BBC vs MSN: But This Year’s Clearly Different, Right?

In last January’s post, I subjected the goal-scoring performances of Barça’s trident and Real Madrid’s BBC to a comparative analysis. I showed that even though Messi, Neymar and Suárez overall turned out to be more efficient than Cristiano, Benzema and Bale, the constituent members of BBC do actually turn out to make each other better (synergistic), whereas Barça’s trident members rather seem to score more often when some of their strike partners are absent (cannibalistic). Neymar emerged as the most pivotal member of Barça’s trident. This analysis encompassed data from the start of both tridents being united at their respective clubs. Now that the 2015-2016 season is nearing a conclusion, it will also be important to investigate what the relations are like for the current season. Perhaps Barça’s trident is already combining much better than before? Let’s revisit the results for the current season only, including both La Liga and Champions League, to date.

We may recall that for the aggregated data, there was only one member of the two trios who was actually more productive when part of his threesome than when not: Cristiano Ronaldo. When looking at the current season, it turns out that all of BBC’s strike partners are more efficient when playing together than when not, whereas no member of Barça’s trident is finding the net more easily when MSN is complete than when not.

Fig. 1: Goal-scoring performance as part of trident (bar) relative to when not part of trident (100%-line)

As can be seen in Fig. 1, the numbers are most extreme for Neymar and for Bale. During 90 minutes on the field with both Messi and Suárez, Neymar scored, on average, 0.4 penalty-adjusted goals. When not part of the trident, in contrast, the captain of the Brazilian national team managed to score slightly more than 1 goal per 90 minutes. Neymar already played for over 1,000 minutes for Barça as not part of the trident this season and almost 2,000 as part of the trident. So even though the numbers for the current season alone are naturally more sensitive than the aggregated ones, there is a solid basis for comparison.

The scoring numbers for Gareth Bale are almost mirror images of Neymar’s. When not part of BBC, the Welshman scored slightly more than half a field goal so far during 90 mins; when part of BBC, 1.2 goals per 90 mins on average. This season so far, Bale has thus been more than twice as productive when part of BBC than when not and his bar in Fig. 1 actually extends beyond what is shown. Bale has been out injured quite a bit though and so there is less performance data on him than would be desirable. Still, he already played in over 800 minutes as part of the BBC constellation and in almost 700 as not part thereof.

So the synergism of BBC vs. the cannibalism of MSN turns out to be all the more true for the current season. Whereas BBC appear to be setting each other up to score more and more, Barça’s trident is not – yet(?) – showing any signs of such improvement. We may well recall from the January post that findings regarding BBC’s synergism and MSN’s cannibalism where quite much lessoned though by the fact that the constituent members of MSN combined were still more efficient than the ones of BBC combined. Let’s see if this still holds true for the current season. Turns out it does not! So far, the sum of the average number of goals scored by Messi, Neymar and Suárez during 90 minutes this season is 2.5, compared to 3 for the sum of BBC’s members. Furthermore, 90 minutes of actually fielding MSN together so far resulted in 2.1 goals, per 90 minutes, vs. 3.5 goals in the case of BBC.

Why then, one naturally wonders, are Barça already this season's uncrowned La Liga champion, with the merengues lagging ten points behind? Although both teams scored and conceded about equally in the league, the scoring data support a twofold answer. First, whereas the above analysis focused only on efficiency, i.e. the average number of (penalty-adjusted) goals per 90 minutes, naturally, efficacy, i.e. the actual total number of (penalty-adjusted) goals scored, is also crucial. Concretely, both Benzema and Bale have been injured quite some time, making that the members of BBC have played slightly short of a combined 7,000 minutes so far this season, in La Liga and Champions League together. Suárez, Neymar and Messi already have more than 8,500 minutes on their combined season’s teller. The efficacy of those three combined is actually higher than the one of Cristiano, Benzema and Bale combined: 78.5 penalty-adjusted goals vs. 76.

