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.