Monday, April 2, 2018

AFL Power Rankings: Round 2 2018

GWS and Port Adelaide have had good starts to the 2018 AFL season. But should we rate them yet as highly as 2017’s late-season powerhouses?

After two rounds of the 2018 AFL season the four undefeated sides are Greater Western Sydney, Port Adelaide, Hawthorn, and Gold Coast. GWS and Port in particular are getting some consideration as premiership contenders on the back of their early season form.

The Power Rankings though still rate the Giants and Power slightly behind last season’s top triumvirate of Sydney, Adelaide, and Richmond. Why are they not rated as highly? Should they be?

GWS and Port have earned by far the most ranking points so far in 2018. Although note that most of those points really just come from one of their two matches – for GWS it is from last week’s thrashing of the Bulldogs, and for Port it is from this week’s impressive win in Sydney.

The Power Rankings do place their highest weights on those past two matches, but they also still place a fair amount of weight on results from late-2017, including last year’s finals series. To many (including myself) the details may have become a bit hazy in the break between seasons, but each of the Swans, Crows, and Tigers finished off last season much more impressively than the Giants or Power.

In their past nine matches, based on their net margins adjusted for estimated home ground advantage and opponent strength, the Swans have had six performances that I would categorise as ‘good’ (see table above). These are: their win last week against West Coast in Perth, their finals win last season against Essendon, their thrashings of Carlton and Fremantle in the late rounds of 2017, and their wins last year in Adelaide and Geelong. (Conversely the Swans also had one ‘poor’ performance in that period, which was their big finals loss to Geelong.)
The Crows have had five performances I would consider as ‘good’ in that time – their win against Richmond this week, their finals wins against Geelong and GWS, their thrashing of Port in last year’s Showdown, and a comfortable win against Essendon in Melbourne. Fewer AFL followers need reminding of how the Tigers finished off 2017 – they easily beat Fremantle and St. Kilda in the final two rounds before mowing through Geelong, GWS, and Adelaide on their way to the premiership.      
The Giants and the Power just don’t have that lengthy a record of strong performances recently. Apart from thrashing the Bulldogs last week the Giants’ only really impressive performances in their past nine matches were their thrashing of West Coast in last year’s finals and, also from 2017, another handy defeat of the Bulldogs. For the Power it was the win against Sydney this week, and last year’s 115-point final round demolition of Gold Coast.
Now if I weighted the rankings differently to place much more weight on the past two rounds then GWS and Port would come out on top. So arguing or thinking that GWS and Port are the two best sides at the moment is really just placing a relatively high weight on the two rounds that have happened so far in 2018. Or put another way, it is valuing form in the new season more highly relative to what happened during the finals of the old season.     
In any case though the Giants and Power are good sides. And when one is listing the premiership contenders in 2018, both should be considered amongst the sides with the strongest chances.    
The Gold Coast Suns, despite winning their first two matches, should not be considered amongst the top teams. The Suns beat North Melbourne and Carlton, who are both lower-ranked sides, although their margin of victory against Carlton when playing away was somewhat impressive. Because of the Suns’ dreadful end to 2017, it will be a while before the rankings even consider them as just mildly below average. Again if one placed a high weight on new season form they would be rated more highly. At the least though, on the evidence so far, the Suns look to have improved a fair bit in 2018.

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