The Value of an Away Goal In Madrid.

The Champions League returns from a winter break with the first round of the much anticipated knockout ties beginning this week. The recent domination of the competition by the richest and most powerful European countries is again reflected in the make up of the draw of the last sixteen. Traditionally the competition has fallen to sides from either Spain, England, Germany or Italy. You have to go back to 2003/04 to find a winner, Porto, which didn't play in one of the big four leagues, followed by a similar gap to 1994-95 when Ajax lifted the trophy for Holland. Indeed, the last eight finals have been exclusively the preserve of this small elite, with eight finalists coming from England, three each from Spain and Italy and two from Germany.

This year, 11 of the 16 survivors from the pre Christmas group stages hail from either Spain, England, Italy or Germany. It is therefore a simple task to pick out the three outstanding ties of the round, as clubs from the big four countries meet head to head. Arsenal v Bayern Munich and AC Milan v Barcelona should provide a great two legged spectacle, but much of the focus will fall on the meeting of Real Madrid and Manchester United, Ronaldo verses Rooney and Ferguson verses Mourinho. Both sides have enjoyed impressive performances in Europe's premier club competition over the last two decades. Madrid's three titles eclipses United's two, but the English side has seen much more success in the last ten seasons, winning the trophy and appearing as beaten finalists, while their rivals on Wednesday night have constantly failed to progress through the knockout phases.

Recent history notwithstanding, Real Madrid are favoured to progress from the tie. They are given about a 60% chance of qualifying for the last eight and their quality is also reflected in the overall tournament odds. They have a 17% chance of being crowned kings of Europe, behind tournament favouites, Barcelona, but well in front of their immediate opponents, Manchester United, the bookmakers fifth best choice with little more than a 7% chance.

The format of a competition can often influence the likelihood of the best sides ultimately succeeding. A prolonged group phase based on individual home and away games, where two of the four teams progress virtually ensures that a high proportion of the best sides emerge intact for the knockout stages. Once the group stages start, the two legged nature of the ties also plays towards favouring the stronger teams. However, the treatment of away goals is an often neglected aspect of the Champions League format and it can have a major impact on the ultimate outcome of a tie.

Chelsea progressed to the final last season with a 3-2 aggregate win against a much more fancied, and some would say more accomplished Barcelona side. But the victory owed much to the clean sheet kept by Chelsea at Stamford Bridge and the away goal scored by Ramires just before half time in Spain. Torres' last second, tie winning goal merely rubber stamped a result that was already assured by the doubling of the away goal already scored in the game.

United find themselves in a less extreme version of Chelsea's match with Barcelona. They are underdogs in the tie, so it is an interesting exercise to see how vigourously Ferguson should try to score one or more away goals and equally how wary Real Madrid should be in case they concede what may appear to be a mere consolation goal, but in the wider context of the tie may prove to be worth much more.

Real Madrid host the first leg and so will be strongly favoured to take a lead to Manchester. However, the current Champions league format applies an away goals rule, whereby away goals count double if the tie is level at full time in the second leg and then again at full time of extra time. So we can use the relative merits of United and Madrid  to compare each teams chances of progressing if Madrid take identical winning margins into the second leg, but do so having conceded differing numbers of away goals.

A simple 1-0 win for Real Madrid, unsurprisingly would make them very strong favourites to progress. A draw of any kind in the return leg at Old Trafford would then be sufficient, as would a win. Defeat by exactly a single goal, provided they scored two or more goals would also see them progress under the away goals rule. Only a repeat of the 1-0 scoreline, only this time in United's favour after 90 minutes would be sufficient to take the game to extra time. Extra time would then give Mourinho's side the option of winning in the extra 30 minute period, drawing the extra time period by a score other than 0-0 and thus progressing again through away goals or if extra time remains scoreless, Ronaldo would have the opportunity to win the game for his side in a penalty shootout.

In short, by keeping a clean sheet on Wednesday night, even if victory is by the narrowest of margins, Real Madrid give themselves a chance of progressing in every scenario where they lose in Manchester by an identical margin to their victory in the Bernabeu.

How A United Away Goal would Alter Madrid's Chances of Qualifying for the Last Eight.

