Losing Teams Win More Corners.

It's debatable whether Norwich's home win over Manchester United or Wigan's unlikely victory away to Tottenham has been the upset of the Premier league so far. United and Spurs both had about a 66% chance of winning their respective contests, but a single goal without reply from their opponents was enough to seal their defeats.

Both games and the manner of the wins for the underdogs illustrates why football stands out from so many other sports. Firstly, each game was a relatively large mismatch. Recently promoted Norwich, fourth favourites to be relegated this season entertaining perennial Champions, United and top five Spurs hosting Wigan, fifth favourites for the drop. Yet the chances of a win for the better side in each game was only 2 times in every three, so we wouldn't have to wait too long before an upset win for the underdog or a draw materialised.

Football matches are difficult to win, even when the very best play the not so gifted, and the reason is football's uncompromising approach to scoring. To win you have to score and scoring is a relatively rare event. Even the very best struggle to score more than two goals a game on average and the number of scoring events in a typical EPL game never stretches beyond three.

By contrast sporting competitions such as the NFL not only have a higher rate of primary scoring, an average NFL side will score two touchdowns per game, but it also rewards partial success by allowing teams to move the scoreboard by kicking a field goal. Similarly, rugby allows for tries and penalty kicks or drop goals with a variety of different points totals awarded for each success.

The effect of each NFL team averaging five scoring events per match is to greatly reduce the possibility of a tied game (overtime also kicks in to even further prevent the possibility of a tied game entering the records), but the award of points for showing attacking intent and ability also encourages a favourable outcome for the better team in the game. NFL games where the favourite has a 90+% chance of winning aren't uncommon, whereas Manchester United's near 80% chance of beating rock bottom and under new management QPR is about as one sided as it gets in the EPL.

The different approaches to scoring sees the NFL sacrifice a degree of unpredictability for elevated scoring levels, while the EPL risks appearing dull and low scoring, but increases the likelihood of Norwich type matchups and subsequent upsets appearing more regularly. In short the scoring system in the EPL and world football reduces the skill gap between teams by only rewarding a specific ability, namely the ability to score.

Football's singular approach to scoring is responsible for many of the statistical trends that are observed within matches. A NFL or rugby team can turn territorial advantage readily into points on the scoreboard. Once an NFL side reaches it's opponents 30 yard line, there is around a 70% chance that they will score, split almost equally between a touchdown or a field goal. They've reached a point on the field were they have a high percentage chance of taking three points and the constant set piece nature of the sport ensures that they are almost always afforded that opportunity. Rugby is less clear cut, the semi fluid nature of the sport makes retaining territory likely, but no means guaranteed and banking three points is dependent upon a more difficult, open play drop goal or a penalty transgression by the defending side.

In soccer, there is no secondary prize for gaining territory, additionally maintaining that territory is also more difficult because of the very fluid nature of the sport and the absence of a restraining line of scrimmage as in the NFL or an offside line in rugby. Your opponents are fully at liberty to try to take the ball away from you from all angles. All a soccer team gains from being higher up the pitch is the right to try to create a goal scoring attempt from a more threatening position. Until a goal is scored both teams are still equal, regardless of territory or possession.

What a soccer team does accumulate are the products of attacking their opponent's goal, most notably corners. Corners are successfully defended goal attempts or threatening situations that have been temporarily neutralized and just as deep, but unsuccessful offense in the NFL yields field goals, soccer counts it's corners.....just not on the scoreboard.

Average Number of Corners Won Per Game, EPL 2006/20012.

Team.	Corners Per Game.
Manchester United.	6.7
Arsenal.	6.6
Liverpool.	6.6
Chelsea.	6.5
Aston Villa.	6.2
Spurs.	5.9
Everton.	5.7
Manchester City.	5.4
Portsmouth.	5.4
Bolton.	5.3
WBA.	5.2
Blackburn.	5.2
WHU.	5.2
Middlesbrough.	5.1
Newcastle.	5.1
Birmingham.	4.9
Wigan.	4.8
Stoke.	4.8
Fulham.	4.8
Sunderland.	4.7
Charlton.	4.2

If we average the number of corners won by EPL teams with multiple seasons since 2006 we find that corner do correlate reasonably well to attacking prowess. The better sides, which we would expect to do more overall attacking, such as Manchester United, Chelsea, Liverpool and Arsenal each appear at the top of the table and relegated or lower table, recently promoted sides dominate the foot of the table. Overtly attacking wing play may be able to tweak a sides corner count upwards, but general weight of attacks appears to be the dominant factor.

