), Port Adelaide (fourth), and GWS (fifth). On my rankings all of the top five sides are Victorian.

There's no Victorian bias in the rankings formula! (At least not intentionally …) And in some areas of the rankings the teams are all pretty close together anyway. But maybe the rankings suggest that teams like Melbourne, Hawthorn, and Geelong - currently filling out the bottom three spots in the top eight - are more within striking distance than you may think.

Sunday, July 22, 2018

AFL Power Rankings: Round 18 2018

The Sydney Swans – consistently a good team in recent years, and one of the best teams coming into the 2018 season – are in a spot of bother.

The Sydney Swans have been a good team for most of the past fifteen years. So if they have a bad few weeks, there is a fair amount of faith they will come back. Even when they lost their first six matches last season they were still considered a decent side. They proved to be even better than that – ending up as one of the best teams in 2017 – but coming from so far back made it a hard path to the premiership.

This year the Swans have been generally good again. However some worrying signs are starting to emerge for one of the AFL’s most reliably high-performing sides.

The Swans had an absolute shocker this week … but maybe we shouldn’t have been quite as surprised as we were

On the weekend, the Swans lost by four goals to the very lowly-ranked Gold Coast Suns. After adjusting for Sydney’s home ground ‘advantage’ (we’ll get to this) and the strength of the opposition, this is estimated to be the equivalent of an 11 goal loss against an average side.

That is the Swans’ worst ‘adjusted net margin’ since losing to Melbourne by 73 points in Round 17 2010. In terms of the rankings it puts them now just above average, and in eighth place.

Sydney has lost the most ranking points of any team in the past five matches, although until this week’s disaster they had still been going OK in terms of their margins. However in two of those losses – against Richmond, and Geelong – the Swans’ relative accuracy in front of goal may have made things look closer than they were.

Sydney kicked 11.1 against Richmond, meaning they had 12 scoring shots to the Tigers’ 23, and they got the ball inside 50 only 70 per cent as much as the Tigers did. Against Geelong the Cats kicked a highly inaccurate 8.23, meaning they had 31 scoring shots to the Swans’ 14. The Swans got the ball inside 50 less than 80 per cent as much as Geelong did.

Hence if the rankings were based on scoring shots rather than margins we would have already seen Sydney start to dip. On Matter of Stats’ rating system based on scoring shots the Swans were already considered just an average team going into this round.

Away sweet away    

An unusual aspect of the Swans’ 2018 season is that they have been really good away from their home ground, and pretty bad on it. In terms of wins and losses they have three wins and five losses at home (not including their ‘neutral’ match against GWS), and seven wins and one loss when playing away.

In terms of net margins adjusted for home ground advantage and opposition strength, Sydney has an average adjusted net margin of -17 at home (see chart below), which includes losses to Gold Coast and Adelaide. Playing away their average adjusted net margin is +29, including wins against West Coast, Geelong, and Hawthorn. It’s all a bit weird … (I’m sure someone can try to explain what is going on, but I’m not going to attempt it here.)

Given the Swans’ horrible home and great away record I’ve seen some Sydney supporters suggest that they are better off finishing seventh or eighth, and then trying to win four away finals to win the premiership. And indeed Sydney has been a very good team ‘on the road’ this year. However, as last year demonstrated for the Swans, even for a very good team having to win four straight finals is not the ideal path.

Sunday, July 15, 2018

AFL Power Rankings: Round 17 2018

The Brisbane Lions have not only been the most improved side in the AFL over the past few weeks, they may also have been its best.

It has been a good few weeks for the Brisbane Lions. The Lions have been a below average to relatively poor side for almost a decade. On the weekend however they beat finals aspirant Hawthorn by over five goals in Tasmania, where the Hawks have been highly successful. The week before they thrashed Carlton by 65 points, this in turn followed a 55 point beating of Fremantle in Perth.

Even after adjusting for the relative weakness of their opponents the Lions have the highest total adjusted net margins over the past few weeks (see chart above). If this was the start of the season people may well have been falling over themselves to declare Brisbane the big improvers of 2018.

Brisbane has still been below average across 2018 as a whole. Their three weeks directly preceding this ‘hot’ streak were poor, as they were comfortably beaten by Essendon and GWS at home, and well beaten by North Melbourne. The Lions also got destroyed by Richmond earlier in the season (a match in which they kicked only two goals), were easily beaten by St. Kilda, and lost to the bottom-ranked Gold Coast Suns. On the bright side, they did have another strong win against Hawthorn earlier in the year.

The Lions’ improvement has been largely driven by their forward and defensive efficiency. They have amassed 51 goals over the past few weeks and conceded only 25 goals, despite getting the ball inside 50 about as much as their opponents (see table below). AFL teams in 2018 have averaged about 1.5 points per inside 50. Over Round 15 to 17 Brisbane has scored an astonishing 2.25 points per inside 50, and conceded only 1.20 points per inside 50 against.

The Lions’ defensive performances these past few weeks is even more amazing when you consider that their best defender, Harris Andrews, has been missing through injury. Andrews’ absence has been ably and surprisingly covered by Josh Walker. Despite missing the past three matches Andrews still has the league’s second-highest number of ‘one-percenters’ (spoils and other useful things) in 2018, averaging almost 12 per game. Walker has done a pretty good Andrews impression, recording 37 one-percenters over his past four matches. He had only four one-percenters in his four matches before that, and has never averaged more than three per game in his previous six seasons, having played the majority of his career as a forward.

Up forward for the Lions Eric Hipwood has been the star, with 11 goals and 14 marks inside 50 over the past three weeks. But a fair bit of the help has still come from the midfield, including Dayne Zorko’s five goal assists against Carlton – a career and league-wide season high – from just seven inside 50 entries. While the midfield hasn’t been outstanding in terms of the amount of times they have got the ball into attack, they have been pretty good at setting up scoring opportunities when they do.

Is this a turning point for the Lions? At the least – as long as it’s not just that they play well against the Hawks – they might become average again. Given how the 2010s have generally gone for Brisbane that would be something in itself.