Premier League Post Mortem: The Defenses

Last week I posted the Offensive SRS ratings for the Premier League.  Today we will review the defenses.



Home Defensive SRS
Team	HGA	SOS	SRS
Manchester City	0.632	1.193	0.561
Manchester United	0.632	1.184	0.553
Chelsea	0.684	1.178	0.494
Liverpool	0.737	1.199	0.462
Arsenal	0.789	1.146	0.357
Blackburn Rovers	0.842	1.187	0.345
Stoke City	0.947	1.208	0.260
Aston Villa	1.000	1.184	0.184
Tottenham Hotspur	1.000	1.175	0.175
Birmingham City	1.158	1.187	0.029
Fulham	1.211	1.181	-0.029
Everton	1.211	1.178	-0.032
Bolton Wanderers	1.263	1.181	-0.082
Newcastle United	1.421	1.181	-0.240
Sunderland	1.421	1.167	-0.254
Wolverhampton Wanderers	1.579	1.170	-0.409
West Bromwich Albion	1.579	1.140	-0.439
West Ham United	1.632	1.158	-0.474
Wigan Athletic	1.789	1.152	-0.637
Blackpool	1.947	1.123	-0.825

Manchester is a tough town to score in with both City and United tying for the fewest home goals allowed.  City played a slightly tougher schedule so they get the nod as having the best defense at home.  Their rating of 0.561 is equivalent to about 11 fewer goals (19 x 0.561) than an average team would have allowed.  Overall their offense was only slightly above average so we have to give credit to their defense for carrying them into a 3rd place finish and a group spot in next season's Champions League.

Bottom of this table is Blackpool with a horrendous -0.825 rating.  They managed to allow more goals at home than any other team despite playing the lowest scoring offenses overall.  The additional 0.825 goals they allowed relative to their competition is equivalent to 16 goals over the course of the season.  This is why they deserved relegation.  Even a slight reduction in home goals allowed would have allowed them to earn enough points to avoid that fate.



Away Defensive SRS
Team	AGA	SOS	SRS
Fulham	1.053	1.658	0.605
Chelsea	1.053	1.632	0.579
Manchester City	1.105	1.643	0.538
Everton	1.158	1.649	0.491
Manchester United	1.316	1.588	0.272
Wigan Athletic	1.421	1.661	0.240
Tottenham Hotspur	1.421	1.637	0.216
Arsenal	1.474	1.626	0.152
Sunderland	1.526	1.646	0.120
Stoke City	1.579	1.626	0.047
Liverpool	1.579	1.608	0.029
Newcastle United	1.579	1.596	0.018
Bolton Wanderers	1.684	1.611	-0.073
Birmingham City	1.895	1.643	-0.251
Wolverhampton Wanderers	1.895	1.611	-0.284
West Ham United	2.053	1.620	-0.433
Aston Villa	2.105	1.611	-0.494
Blackpool	2.158	1.596	-0.561
West Bromwich Albion	2.158	1.596	-0.561
Blackburn Rovers	2.263	1.614	-0.649

Fulham and Chelsea tied for fewest goals allowed in away matches.  Fulham's tougher schedule means that they had the best defense on the road.  The Cottagers were one of three teams (Everton and Wigan the others) to allow fewer goals away than at home.  Unfortunately their excellent defense was offset by a sub par offense which prevented them from earning some valuable points on the road.

Blackburn brought up the rear in away goals allowed.  They allowed 43 on the road versus only 16 at home which is the largest differential in the league.  They were pretty successful at home and this saved them from relegation.



Total Defensive SRS
Team	GA	SOS	SRS
Manchester City	0.868	1.418	0.550
Chelsea	0.868	1.405	0.537
Manchester United	0.974	1.386	0.412
Fulham	1.132	1.420	0.288
Arsenal	1.132	1.386	0.254
Liverpool	1.158	1.404	0.246
Everton	1.184	1.414	0.230
Tottenham Hotspur	1.211	1.406	0.196
Stoke City	1.263	1.417	0.154
Sunderland	1.474	1.406	-0.067
Bolton Wanderers	1.474	1.396	-0.077
Newcastle United	1.500	1.389	-0.111
Birmingham City	1.526	1.415	-0.111
Blackburn Rovers	1.553	1.401	-0.152
Aston Villa	1.553	1.398	-0.155
Wigan Athletic	1.605	1.406	-0.199
Wolverhampton Wanderers	1.737	1.390	-0.346
West Ham United	1.842	1.389	-0.453
West Bromwich Albion	1.868	1.368	-0.500
Blackpool	2.053	1.360	-0.693

Manchester City and Chelsea tied for fewest goals allowed but Man City gets the award for best defensive team by accomplishing this record against a tougher schedule.  Blackpool gets the sack.  Despite playing the easiest schedule of opposing offenses they managed to be the only team in the league to allow over two gaols per match.  They're back where they belong in the Championship next season.

