AFL Power Rankings: Round 10 2012

After dropping to third last week Hawthorn are back at the top following a Buddy-led demolition of North Melbourne. The Hawks have opened up a bit of a gap from a batch of teams that are bunched together at second to fifth, including last week’s leader, West Coast, who were one of several teams to lose this week to much lower-ranked opponents.

There is some movement in the middle of the rankings as well, with Richmond and Adelaide vaulting into the “top eight”, while Carlton fall from fifth to ninth, and Essendon from eighth to tenth. Some might be wondering how the Bombers, at 8-2 for the season, can be so low. Given that the ranking system is based on “relative margins”, their weak performances against bad opposition cost them in terms of ranking points – if their matches this season against Gold Coast, Port, and Melbourne were removed they would be up in sixth spot. So if you think the Dons’ struggles against the bottom teams don’t really matter, just imagine them as the sixth-ranked team instead.

1 (3) Hawthorn 28.3 (19.6)
2 (1) West Coast 20.0 (23.1)
3 (2) Geelong 20.0 (22.2)
4 (4) Collingwood 19.9 (18.9)
5 (7) Sydney 19.3 (13.2)
6 (6) St. Kilda 12.4 (14.9)
7 (9) Richmond 10.7 (8.0)
8 (10) Adelaide 9.5 (6.7)
9 (5) Carlton 7.1 (15.6)
10 (8) Essendon 6.2 (10.8)
11 (11) North Melbourne -5.2 (2.4)
12 (12) Western Bulldogs -9.2 (-4.8)
13 (14) Brisbane -12.6 (-14.7)
14 (13) Fremantle -14.4 (-12.0)
15 (15) Port Adelaide -20.4 (-28.4)
16 (16) Melbourne -36.1 (-40.2)
17 (18) Greater Western Sydney -53.4 (-56.2)
18 (17) Gold Coast -54.8 (-54.4)

How Best-of-Five-Set Matches Benefit Dominant Male Tennis Players

This post was inspired by an article on The Economist, which went through some possible explanations for why, in recent years, the best male tennis players have dominated Grand Slams more than the best female tennis players. An addendum at the end of the article noted that part of the reason for this is that women’s matches in Grand Slams are three sets, while men’s matches are five sets, therefore making upsets more likely in the women’s game.

Not being able to calculate probabilities in my head, I was curious to see how the different match lengths affects the chances of the “better” player winning the match. Assume that a given male player and a given female player have the same probability of winning a particular set. The tables below show, for selected probabilities of winning a set that are greater than 0.5, the probability of those players winning a particular match, if their probabilities of winning a particular set remains constant. They also show the probability of those players winning a Grand slam tournament (although more caution should be taken with these probabilities, given that a player’s probability of winning a particular set is likely reduced as they progress through the tournament).

	Probability of winning match
Probability of winning set	Female	Male
0.5	0.500	0.500
0.6	0.648	0.683
0.7	0.784	0.837
0.8	0.896	0.942
0.9	0.972	0.991

	Probability of winning Grand Slam
Probability of winning set	Female	Male
0.5	0.004	0.004
0.6	0.031	0.047
0.7	0.143	0.241
0.8	0.415	0.620
0.9	0.797	0.933

So the fact that men play five sets does make a bit of difference to a dominant male player’s chances of winning a Grand Slam match (and the tournament) compared to a dominant female player’s. But it doesn’t look like it’s enough to primarily explain the greater recent dominance of Federer, Nadal and Djokovic compared to the top female players. Also, as noted in the article, there have been long periods when the top female players have been more dominant (Graf, Seles, Navratilova, Evert, etc), so the set structure just favours the top male players being more dominant, it by no means guarantees it.    

Is This The Best Richmond Team Since 2001?

At this stage of the season (Round 9) they had better records in 2003, 2005, 2006, and 2011. In '06 and '11 though their percentage wasn't too good, indicating they were a crappy team waiting to happen. In 2003 their percentage was alright but not as good as this year. This leaves 2005. In 2005 the Tigers had won 7 out of 9 games at this stage. However they had also played 6 of the bottom 8 teams. So I think there's a case to say that the 2012 version, which has had a tougher draw, is better. (Although if the 2005 team had not lost probably their best player at the time, Nathan Brown, mid-season they may well have made the top eight.)

How Even Is This AFL Season Really?

Not nearly as even as the pundits would have you believe. Take a look at this graph, which shows the variations in winning percentages and for/against percentages across AFL teams after Round 9 for every season since 2003:

2012 is actually at the top for both categories, suggesting this is the most uneven season of the past decade. However, when the pundits talk about this being an even season, they are probably talking about the top 10 or 12 teams, and discounting GWS, Gold Coast and Melbourne. Given that North, Richmond and the Bulldogs are all on 16 points, let's take our cutoff as 13th spot where the Dogs sit. This graph shows the variations in winning percentages and for/against percentages across the top 13 AFL teams after Round 9 for every season since 2003:

Alright now the 2012 ladder is looking more even, particularly compared to 2011, although not as even as 2003 and 2007. Though maybe if you just took the results of the top 13 teams against each other (that is, exclude results involving the bottom teams), it might come out as the most even.

