Tuesday, March 27, 2018

AFL Power Rankings: Round 1 2018


Welcome back to the eighth season of my Australian Football League Power Rankings, my attempt at taking a step back from the ‘noise’ of the week-to-week AFL results and assessing where every team is ‘truly’ at.
Basically, the Power Rankings work like this. They take each team’s last season worth of games, with more recent games receiving a higher weight. Then they add up a team’s net margin in each of those margins, adjusting for the strength of the team’s opponent and home ground advantage. (You can find the details of the ranking formula here.) So, for example, losing narrowly to the Adelaide Crows at the Adelaide Oval can be worth more than beating a lowly-ranked team like the Brisbane Lions.
When we last left things after the 2017 season, I would have roughly characterised the 18 teams as follows:
Really Good: Adelaide, Richmond, Sydney.
Good: Geelong, GWS, Port Adelaide.
Average: Collingwood, Essendon, Hawthorn, Melbourne, St. Kilda, West Coast, Western Bulldogs.
Below Average: Carlton, North Melbourne.
Well Below Average: Brisbane, Fremantle, Gold Coast. 
So, after the first round of the new season, where are we at?

Sydney extends its lead in top spot with a five-goal win against the West Coast Eagles in Perth. Richmond did just enough against Carlton to maintain its ranking points, while Adelaide slipped a bit after losing first up to Essendon.

The four teams that did the most to change the rankings’ view of them on the weekend were GWS and Hawthorn in the upward direction, and their opponents the Western Bulldogs and Collingwood in the downward direction. GWS edged closer to ‘really good’ with an 82 point thrashing of the Dogs, who are now slipping further into ‘below average’ territory. Hawthorn meanwhile had a 34 point win against a team that the rankings had more or less considered a ‘peer’ going into the season, edging the Hawks closer towards the ‘good’ category.

Finally, for those people who have been following my AFL Women’s Power Rankings over the past couple of months, how did that end up? Well actually, despite the Brisbane Lions’ women’s team missing out on the premiership to the Western Bulldogs they ended up as the top-ranked side, given that they only lost by a goal playing in Melbourne. Which is really no consolation at all, other than to say that they put in a good performance on the weekend, and would have been a worthy premiership winner. Well done to the Doggies though, who were just as worthy, being one of the best-performed sides for most of the way through. We’ll see you again for the Women’s Power Rankings – with two new sides – in 2019.

2 comments:

Anonymous said...

Hi are can these points be taken to give a literal net difference in terms of actual game points obviously also factoring home advantage on top?

Troy Wheatley said...

Yes, you can roughly interpret it that way. I’d probably be more inclined to say that, for example, the Swans are rated as ‘about five goals per game’ better than Melbourne than to be exact about the number of points. The system is a bit rough rather than optimal. But yes, that would be the general idea.