Women's UK derby chart, 17-Sept-2012

In the weekly chart that follows:

• Only bouts with public scores between rankable teams within the last 12 months are counted for this chart.  As mentioned before, every other sport's ranking scheme has an expiry date for results, and it's time for derby to have the same.
• Only teams from regular bouting UK and Ireland leagues are eligible for ranking.  Due to the sheer number of leagues, I had to exclude continental Europe from the chart.
• A team with fewer than 2 rankable bouts is excluded from the chart.  As well, a team that has only played bouts against unrankable teams is excluded from the chart.  Both are due to the need for viable data.
• Arrows represent change from the previous week's ranking.  ⇏ indicates a previously unrankable team's début on the chart.  For the sake of this, I ran the rankings for the 10th of September as well.

Rank			Team	Rank Pts	Bouts	W	L
-	-	1	London Rollergirls	157.3	2	2	0
-	-	2	London Rollergirls-B	133.1	3	3	0
-	-	3	Glasgow Roller Girls	103.9	7	6	1
-	-	4	Leeds Roller Dolls	102.1	7	4	3
-	-	5	Central City Rollergirls	92.2	7	6	1
-	-	6	Auld Reekie Roller Girls	90.2	10	3	7
-	-	7	London Rockin' Rollers	88.6	9	6	3
-	-	8	Rainy City Roller Girls	72.6	6	3	3
⇑	1	9	Tiger Bay Brawlers	49.6	8	6	2
⇓	1	10	Big Bucks High Rollers	48.3	6	3	3
-	-	11	Sheffield Steel Roller Girls	41.6	7	2	5
-	-	12	Brighton Rockers	37.6	5	5	0
-	-	13	Hellfire Harlots	36.8	9	7	2
⇑	1	14	Middlesbrough Milk Rollers	33.4	7	5	2
⇓	1	15	Birmingham Blitz Dames	32.8	7	3	4
-	-	16	Hot Wheels Roller Derby	32.1	9	5	4
⇑	1	17	Lincolnshire Bombers	28.2	9	2	7
⇓	1	18	Dublin Roller Girls	27.2	9	6	3
⇑	2	19	Newcastle Roller Girls	25.1	8	5	3
⇑	2	20	Glasgow Roller Girls-B	24.1	8	6	2
⇓	1	21	Dolly Rockit Rollers	22.2	14	8	6
⇓	3	22	Royal Windsor Roller Girls	21.8	5	3	2
⇑	1	23	Croydon Roller Derby	18.7	7	4	3
	⇏	24	South West Angels of Terror	18.5	2	2	0
⇑	2	25	Leeds Roller Dolls-B	18.2	5	2	3
⇓	3	26	Severn Roller Torrent	18.1	4	1	3
⇓	2	27	London Rollergirls-C	17.4	3	1	2
-	-	28	Central City Rollergirls-B	16.5	5	2	3
⇓	3	29	London Rockin' Rollers-B	15.9	3	0	3
-	-	30	Cork City Firebirds	15.0	2	0	2
-	-	31	Manchester Roller Derby	13.8	12	6	6
⇑	1	32	Auld Reekie Roller Girls-B	12.2	5	2	3
⇓	1	33	Granite City Roller Girls	12.2	5	1	4
-	-	34	Bristol Harbour Harlots	11.4	11	6	5
⇑	3	35	Kent Rollergirls	11.4	4	2	2
⇓	7	36	Rainy City Roller Girls-B	11.0	5	3	2
-	-	37	Bedfordshire Roller Girls	10.7	4	2	2
⇓	3	38	Liverpool Roller Birds	10.6	7	1	6
⇓	3	39	Dundee Roller Girls	10.1	5	4	1
⇓	1	40	Cardiff Roller Collective	8.5	8	7	1
-	-	41	Tiger Bay Brawlers-B	7.2	6	3	3
⇓	2	42	Romsey Town Rollerbillies	6.4	7	2	5
⇓	1	43	Impostors Roller Girls	5.4	3	2	1
-	-	44	Seaside Sirens Roller Girls	5.2	5	2	3
⇓	2	45	Plymouth City Rollers	5.2	4	1	3
⇓	1	46	Sheffield Steel Roller Girls-B	4.8	8	3	5
-	-	47	Swansea City Slayers	4.7	7	3	4
⇓	2	48	Rebellion Roller Derby	4.5	5	4	1
-	-	49	Dolly Rockit Rollers-B	4.0	4	3	1
⇑	1	50	Belfast Roller Derby	3.6	6	2	4
⇓	1	51	Oxford Roller Derby	3.5	7	3	4
-	-	52	Dublin Roller Girls-B	3.3	2	1	1
⇓	5	53	Milton Keynes Concrete Cows	3.3	3	3	0
⇓	1	54	Lincolnshire Bombers-B	3.2	5	1	4
⇓	1	55	Wakey Wheeled Cats	3.2	6	2	4
⇓	1	56	Newcastle Roller Girls-B	2.7	6	5	1
⇑	1	57	Fair City Rollers	2.0	5	0	5
⇓	2	58	Hell's Belles Roller Girls	1.9	3	0	3
⇓	2	59	Vendetta Vixens	1.8	4	0	4
	⇏	60	Nottingham Roller Girls	1.4	2	0	2
-	-	61	Hulls Angels Roller Derby	1.3	3	0	3
⇓	2	62	Wolverhampton Honour Rollers	1.3	2	1	1
-	-	63	Fierce Valley Roller Girls	1.2	2	0	2
⇓	2	64	Norfolk Brawds	1.1	2	0	2
⇓	6	65	Furness Firecrackers	1.0	3	0	3
⇓	1	66	Limerick Roller Girls	0.9	2	0	2
⇓	1	67	Liverpool Roller Birds-B	0.7	2	1	1
⇓	4	68	Shoetown Slayers	0.5	3	0	3
	⇏	69	Evolution Rollergirls	0.4	2	1	1
⇓	3	70	Manchester Roller Derby-B	0.3	3	1	2
	⇏	71	Central City Rollergirls-C	0.1	2	2	0
	⇏	72	Wirral Whipiteres	0.0	2	0	2

Rank points are fundamentally dimensionless.  They are not an expected score value, although an expected score can be calculated using them.  More on this later.  

As well, no teams have the same number of rank points.  For the purposes of the ease of reading the chart, they're rounded to 1 decimal place, but no two teams have the exact same value.

Some teams may move up or down, despite not bouting.  This can be do to an old bout expiring, or to associated teams winning or losing strongly.  Similar to the National Rankings I did, these are based on an S_s value.  Thus, if X beats Y, and Y then goes on to beat everybody, X will look better for having beaten them.

I hope this chart proves interesting.  Roll on!

[Edit: Brighton was mistakenly entered as beating Dublin-B, not Dublin.  Mistake corrected.]