To put the point another way, consider this. This is the AFL ladder after Round 9 this season:

WC	9	32	142.6
ES	9	32	140.2
AD	9	28	127.4
CW	9	28	110.9
SY	9	24	130.7
CA	9	24	128.9
SK	9	20	118.8
HW	9	20	116.4
GE	9	20	103.7
FR	9	20	95.5
NM	9	16	112.7
RI	9	16	110.6
WB	9	16	93.2
BL	9	12	87.7
PA	9	12	86.7
GW	9	4	47.3
GC	9	0	60.2
ME	9	0	51.8

And this was the AFL ladder after Round 9 in 2003:

BL	9	30	124.6
WC	9	28	130
PA	9	24	119.5
FR	9	24	113.7
RI	9	24	107.9
AD	9	20	117.9
SY	9	20	107.2
CW	9	20	105.1
KA	9	18	93.4
ES	9	16	99.8
SK	9	16	84.7
ME	9	12	87.7
HW	9	12	84.1
CA	9	12	81
GE	9	8	84
WB	9	4	82.4

Which ladder looks the more even to you?

What Has Happened To West Coast?

As noted in this week’s AFL Power Rankings, at the start of 2011 West Coast were considered the worst team in the competition. But in a bit over a year the very same rankings show them to the best team in the competition, and they sit on top of the AFL ladder.

How have the Eagles become so good so quickly? A few weeks back I looked at the reasons for Collingwood’s drop off in form, using average Champion Data (SuperCoach) player ratings for their main 22 players in 2011 and 2012. I found then that the reason for the Pies’ relatively cold streak appeared to be mainly due to injuries, and conjectured that they would get better as players returned.

For the Eagles though the reasons for their improvement are more multi-faceted than this. In 2010, when they finished last, a lot of things went wrong for them. Since then a lot of things have gone right. Let’s start by looking at the average player ratings for their main 22 players in each of 2010 and 2011.  

	Supercoach Average
	2010	2011	Diff.
Dean Cox	88.00	116.68	28.68
Nic Naitanui	71.18	94.61	23.43
Josh Kennedy	67.14	84.96	17.82
Scott Selwood	64.90	82.64	17.74
Quinten Lynch	64.57	80.50	15.93
Matt Rosa	79.40	86.89	7.49
Will Schofield	53.05	58.74	5.69
Matt Priddis	108.79	113.16	4.37
Andrew Embley	86.70	90.46	3.76
Mark Lecras	82.19	83.50	1.31
Patrick McGinnity	58.06	57.26	-0.80
Shannon Hurn	84.60	82.48	-2.12
Brad Ebert	70.55	62.95	-7.60
Adam Selwood	91.62	63.16	-28.46
Beau Waters	82.14
Ashton Hams	72.45
Andrew Strijk	65.20
Eric MacKenzie	64.22
Brad Sheppard	59.93
Mitch Brown	57.54
Tom Swift	56.23
Chris Masten	50.23
Luke Shuey		93.92
Daniel Kerr		92.56
Sam Butler		81.92
Mark Nicoski		71.60
Jack Darling		70.91
Andrew Gaff		63.65
Ashley Smith		62.56
Darren Glass		54.46
Changed players	507.94	591.58	83.64
Total	1578.69	1749.57	170.88

A couple of points to note: first, the Eagles had a lot of injuries in 2010. Picking their main 22 was a tough task, but in both 2010 and 2011 I’ve picked the 22 players who played the most games, even though Andrew Strijk gets into the Eagles’ main 22 in 2010 with just 10 games. Second, I think that Champion Data adjusted their formulas between 2010 and 2011 so that ruckmen were rated more highly, so keep this mind when looking at the scores of Dean Cox and Nic Naitinui.

That said, these seem to be the main reasons why the Eagles improved so much from 2010 to 2011:

·        Of the players who were 'core' in both 2010 and 2011, there was a significant improvement in production in 2011 by Cox, Scott Selwood, Josh Kennedy, Naitanui, and Quinten Lynch. Lynch was hampered by injury in 2010, and even though Cox played every game in 2010 it was clear at the time he was hampered too. The other three players are all very young, so it is not too big a surprise to see that they improved.

·        Apart from Cox and Lynch, Daniel Kerr, Sam Butler, Mark Nicoski and Darren Glass also suffered from injuries in 2010, and their return in 2011 seemed to help the side. By ‘help the side’ I mean one could say that they were better than the players they replaced (although in the case of a key defender like Glass it’s hard to tell this from the ratings).

·        The new players in West Coast’s main 22 were all useful additions: namely Luke Shuey, Andrew Gaff and Jack Darling (particularly Shuey).