Second, the crux to understanding the differential in terms of team outcomes is "goal importance", a measure of how many incremental points one’s goals actually provide to one’s team. Cristiano, for instance, is the undisputed top scorer so far, with 37 penalty-adjusted goals. Suárez has 31, six less. Yet, Suárez’ goals often led Barça to take the lead and/or to win a game, whereas more than a few of Cristiano's goals didn’t actually result in Real Madrid gaining any more points from matches (e.g. neither of Cristiano’s four goals against both Malmö or Celta mattered). The total number of point increments for Barça as a direct result of goals scored by its trident members this season to date amounts to 48.5, compared to 37.5 in the case of Real Madrid (Benzema’s 24 penalty-adjusted goals actually yielded hist team more points so far than did Cristiano’s 37). This underlines the added value of a multi-measure analysis when it comes to top scorers, which has been the subject of a number of earlier posts in this blog, also detailing the goal-importance measure.

Let us conclude the analysis by looking at which player is most pivotal in the blaugrana's scoring as a team. I propose to do this by comparing how often a team (not just the trident) scores with and without a player on the field (a similar analysis for Real Madrid is prohibited by Cristiano not having been on the field for only a minute).

Fig. 2: Avg. number of Barça goals per game with and without player having been on the pitch

Although Barça turn out to score more often without Suárez on the field, the above discussion on goal importance illustrates why this probably should not be overemphasized. The main insight is that the role of Neymar turns out to be even more critical in the current season than for the aggregated data: with Neymar on the field, Barça managed to score 2.76 goals, vs. 1.89 without the Brazilian. The explanation hereof in light of Neymar being both the least efficacious as well as the least efficient of the three members of MSN? As for the aggregated data, of all possible combinations (i.e. solo, duos, trio), the one in which they were most efficient for both Messi and Suárez has been in combination with Neymar only. The presence of the Brazilian seems to enable his strike partners to score, this season more than ever. Most probably, he is the one who destabilizes the opponent, even more than Messi does, which in turn is what creates goal-scoring opportunities.

Barça’s Trident vs. Real’s BBC: Synergies or Cannibals?

During the past weekend in La Liga, no less than ten goals were scored by Barça’s and Real Madrid’s super trios, divided evenly between both. Moreover, each constituent member – Messi, Neymar and Suárez vs. Bale, Benzema and Cristiano Ronaldo, respectively – got himself on the score sheet.

At first sight, one would have to conclude that both trios work splendidly. Indeed, both teams already collected a Champions League trophy on the back of their respective tridents. But let's have a closer look at last weekend's performances. Both teams played one half with their complete trident and one half with an incomplete one and whereas Real Madrid managed all of their five goals during the half their super trio were united and none during the one they weren’t, Barça only scored two goals – one of which a Messi penalty – during the half with their trident in tact. Additionally, Suárez completed his hat-trick entirely during the half when one of his strike partners – Messi – was no longer fielded. 

The important question arising then is, “Do these players actually make each other better?” Concretely, on average during a 90-minute game, do they score more goals when combined than the sum of the individuals, when not operating in a trident (i.e. are they “synergistic”?) or, instead, are they rather “stealing” each others goals, e.g. by being at the end of assists that otherwise a teammate would have scored (i.e. “cannibalistic”)? 

To answer these questions and to better understand what and if there is actually something meaningful going on in terms of discriminant performances between both tridents, in terms of individual vs. combined performance, we naturally need to consider more data. Thus, in preparation for this post, I collected information about all the goals scored by Bale, Benzema and Cristiano Ronaldo as well as by Messi, Neymar and Suárez since they were united at their respective clubs (seasons ’13-’14 and ’14-’15, respectively) to date and considered what combination had been on the field at the time of scoring. As I do elsewhere, I take into account both La Liga and Champions League games, counting penalties for half a (field) goal. The main findings can be summarized as follows:

Table 1: Comparing efficiency (i.e. avg. number of goals scored
      per 90 mins. on the field) as part and when not part of MSN

Table 2: Comparing efficiency (i.e. avg. number of goals scored
      per 90 mins. on the field) as part and when not part of BBC

As it turns out, only one of the six players, Cristiano Ronaldo, actually scored more goals when part of his trident than when not. Some level of "cannibalism" may be expected, e.g. as penalties and free kicks may fall to a teammate in the absence of strike partners, but the relative performance of Barça's three main strikers when vs. when not combined is quite startling, as depicted in the below graph. The red line indicates each player's respective scoring level (100%) when not part of the trident; each bar indicates the corresponding player's scoring level when part of the trident relative to this line:

Figure 1: Goal-scoring performance as part of trident relative to when not part of trident

It can clearly be seen that Barça's trident's scoring performance falls well short of Messi, Neymar and Suárez' scoring performances as individuals (or duos). In fact, as a trio, MSN, on average, scored 2.14 goals per 90 minutes, whereas the sum of Messi's, Neymar's and Suárez' average scoring performances per 90 minutes, when not part of the trio, adds up to 3.22 - over a full (field) goal more. Moreover, the Barça player least cannibalized by the trident, Messi, is still more negatively affected as compared to Real's most negatively affected player, Bale. Real Madrid's BBC scored, on avg. per 90 minutes, 2.33 goals vs. 2.44 as the sum of the individuals' performances - less than a meaningful difference. 