1st Leg Real Madrid Scoreline.	Chance of Real Madrid Progressing.
1-0	78%
2-1	68%
3-2	62%

However should United keep the margin of defeat the same, but manage to grab an away goal, some of the winning margins which would have seen United triumph in the second leg, but be eliminated by an away goal or two are now stacked up to United's advantage. If United lose 2-1 in Spain instead of say 1-0, a 1-0 win at Old Trafford would suffice for Ferguson's side. That scoreline no longer heralds a minimum of an extra 30 minutes and multiple further opportunities for the second leg visitors.

High scoring encounters make for great entertainment, but they are invariably bad news for the first leg home team in a competition which uses the away goals rule. A cautious approach from the hosts should be expected.

How Different Drawn Scorelines Change the Dynamics of a Two Legged Tie.

1st Leg Real Madrid Scoreline.	Chance of Real Madrid Progressing.
0-0	57%
1-1	46%
2-2	37%

The same pattern is seen in drawn games. A goalless first leg wouldn't be a huge blow to Mourinho because it would mean that any draw after regulation time in Manchester would either prolong the tie or hand outright victory to his side. His side would probably still be favoured to win the tie outright. However, that position quickly deteriorates as the first leg result sees more goals, even though the host aren't beaten. At 2-2 after the first 90 minutes, only the unlikely 3-3 or above stalemates are good enough to see Madrid through after 180 minutes or more of football and all other drawn scorelines either see United through or still very much alive in the tie.

An adventurous approach from the visitors in the first leg often reaps rich reward at the conclusion of the tie.

The Cult Of Passing.

Law 10 of association football is quite straightforward and states that the winner of the match is the team scoring most goals. If both teams score an equal number of goals or no goals are scored, then the game is drawn. There is no mention of extra credit for prolonged bouts of possession or passing. Therefore, although both possession and passing are important descriptive aspects of the game, they are merely a means to an end and that end is scoring a goal.

It has been recognized that possession is much less important than what teams do with that possession. The game winner can easily lose the possession battle and often equality of possession is not reflected on a lopsided final scoreboard.

With the demise of possession, it would appear that passing has now replaced it as the desirable stat of choice.

Few would expect Barcelona to raid the Liberty Stadium in an attempt to prise Leon Britton away from Swansea as a natural replacement for Xavi, but as recently as last week Britton's passing percentage was again being used as evidence of his supremacy in this most unnatural of match ups. Britton does most of his admirable passing a good Dan Biggar conversion away from the goal and conversely, Xavi operates in a much more elevated pitch position. Yet still the comparison between the two persists. Without context, the comparisons are meaningless and with context, the differences between the two players become apparent.

Having confused a creative, central midfielder with one who merely plays the simple pass, often from no deeper than the middle third, passing is now also being further used to characterize whole teams. The best teams, in general tend to pass more often and with greater frequency and these two attributes are highly correlated. If we now plot either passing frequency or efficiency against a measure of success, such as points per game, the case for passing appears complete. The better you pass, the more points per game you win.

The circle is complete. Passing is an admired art form practiced by the elite, they reap the rewards of excelling at the skill, while poor passing sides languish in mid table or worse. The implication is clear, to improve sides must become better passers of the ball. However, as with the repeating Xavi verses Britton standoff, the team passing debate lacks all important context and also suffers in the case of some teams from a confusion of correlation verses causation.

In the previous post I introduced in running success rate, a shortcut to adding context to a single match result. It's an offshoot of season long success rate, where the percentage of wins and half draws replace the arbitrary system of three points for a win and one for a draw. A goalless game sees both teams stalemated for 90 minutes leading to a success rate of 0.5 each ((90/2)/90). In similar vein a team winning 2-1 after conceding early goal and then responding with two late goals would have in running success rates of near zero compared to near one for a side which had an identical 2-1 win, but lead from the first minute to the last.

In running success rate adds information in a single number about the time a team spent either trailing, winning or drawing in a single game and that helps to add context to the stats each team recorded over that game, including passing stats.

If we now plot in running success rates for individual games for each club, as a proxy for the differing game states and scorelines each team experienced against their passing efficiency above or below their normal average in those games, we can start to see how important passing is to each team's ultimate aim of winning league points.

As usual, Stoke are the poster child for atypical behaviour during their time in the EPL and once again they buck the Barcelona driven expectation that passing the ball well should bring expected rewards, because the reverse appears to be true for Stoke. The Potters passed the ball more efficiently in games where their in running success rate was at it's poorest. The expected good passing premium doesn't apply to Stoke and on this occasion it also doesn't apply to others as well. Teams who pass better than they usually do when they are more likely to be in losing positions, indicated by low in running success rates, included from 2011/12, Aston Villa, Sunderland, WBA, Fulham, Newcastle, two of the three relegated sides, QPR and....Swansea.