The Eagles have maintained their form, and possibly improved, in 2012. Let’s see how the 2012 team compares with that 2010 campaign:

	Supercoach Average
	2010	2012	Diff.
Scott Selwood	64.90	110.89	45.99
Chris Masten	50.23	91.44	41.21
Nic Naitanui	71.18	105.43	34.25
Beau Waters	82.14	102.22	20.08
Dean Cox	88.00	107.44	19.44
Will Schofield	53.05	69.14	16.09
Matt Rosa	79.40	94.12	14.72
Eric MacKenzie	64.22	76.38	12.16
Shannon Hurn	84.60	95.78	11.18
Quinten Lynch	64.57	66.44	1.87
Ashton Hams	72.45	69.33	-3.12
Josh Kennedy	67.14	61.20	-5.94
Matt Priddis	108.79	94.71	-14.08
Patrick McGinnity	58.06	43.33	-14.73
Adam Selwood	91.62	53.38	-38.24
Andrew Embley	86.70
Mark Lecras	82.19
Brad Ebert	70.55
Andrew Strijk	65.20
Brad Sheppard	59.93
Mitch Brown	57.54
Tom Swift	56.23
Luke Shuey		110.67
Andrew Gaff		93.89
Josh Hill		79.11
Daniel Kerr		77.33
Jack Darling		76.78
Darren Glass		68.12
Sam Butler		67.20
Changed players	478.34	573.10	94.76
Total	1578.69	1814.33	235.64

Again, the return of some senior players (Cox, Kerr, Glass) to full health has helped, and the new additions (Shuey, Gaff, Darling) have been even better in 2012. Part of the story though may be a natural maturation of players: some players that are now reaching their mid-20s (Beau Waters, Will Schofield, Matt Rosa, Eric MacKenzie, Shannon Hurn) all seem to have improved somewhat, and some players that are now in their early-20s — Selwood, Naitanui, and Chris Masten — appear to have improved dramatically. Or maybe coach John Worsfold has just picked up his game in getting this team to perform! Either way, given that most of this team is still quite young, we could see some more improvement yet.

The Finger Points Outwards - No. 41: Eurovision Bloc Voting

On watching the Eurovision Song Contest, I again wondered if someone had tried to prove or disprove whether "bloc voting" takes place. Sure enough they have, and the results accord fairly well with my expectations. That is, bloc voting did start to pick up in the '90s, and gather momentum into the new millennium. Also, that bloc voting may affect who the eventual winner is, but only rarely. Certainly it didn't seem to affect it in 2012!

AFL Power Rankings: Round 9 2012

And the big guns keep crumbling... Hawthorn's second 'shocker' for the year - a huge loss against the Tigers - sees them fall from the top spot. The new #1 is West Coast; an amazing result given that they begun last year at the bottom of the table.

In contrast to 2011, we may well see quite a bit of shuffling over the next few weeks in what is shaping up as an even season. All of the top ten are just two or three big wins from grabbing the #1 rank, making it harder to gauge just who is the best team out there.

1 (3) West Coast 23.1 (21.7)
2 (2) Geelong 22.2 (23.8)
3 (1) Hawthorn 19.6 (27.4)
4 (4) Collingwood 18.9 (18.0)
5 (5) Carlton 15.6 (14.7)
6 (7) St. Kilda 14.9 (13.0)
7 (6) Sydney 13.2 (14.3)
8 (8) Essendon 10.8 (7.6)
9 (11) Richmond 8.0 (-1.2)
10 (9) Adelaide 6.7 (7.1)
11 (10) North Melbourne 2.4 (3.3)
12 (12) Western Bulldogs -4.8 (-6.6)
13 (13) Fremantle -12.0 (-11.0)
14 (14) Brisbane -14.7 (-17.0)
15 (15) Port Adelaide -28.4 (-33.3)
16 (16) Melbourne -40.2 (-40.3)
17 (17) Gold Coast -54.4 (-50.6)
18 (18) Greater Western Sydney -56.2 (-53.8)

AFL Power Rankings: Round 8 2012

The big mover this week - in the wrong direction - is Carlton, who crash from second to fifth after their big defeat in Melbourne to the Crows. Adelaide, meanwhile, have shot from thirteenth to ninth in the past two weeks with two great wins.

1 (1) Hawthorn 27.4 (28.3)
2 (3) Geelong 23.8 (25.3)
3 (4) West Coast 21.7 (20.6)
4 (5) Collingwood 18.0 (16.1)
5 (2) Carlton 14.7 (25.4)
6 (7) Sydney 14.3 (9.7)
7 (6) St. Kilda 13.0 (14.6)
8 (8) Essendon 7.6 (6.9)
9 (11) Adelaide 7.1 (-3.9)
10 (9) North Melbourne 3.3 (6.0)
11 (10) Richmond -1.2 (0.8)
12 (12) Western Bulldogs -6.6 (-5.7)
13 (13) Fremantle -11.0 (-10.5)
14 (14) Brisbane -17.0 (-19.9)
15 (15) Port Adelaide -33.3 (-36.4)
16 (16) Melbourne -40.3 (-36.6)
17 (18) Gold Coast -50.6 (-51.2)
18 (17) Greater Western Sydney -53.8 (-50.3)