Is there something going horribly wrong then with Barça's trident relative to BBC? Yes and no. On the one hand, yes, as Barça's individual trident members all appear to be sacrificing a substantial portion of their efficiency when operating as a trident. On the other hand, no, because, in absolute terms, overall, Messi, Neymar and Suárez still scored more goals than Bale, Benzema and Cristiano, on average, per 90 minutes (2.56 vs. 2.36). Thus, it would be harsh to claim the former are underperforming compared to the latter. What does clearly emerge, is that Barça's trident still show ample potential to up their performance if they find ways to create more synergies among the constituent players.

Critical question: now that we know that Barça have been substantially more efficient when not fielding Messi, Neymar and Suárez all together, would it actually help the team to keep one of them on the bench? To assess this, we need to consider the goal-scoring performance of the team as a whole (not just the trident) when fielding the trident and when not. After all, if one is not to field a member of MSN, someone else, e.g. Munir, with his own relative (in)efficiency will take his place. Barça's average number of goals scored per 90 minutes turns out to have been very similar when having fielded and when not having fielded the trident (2.60 vs. 2.63), which leads to yet another question: as the team turned out no less efficient without the trident, could FC Barcelona actually save itself quite some money by selling off either Messi, Neymar or Suárez, without sacrificing team goals? And if so, which one of them? 

Hereto, I repeated the exercise of considering team goals, this time with and without each Messi, Neymar and Suárez, respectively, having been on the field at the time of scoring. The results are depicted in the below graph. The blue bars indicate the average number of team goals per 90 minutes with the corresponding player having been on the field; the red ones, without him having been on the pitch - from the start of the '14-'15 season to date:

Figure 2: Avg. number of Barça goals per game with and without player having been on the pitch

From this, it seems that what Barça don't want to do is sell Neymar: not only did the blaugrana score more goals with the Brazilian on the field than with either the Argentinian or the Uruguayan, but also did Barça, on average, score fewer goals per game without Neymar than without either one of his strike partners. Furthermore, as evidenced by the descriptive statistics listed in Table 1, both Messi and Suárez found their most efficient combination of all possible ones (i.e. trident, duos or alone) in duo with Neymar. One likely explanation would be that Neymar is the one mainly able to unbalance the opponent, which is what creates goal-scoring opportunities for the team.

How Barça’s Treble Will Change the History of Football Tactics

Before turning the page on the 2014/2015 season, let’s have a look at the learning and implications for football tactics of Barça’s treble. At least as significant as the move away from tiki-taka is the adoption of a three-forward format, Barça’s so-called trident (with both moves obviously not being unrelated). In this post, I seek to highlight why, from an evolutionary perspective, the importance of FC Barcelona having managed to win everything with such a system can hardly be overestimated.

Source: financialexpress.com

In what is widely considered the most authoritative book on the history of football formations, in Inverting the Pyramid, Jonathan Wilson brilliantly describes the history of formations as a process in which the pyramid became inverted, i.e. a move from an all-out attacking 2-3-5 in the game's early days to a much more cautious sole-striker formation. In particular following FC Barcelona’s tiki-taka success under Guardiola and Spain’s victory at Euro 2012, some observers as well as coaches, notably Carlos Alberto Parreira, prophesied the winning formation of the future even to be the 4-6-0 – perhaps a final evolutionary step.