"Better teams win more corners" is a pleasingly simple and intuitive conclusion, but as with many apparently obvious statements in football this one has issues of causation and context. Below I've plotted the line of best fit for the average number of corners gained by firstly, home sides and then away sides sorted by their pregame chances of winning the match and by whether they actually won or lost the match in reality.

Average Number of Corners Won by Home EPL Sides 2006/2012.

Average Number of Corners Won by Away EPL Sides 2006/2012.

As you would expect better sides as a group, denoted by a higher pregame win probability accumulate more corners. But the conclusion has to be qualified because almost universally teams win more corners in similar matchups when they go onto lose the match compared to when they win it and the disparity is greatest when the gulf in class is at it highest. Massive pregame favourites win an average of six corners when they win, but nearly eight and a half when they lose.

Football teams, especially the best acquire corners as a by product of attacking play and because, unlike other sports, these secondary statistics aren't translated into points, they have to continue to attack until they make the ultimate breakthrough and score. When they trail, the best also have the ability to press their opponent's goal even more and if they spend a large part of the game attacking, but not scoring, they gain even larger numbers of corners. In short if they attack and take the lead, they can alter their tactical approach to be more defensive, leading to less corners than if they continue to attack in a trailing situation.

So counter intuitive as it may seem, higher numbers of match day corners is quite likely to be an indicator of defeat.

Below we can see how the scoring system in football dictates the match outcome. If we treated corners as a secondary scoring method and as a proxy for the amount and depth of attacking undertaken by each side, akin to field goals in the NFL, we can see how soccer might pan out if football rewarded territory and possession as rugby and American Football does. As a fun exercise each goal has been awarded a hybrid six points and three for a corner and as a consequence 11 of the last six year's 20 biggest upsets would probably not have happened and a further three may have ended as draws.

Corner Counts from the EPL's 10 Biggest Upsets, Underdog at Home, 2006/2012.

Home Team.	Away Team.	Home Corners.	Away Corners.	Alternative Home Score.	Alternative Away Score.
Burnley (1)	Man U (0)	1	12	9	36
Wigan (3)	Chelsea (1)	4	7	30	27
M'bro (3)	Chelsea (0)	5	9	33	27
Fulham (1)	Chelsea (0)	0	16	6	48
Stoke (2)	Arsenal (1)	3	5	21	21
Wolves (2)	Man U (1)	4	6	24	24
Bolton (1)	Man U (0)	4	6	18	18
WHU (1)	Man U (0)	1	11	9	33
Fulham (2)	Man U (0)	3	4	21	12
Wolves (1)	Chelsea (0)	4	9	18	27
Average.		2.9	8.5	19	27

Corner Counts from the EPL's 10 Biggest Upsets, Underdog Away, 2006/2012.

Home Team.	Away Team.	Home Corners.	Away Corners.	Alternative Home Score.	Alternative Away Score.
Arsenal (1)	Hull (2)	15	4	51	24
Arsenal (2)	WBA (3)	16	4	60	30
Chelsea (0)	S'land (3)	6	3	18	27
Spurs (0)	Wolves (1)	1	5	3	21
Spurs (0)	Wigan (1)	16	7	48	27
Man U (1)	Man C (2)	8	7	30	33
Man U (1)	B'burn (2)	7	1	27	15
Arsenal (0)	N'castle (1)	12	2	36	12
L'pool (1)	B'pool (2)	5	2	21	18
Arsenal (1)	A Villa (2)	13	2	45	18
Average.		9.9	3.7	34	22.5

Football is a finely balanced process and if it had taken the scoring route favoured by rugby, dynamically it would be a very different sporting contest. Better teams could steadily build up a lead instead of frequently living on the knife edge of a stalemate.

 Equally, every aspect of the game needs to be looked at under the context within which it is measured. As a further illustration that all may not be as it seems, four of the above upsets saw the better team reduced to ten men, but it is likely that the dismissals caused the upset in just two cases. In the other two matches the players were dismissed when the game was effectively lost. So the arrow of causation was likely reversed. Bad discipline begat goals in the Wigan/Chelsea and Fulham/ManU matches, but goals may have begat petulant, bad discipline from the losers in the Stoke/Arsenal and Fulham/Chelsea games.

As with corners, context is essential for to fully interpret almost any football stat and for the record, Manchester United claimed 12 corners in their defeat at Carrow Road last Saturday and Spurs won 9 in defeat to Wigan.