Sunday, April 2, 2017

AFL Power Rankings: Round 2 2017

Last year’s top ranked team Sydney falls a bit further this week after losing again to its Grand Final conquerors the Western Bulldogs. Despite its 0-2 start to this season the Swans are still highly regarded by the rankings, and are still considered a good chance to play in the finals. Matt Cowgill showed over on his column on ESPN that Sydney was – by his ratings – still a 60 per cent chance to make the finals even if it lost this week, and would probably still be considered a better-than-even chance of making it after Round 4 as long as it did not lose its first four matches. That’s a fair bit better than the 2 per cent chance Herald Sun journalist Jon Ralph gave teams starting 0-2 this week. I’d say that Ralph’s figure, which is based on the amount of teams that have recently made the finals after starting 0-2, probably indicates that it’s rare for top teams to start the season with two straight losses.

At the other end of the rankings Essendon remains near the bottom despite winning their first two matches, albeit this week’s win was against the bottom-ranked club Brisbane. No adjustment has been made in the rankings to account for the Bombers having regained some of their best players who were banned from playing last year by the World Anti-Doping Agency. In general because I use a simple formula I don’t make any adjustments for player movements, departures and returns.

I think this works fine in most cases but is probably much less accurate in a significant case like this one. Another consequence is that teams that play Essendon are perhaps penalised more than they should be. For example, Brisbane’s modest 27 point loss this weekend was considered equivalent to a whopping 74 point loss once home ground advantage and Essendon’s relative ‘strength’ – still largely based on its depleted side from last year – was taken into account.

Of course if Essendon performs above its level of last year – which most people expect they will – then it will move up the rankings to its ‘true’ level of competency soon enough. (Similarly the performances of clubs that play against Essendon will naturally adjust in the rankings as well.) Note though the Bombers were playing very badly in late-2015 before those players were banned. They are playing much better so far in 2017, but Essendon has a history over the past few years of starting the season off much better than they finish it. It has done this basically every year since 2012 and repeatedly made my rankings look ‘foolish’ until they drop off. So while I definitely think Essendon is better than the current rankings suggest I’m not prepared to say that the rankings are waaaaaaaaay off just yet.


Footy Maths said...

I wouldn't mind betting Ralphy also got the 2% data from either MoS or The Arc, who tweeted (or was it on ESPN website) this week.

Troy Wheatley said...

I think it was just basically that of the past 50 teams that started 0-2 only one has made the finals. But if you go back a bit before that a few more teams have. The Arc showed 18% of teams have since the final eight began this week.