Did Luis Enrique, with his trident, then defy the laws of football tactics’ natural evolution? The answer is no. In an attempt to make sense of their environment, people naturally tend to look for patterns and cause-and-effect relationships, also where none exist. As football is a social undertaking, made by men’s thinking and acting, there is no “natural" evolution of which the future can easily be predicted or inferred from what came before. Most analysis is thus ex-post sense-making and assuming current tendencies will amplify in the future. Matthew Whitehouse’s recent book Universality: The Blueprint for Soccer’s New Era reads as a prime example hereof: enlightening in explaining the past; very unlikely to have any predictive power. Luis Enrique did not escape from any inevitable evolutionary path but, rather, realized that – as in any human endeavor – there was an active choice to be made.

For signs of just how powerful and self-fulfilling a formation’s success can be, we need not look far: with Cristiano Ronaldo, Bale and Benzema, Real Madrid have a trident of their own. Furthermore, the most promising formation for Atlético, notorious for their defensive pressing through a 4-4-2, in the upcoming season, seems to combine Jackson Martínez (center), Griezmann and Ferreira Carrasco (both wide) – and it probably won’t take Simeone long to figure out just that.

Source: laacib.net

So, apart from there not being any pre-defined, inescapable evolution in football formations, what is the take-away of Barça’s treble this time? Get three excellent forwards and success will take care of itself? Not quite.

1. There’s no one formation that beats the others (which is obviously not the same as saying that all formations are equally good or that formations don’t matter). A team’s best formation depends on the players you have at your disposal. In case you don’t have three – relative – star attackers, there’s as little point in playing with a “trident” as there is in not fielding all three when you have got them.
2. Provided you have the quality forwards, attacking in numbers can be very effective, especially when playing against a team with a non-adaptive system that does not account for facing numerous attackers. Belgium – Argentina, to which I dedicated the first post in this blog, being a case in point. As much as people like to analyze and philosophize about the beautiful game, you get three points only when you score more goals than the opponent, so scoring goals is a prerequisite to winning.

Whether the “trident” will take the rest of Europe by storm remains to be seen. What already seems certain is that Barça’s recent treble success on the back of its trident has silenced prophesies of there being no more room for strikers in the football of the future. We may now also better understand why it makes little sense to believe in some kind of determinism when it comes to the future of football tactics. In Whitehouse’s words,

Football’s future will be defined thanks to the visionaries and risk takers who seek to try new things and experiment with the game. This is how anything evolves, change through trial and error.

Number 10

At the occasion of this blog’s tenth post, I propose to take stock of the evolution of some of the main issues touched upon so far. I am very much aware that Strategy of Football is not your average entertainment blog and that it rather requires attentiveness on the part of the reader. So as to ensure neither you nor I are wasting our time with mere opinion, let’s revisit some of the main themes discussed. Although, critically, the blog is about analysis rather than prediction, from the analyses, often times predictions – either implicitly or explicitly – naturally flow.

In the inaugural post, I challenged Belgian national coach Wilmots’s tactical savvy. Concretely, I disintegrated the strategy of Belgium in their World Cup quarterfinal against Argentina and constructed a more promising game-plan from the bottom up. Although, most unfortunately, it would be impossible to have the game replayed with the proposed tactical plan in place instead, at least now, 3.5 months after the post, (Belgian) people are slowly waking up to some of the facts underlying my analysis. The most relevant evolution probably being that recently some of the star players of the national team (Hazard, De Bruyne, Courtois) openly started questioning Wilmots’ tactics and thereby his tactical capability. Whereas the general public seemed ready to erect a statue for the national coach after the World Cup, the euphoria – or, better, ignorance – is gradually making place for the realisation that we missed a unique chance to write and witness history. Whereas, still in early October, most Belgians’ heart skipped a beat when it was made public Wilmots had offers other than continuing his mission with the national team, to most of them it would now seem to come as a relief if Eric Gerets were announced to be taking over.

Source: nieuwsblad.be

The second post was published after the second match-day in the Premier League. I explained how Courtois was bound to win the duel with Cech as Chelsea’s number 1 and how – most critically – he had the backing of Mourinho. I encouraged Cech to use the last days of the transfer window to find himself a suitable team as he has the quality to be the undisputed number 1 at virtually any top team in the world – but Chelsea. Recently, Cech pointed out how unhappy he is with his substitute role at Chelsea and wants to move on. He could have saved himself four months of being benched and a whole lot of frustration.

