P.P.S. AFL Power Rankings Round 18 2013: Breaking Down Each Club's Performances

Following on from yesterday's P.S. that North Melbourne has 'improved' because it has mostly eliminated its 'very bad' performances in 2013, I thought it would be interesting to break down the performances of every AFL club.

Performances are rated according to relative adjusted net margin (net margin adjusted for home ground advantage and strength of opposition) as follows:

Very Good - RANM above +40
Good - RANM above +15 and below (or equal to) +40
Very Bad - RANM below -40
Bad - RANM below -15 and above or (equal to) -40
Fair - Everything else

These performances are summarised for each team in 2013 up to Round 18 and for each team's last 22 games of 2012 (including finals) below, along with their change in ranking points in 2013 - click to enlarge:

 

 

Of the big improvers in 2013:

- Gold Coast has considerably reduced its incidence of very bad performances in 2013.
- Port Adelaide has increased its incidence of good performances and reduced its incidence of very bad performances.
- North Melbourne has increased its incidence of fair performances and reduced its incidence of very bad performances.
- Essendon has reduced its incidence of very bad performances.
- Western Bulldogs' have more bad performances rather than very bad performances.

Of the teams taking major steps back in 2013:

- St. Kilda has significantly less good and very good performances and significantly more bad and very bad performances in 2013.
- Melbourne has reduced its incidence of fair performances; that is, almost all of its performances in 2013 are bad or very bad rather than just most of them as in 2012.
- West Coast has reduced its incidence of good and very good performances and increased its incidence of bad performances.
- Adelaide has considerably reduced its incidence of very good performances.

P.S. AFL Power Rankings Round 18 2013 – More On North Melbourne’s ‘Improvement’

In this week’s AFL Power Rankings, I pointed out that the ranking system rated North Melbourne as the 3^rd most improved team so far in 2013, despite the Kangaroos going backwards on the actual AFL ladder. Below is a summary of North Melbourne’s performance in every game so far in 2013, ordered from best performance to worst. Performances are rated by North Melbourne’s relative adjusted net margin for the game, which is North’s net margin, adjusted for home ground advantage and the relative strength of the opposition. (For example, North’s win on the weekend against Melbourne gets deflated by 51 points, while their win against Richmond gets inflated by 16 points.) I have also included the ranking points the Kangas get for each game as of Round 18, with more recent games getting a higher weighting. (For example, North’s win against Melbourne, though it was of slightly lesser quality in relative terms than the win against Richmond, currently gives them more ranking points because it was more recent.)

	Relative net margin	Ranking points	Result
Rich	78	5.87	W
Melb	71	6.18	W
StK	59	3.48	W
Bris (1)	37	1.32	W
WB	25	1.19	W
Haw	25	0.98	L
Geel	22	0.62	L
WC	20	1.03	L
GWS	14	1.01	W
Carl	12	0.95	L
PA	2	0.09	W
Adel	-7	-0.37	L
Fre	-7	-0.49	L
Coll	-11	-0.26	L
Syd	-14	-0.43	L
Bris (2)	-14	-1.09	L
GC	-19	-1.21	L
Total ranking points		18.86
Average relative net margin		17

As I said on the weekend, the Kangaroos have got most of their points from three games, which are their wins against Richmond, Melbourne and St. Kilda. All their other performances gain them only a few more ranking points. (They still have a small penalty from their last five games of 2012.) But note that their very good performances have not been balanced out by some very bad ones. (North was also assessed to have the hardest draw in 2013, but relative net margin adjusts for that, and in any case they have only played Brisbane twice at this point.) Now compare this with North’s ranking points at the end of 2012. (Net margins are adjusted by how strong the teams were in 2012, and North’s first game against Essendon drops out of the final ranking for 2012, with their final against West Coast included.) 

	Relative net margin	Ranking points	Result
GWS (1)	63	0.25	W
Carl	61	3.37	W
StK	54	2.58	W
Coll	44	3.31	W
Adel	43	1.89	W
Geel	29	0.23	W
Ess	25	1.77	W
WB (2)	20	1.35	W
Melb	19	1.21	W
Rich	16	0.93	W
WC (2)	14	0.72	L
WC (1)	3	0.06	L
Syd	-1	-0.01	L
Bris	-5	-0.14	W
PA	-11	-0.31	L
GC (1)	-24	-0.38	W
GWS (2)	-26	-2.13	W
GC (2)	-27	-1.06	W
Fre	-51	-4.05	L
WB (1)	-52	-1.23	L
WC (F)	-68	-5.92	L
Haw	-77	-2.74	L
Total ranking points		-0.31
Average relative net margin		2

North still had some very good performances in 2012. But they also had some terrible performances, including the ‘Buddy Game’ in Hobart, their thrashing in the finals against the Eagles, a thrashing by the Dockers in Melbourne, and a loss against the Bulldogs (which wasn’t by much, but it’s bad because it was against ‘weak’ opposition). Indeed, their seven worst performances in 2012 were worse than their worst performance so far in 2013.

Thus, North’s improvement according to the ranking system is because they have eliminated their bad losses and other weak performances. Alas, for Kangaroos supporters, because of several close losses, this hasn’t translated to an improvement on the ladder.