It's easy to weave a plausible, but at best only half true explanations for this reversal of Barca model, but the assumption that better passing always gets it's reward and the arrow of causation always goes from better passing towards better results would seem to be flawed.

Stoke absorb pressure, then try to get into scoring position with low expectation, long passes. If they get ahead they then try to hold that position by absorbing even more pressure and use long balls as an escape route. So in advantageous game positions their passing efficiency starts low and stays low. If they go behind, they aren't suited or particularly able to pass their way through a now more defensively set up opponent, who are also happy to allow Stoke time on the ball in non threatening areas. Consequently, Stoke see more of the ball than usual in the middle third when their in running success rate is poor, but they are able to rack up higher, but ineffectual passing efficiency rates because of this concession by their opponents. In short, game situation sometimes drives Stoke's passing stats, rather than vice versa.

The Barca passing model doesn't fit Stoke's approach to winning points and it doesn't fit the approach of other teams, including Swansea whose incessant passing would appear to be less effective at breaking down more defensively minded, first scoring opponents. A model relating passing to points is too simplistic to capture the diverse way in which teams attempt to get the best from their available talent. A diversity which Law 10 encourages by making goals the only reckoner.

A Tale Of Three Draws.

This post relates to three games played last mid week, but it also serves the purpose of introducing a way to add context to a single match scoreline, particularly in terms of how long teams are behind, in front or level during a single match. Look out for a (very) quick follow up post.

Football cliche met football myth over the recent series of weekday Premiership matches as various teams relinquished or surrendered that most dangerous of two goal leads. It is certainly rare for a team to fail to see out a two goal advantage and rarer still for three games out of a ten match Premiership schedule to feature such comebacks. But rare events do occur and sometimes they clump together.

Scorers.

1-0, Shawcross, 23'
2-0, Crouch, 48'
2-1, McArthur, 51'
2-2, D Santo, 61'

Scorers.

0-1, Suarez, 5'
0-2, Henderson, 61'
1-2, Giroud, 65'
2-2, Walcott, 67'

Scorers.

0-1, Mata, 45'
0-2, Lampard, 66'
1-2, L Fondre, 87'
2-2, L Fondre, 90+4'

The expected points graphs above, show the magnitude of the task faced by first Wigan, then Arsenal and finally and most improbably, Reading. Chelsea were the strongest favourites of the three teams which took a two goal lead and the lateness of Reading's response meant that their in running expected points total had almost disappeared off the foot of the chart and still remained tiny even after Le Fondre's first strike in the 87th minutes.

Three points for a win compared to just one point for a draw, invariably makes the trailing side appear as "winners", even though the spoils are shared and much of the good work of the teams which scored first is forgotten in the dramatic excitement of the comeback.

Stoke lead Wigan for 42 minutes at the Britannia, Chelsea led Reading for 50 minutes and Liverpool gave their supporters real hope of taking all three points for over an hour. And it will be the supporters of those three teams who probably viewed the final stalemate with most disappointment. We can quantify the in running match situation by crediting the time spent leading to each team and also sharing between opponents the time spent at level terms.

Team.	Time Spent Leading.	Time Spent Drawing.	In Running Success Rate.
Stoke v	42'	55'	0.72
Wigan.	0	55'	0.28
Arsenal v	0	32'	0.16
Liverpool.	65'	32'	0.84
Reading v	0	47'	0.24
Chelsea.	50'	47'	0.75

Liverpool had the highest "in running" success rate at 0.84, so the draw and the loss of two points at full time was probably more keenly felt on Mersyside than in the Potteries, where Stoke only lead for 42' in recording a success rate of 0.72.

It is tempting to consider drawn games as evenly fought contests, where the spoils are rightfully shared. But as these three rather extreme example show, often one team holds the advantage for a considerable portion of the game. Match situation can often determine how sides approach the remainder of the contest and this can have implications for stats, such as where and how effectively teams make their passes. In a follow up post, I'll use in running success rates for individual matches to see if such figures can help us to better understand pass completion rates and help to explain why trailing sides sometimes become much better at passing the ball.