In the same post, I suggested that Real Madrid was unlikely to win any trophies as long as they were to keep their hands above the head of their once star goalkeeper Iker Casillas. While, obviously, no trophies have been handed out yet since, Real is topping the Liga table at the moment as well as its Champions League group. I leave it up to the reader to judge what Casillas’s contribution to Real Madrid’s current success is, but at least I acknowledge to be surprised Casillas is still being given preference over Navas. And while even the ultraconservative Spanish national coach Vicente del Bosque found it in his heart to bench San Iker against Luxembourg, meanwhile, the 33-year old seems to have regained his place in La Roja from de Gea. Casillas himself recently stated he is convinced he has seven more seasons in him, so who am I to challenge that. Time will tell who’s right – and I doubt we will have to wait seven more years to find out.

In ‘The Falcon Has Landed…But Is He Here to Stay?’ I pointed out that UEFA's Financial Fair Play rules, next to being constraining, also seemed to have a curious enabling effect. For the first time in history, teams are given a credible excuse not to pay full transfer fees but rather borrow star players for a year – in which these players essentially can be tried and tested. When the world seemed convinced that what was going on was a mere payment in instalments spread over time, I pointed out that the option element would likely make that underperformers were never to be finally transferred. 

Interestingly, yesterday – and 2.5 months after writing the post – I read a first voice along those lines – and no less than Louis van Gaal's. Following Falcao’s persistent injury problems, and following a week in which Man. U. allegedly paid nearly €1 million in wages to its injured players alone, van Gaal admitted that it was all but sure they will exercise the purchase option on Falcao: “Last year, he was out for a long time with a knee injury. Then it is not necessary to take unnecessary risks”, the Dutchman reportedly said. Whether or not Man. U. will eventually exercise the purchase option on the Colombian or not, the fact that they are considering not to proves exactly the point I was making in the third post. Should Falcao not be a Mancunian anymore next year it won’t take long for van Gaal to receive a "biscuit of own dough" (koekje van eigen deeg) as Chicharito is not all that unlikely to be returning to Manchester himself.

In ‘Munir vs. Neymar: 0-2’, I damped the premature optimism regarding Barça’s new sensational youngster Munir and pointed out that Neymar is – and always will be – a much higher quality player. Let’s have a quick glance at the descriptive statistics of both players. In the league and the Champions League combined, since the publication of the blog post to date, Neymar scored 11 goals and gave 3 assists in 13 appearances. Munir totalled 0 goals and 0 assists in 8 appearances. On average, during this period, Neymar has scored 1 goal per 90 minutes he was on the field; Munir no goal per 334 minutes he was on the field.

Source: theguardian.com

The sixth post, I dedicated to troubled Belgian (former) supertalent El Ghanassy having become a free agent. I’m surprised to see that, two months down the road, he is still without a team. Interestingly, the club that showed most concrete interest in signing him so far was reported – about a week after the post – to have been my own KV Mechelen. They were, however, snubbed by El Ghanassy’s agent. Although I doubt both that my club needs another winger and that they are fit to provide the different types of professional support El Ghanassy would need to succeed, in case they are still interested, it would be well worth informing about him again. Meanwhile, his expectations will likely have been adjusted downwards now that he’s been without an employer – and thus income – for over two months already. Indeed, relegation-threatened Cercle Brugge now seem to be his best available tangible alternative – probably not what he or his manager had in mind at the time of telling KV Mechelen off.

Source: zimbio.com

Of the remaining published posts, only some conveyed ready predictions. Ronaldinho is still in Mexico rather than the MLS, but give the man some time. As for Brendan Rodgers, he, predictably, got burnt playing with fire, his side losing at home against Chelsea, in spite of their relative physical fitness. Still most interesting to see will be whether at least Rodgers can salvage a Champions League qualification for his Reds in the remaining two matches, having forfeited 3 potential points against Real Madrid, in the advent of the Chelsea game.

To conclude and look ahead, do note that at the bottom of every post there is a possibility to comment: for any substantive matters, feel free to do so, as we all stand to learn!

Nothing More Important Than the Game After Next?

One of the most promising fixtures of this week's Champions League was at the Santiago Bernabéu, where Real Madrid would be hosting Liverpool. What may have slightly tempered expectations of a great game to come was that Liverpool had lost 0-3 at Anfield. At the same time, the Reds could thus be deemed to be out for revenge. Not so Liverpool’s manager Brendan Rodgers though: he baffled friend and foe by fielding a “B-team” in the most high-profile club competition, against the reigning champion. The rationale: Liverpool would be facing Chelsea in the league on Saturday, a game with a higher expected value for Rodgers. The Champions League qualification, Liverpool would compete for in its final two group games, against lesser opponents. Was this “strategic weakening” of his squad a clever move by Rodgers? I am quite convinced of the contrary and mainly for two reasons.