Impact of Relegation from Premier League to Championship

Last week I posted about the promotion of teams from the Championship to the Premier League and how playing at a higher level will impact the stats of those teams.  Now I will take a look at the teams relegated from the Premier League and how their stats are affected when playing at a lower level.

	Points	GF	GA	% Promoted
Premiership Results/Match	0.85	0.97	1.71
Championship Results/Match	1.56	1.46	1.17	27%
Change	0.70	0.49	-0.54

The newly relegated teams score 0.49 more and allow 0.54 fewer goals per match which is an improvement in net goal differential of 1.03 per match.  Teams that are promoted into the Premier League see their goal differential decrease by 1.15 per match so it appears that moving between these two leagues will have about a ±1.1 goal/match impact on goal differential.


Applying the rate changes from the above table to the results of the 2011 relegated teams will give us the following projections for their Championship performance in 2012:

Club	League	Season	Matches	Points	GF	GA
Birmingham	Premier	2010-11	38	39	37	58
	Championship	2011-12	46	80	67	45
Blackpool		2010-11	38	39	55	78
	Championship	2011-12	46	80	89	70
West Ham United	Premier	2010-11	38	33	43	70
	Championship	2011-12	46	72	75	60

The 80 points that I'm projecting for Birmingham and Blackpool will probably not be enough to earn a Top 2 finish and automatic promotion.  Over the past 19 seasons, the teams that finished in the top 2 in the Championship have averaged 90 points.  The teams that have finished second averaged 86 points.  Only 4 teams out of 38 have earned auto-promotion with 80 or fewer points.  I would expect that all three teams will vie for a playoff spot next season.  The average points earned by teams that were promoted through the playoffs is 76.


I noted above that 27% of teams relegated to the Championship are able to turn around and earn promotion the following season.  The rate at which teams promoted to the Premier get relegated the following season is 47%.  So why would relegated teams that are dropping into a lower-level league be less likely to earn promotion?  I think that there are two factors driving this:

1. There are only two automatic promotion spots in the Championship.  The third spot is contested by the four teams ranked 3rd through 6th.  So that's three additional matches that would have to be played (the last of which has to be a victory) to earn promotion.  These teams are pretty comparable so anything can happen and usually does.
2. The loss in income that results from relegation often forces teams to sell key players to help stay profitable at the lower level.  So as talent level diminishes, the chances of earning promotion also diminish.

My early picks for the two promotion spots in 2012 are Reading and Cardiff City.  I expect that the three relegated teams will be in the playoff mix along with Nottingham Forest.

Impact of Promotion from Championship to Premier League - Part II

Yesterday I posted about the changes in promoted teams' stats in their first season in the Premier League.  On average, newly promoted teams reduce goals scored by 0.55/game, increase goals allowed by 0.60/game and reduce their points earned by 0.81/game.  I now want to apply those rates against the Championship stats of the three promoted teams to estimate how they will fare next season.

First, Queens Park Rangers with 88 pts,  71 goals scored and 32 goals allowed.  They averaged 88/46 or 1.91 points/match.  If we reduce this rate by 0.81 then they would earn 1.11 points/match in the Premier League or 42 points over a 38-game season.  This would most likely guarantee survival as only two teams have been relegated with as many as 42 points (Middlesborough 1997 and West Ham 2003) since the league went to 20 teams in 1996.  Their goal scoring rate would decline from 1.54 to 1.00/game or 38 goals.  Goals allowed would increase from 0.70 to 1.30 goals/match or 49 goals for the season.  The table below summarizes each team's projected results:

 

Club	League	Season	Matches	Points	GF	GA
Queens Park Rangers	Championship	2010-11	46	88	71	32
	Premier	2011-12	38	42	38	49
Norwich City	Championship	2010-11	46	84	83	58
	Premier	2011-12	38	39	48	71
Swansea City	Championship	2010-11	46	80	69	43
	Premier	2011-12	38	35	36	58

So I would expect QPR to survive.  The odds for Norwich and Swansea are not as good.  40 points is generally considered the safety threshold, but teams have survived with as little as 34 points (West Brom 2005).  Norwich has a decent chance of avoiding relegation at 39 points but I can't see Swansea  also surviving at 35 points.  Only in 2001 did all three promoted teams avoid relegation.  So my prediction is that QPR will survive, Norwich has a 50/50 chance and Swansea will be relegated.