Source: independent.co.uk

First, the move is demonstrative of no less than two reasoning errors. The first error is to conceive of football as purely – or at least almost exclusively – a physical game, with a team’s performance being determined by the physical fitness of its players. A second and related error is “either/or” thinking, which has little or no solid ground in this case.

Let it be well-understood that physical fitness naturally determines for a great part how a team will perform. Thus, resting one or two players – even star players – in case they are showing clear signs of fatigue, e.g. as was Steven Gerrard ahead of Tuesday’s game – is quite granted. Deliberately weakening one’s team, as by replacing half the squad, is quite a different thing. As a result of the latter, those players who were put to rest – meaning they were not to play in the Bernabéu against Real Madrid, which they may or may not have enjoyed – may indeed be fresher, physically, when comes Saturday’s Chelsea game.

What is more, these players now also know that their coach is so convinced of their skill he is willing to accept defeat against a team such as Real Madrid already beforehand. A team’s manager should also be its leader and thus always the last man standing. Nothing more demoralising for players and fans than a leader who no longer believes in Sepp Herberger’s truism that the ball is round, i.e. that anything can happen on a football field. Furthermore, Liverpool is not just any club. It is the club whose fans are famous for it never having to walk alone. And the club that won the very Champions League in 2005 following the Miracle of Istanbul, recovering from trailing 3-0 at half-time against AC Milan. No miracle in the Bernabéu though. For miracles can only happen if you believe in them.

I like to link this experience to three separate episodes I witnessed in the past, in Belgium. In 2010, SV Roeselare was playing the semi-final of the Belgian Cup, against Cercle Brugge – not the strongest of opponents. Roeselare is a very small team, also for Belgian standards, and they were struggling not to relegate that season. For coach van Wijk it was very clear that remaining in the first league was much more important than playing the cup final – which, otherwise, for fans and players of a team as Roeselare tends to be a once – or never – in-a-life-time experience. And that he would not hesitate to keep his players fresh for the former challenge. Apparently, for van Wijk, it was “either/or”. Roeselare lost the cup’s semi-final first leg with 0-3. And it got relegated to the second division, where they remain up till today. Go to Roeselare and I challenge you to find a fan convinced s/he will ever make it to the King Boudewijn stadium to see his/her club compete in the cup final.

Another eye-opener for me was KV Mechelen’s home game against Club Brugge in the 2013-2014 season. Despite disappointing league positions in recent years, KV Mechelen is a team with a strong home reputation, in part thanks to the proximity of its fanatic supporters. In August ‘13, all signs were pointing to it again being “one of those nights”: with twenty minutes remaining, KVM had recovered from being one goal down and, five minutes after, when a Brugge defender was sent off, was left with ample time to bring the game home.

KV Mechelen's coach at the time, van Veldhoven, had initially approached the game very conservatively, playing with a sole striker. Even with Brugge being one man down and with the momentum of the late equaliser, he did not make any attacking change. As a result, Mechelen’s ample defenders were left so idle and with such a drive forward that they constantly ran out of position, leaving the team most vulnerable on the counterattack. Even playing at home against ten men, the coach did not believe we could beat Brugge that day. This became a self-fulfilling prophecy: we lost after Brugge got a penalty on the counterattack. Even more contagious than a manager’s relentless belief in his/her squad's ability is his/her lack thereof – and more so when it shines through in the tactics.

A more joyful example of contagion: shortly after my team, KV Mechelen, won the European Cup Winners Cup in 1988, by beating Ajax in Straatsburg, they were to receive archrival Anderlecht in the domestic league. After three days of non-stop celebrations, it is generally believed that the state of KV Mechelen’s squad at the time of kick off against Anderlecht is best described as “half-drunk”. KV Mechelen went on to beat Anderlecht 3-0 and the festivities could recommence.

From left to right: Erwin Koeman, Michel Preud'homme,
captain Lei Clijsters, Marc Emmers
Source: stamnummer25.be

Before getting carried away, on to the second reason why Rodgers’ move was in error. A football game is always played against an opponent. Thus, strength, weakness and fitness make most sense when considered relative to the opposition. The game Rodgers was saving his men for was against Chelsea. Chelsea would be playing in the Champions League one day later than Liverpool, away in Slovenia. Following their respective CL matches, Chelsea would have only two days before the league game; Liverpool 3, or 50% more than Chelsea. But then, if Rodgers believes his players could never get a result against Real Madrid, they probably need to be much more rested than Chelsea’s to stand any chance against them.

Let’s see what the physically fresh Liverpool players will do against Chelsea this weekend. And how and if Rodgers will be able to convince his team that the coming games in the Champions League are important – and that they surely have what it takes to win them.

So the Ball Doesn’t Go In by Chance. But Do We also Know Why?

Football leaders who come from a business background generally are met with great scepticism by the wider public and everyday evidence shows this is often deservedly so. The take of Ferran Soriano, CEO of Manchester City FC and former Vice President of FC Barcelona, is an interesting one, though: he warns against readily translating business ideas into a football context and instead extracts from his business background rather the conviction that a thorough understanding of the logic behind a phenomenon – let it be business or football – will allow for improving upon its management. Moreover, to better understand the logic of football, he embraces authoritative research findings in this arena.

As a notable example, in the first chapter of Goal: The Ball Doesn’t Go In by Chance, the now CEO of the Citizens points to findings by researchers Szymanski and Kuypers of a club’s success being strongly positively correlated with how much the club spends on players' wages, but not transfer budgets – a key take-away featured also in Soccernomics, the bestseller co-authored by Szymanski. Two things are striking about Soriano’s account. First, that he seems to get the interpretation of the findings more right than the researchers in question. Secondly, that it appears to be the “common sense” Soriano refers to that helped him get the interpretation more right, but that a true logic for doing so remains hidden. In this post, I will explicate the logic behind a plausible interpretation of these findings. This will also provide a handy checklist for when interpreting research findings more generally.

In Soccernomics, the authors mention that, based on analysis of historical data from the English Premier League, they are able to conclude that, “the correlation [of a team’s league position] with players’ pay [over a long period is] about 90 percent. In short, the more you pay your players in wages, the higher you will finish”. Even more than the content of this claim, what is interesting here, from a scientific perspective, is the leap from one step to the next: the strong positive correlation is suggested to imply a causal relationship of the type “A leads to B” (with "A" being players’ pay and "B" league position). The A->B causal interpretation, however, is only one of at least six possible explanations for the strong positive correlation. I will argue that it is most probably not the applicable one here and that Soriano intuitively rather seems to have gotten the most plausible one. 

Possible explanations for the strong positive correlation include the following:

1.     There is correlation, but no causation. In fact, correlation does not automatically imply causation: some things just happen at the same time, but without one causing the other. For instance, following the Dutch Armada’s recent surprisingly disappointing performances in the Euro 2016 “qualifiers” – let’s more accurately call them “friendlies”, as everyone is to qualify anyway – journalists started speculating, rather jokingly, that the Dutch may be encountering the “curse of the third”. Apparently, since 1980, no country other than Germany that ended third in the preceding World Cup has been able to qualify for the subsequent Euro Championships. People of common sense readily understand that this is just a “funny coincidence”, e.g. similar to England on average being more successful when playing in red than white jerseys. Moreover, the number of data points would be too small to make any rigorous claim to the contrary. Szymanski et al.'s analysis appears to be based on ample data so that this explanation of mere coincidence can comfortably be ruled out.

2.     The strong positive correlation is not due to coincidence and thus indeed points to a causal relationship. In this case, the causal relationship can still be one of at least four types:

• A leads to B. In our example, higher wages directly lead to a better league position, i.e. the explanation proposed by Szymanski et al.

• B leads to A. In our example, a better league position leads to higher wages. Winning a league naturally implies winning prize money, of which the players are to get a significant share. Not all that implausible as an alternative explanation then, perhaps. But note that the proportion of prize money in a typical footballer’s wage tends to be rather small.

• A and B are positively correlated, not because one causes the other, but because they have a common cause (“C”). A typical example would be the one of the use of sunglasses and temperature being strongly positively correlated. Neither one causes the other. Rather, they both have a common cause, viz. intensity of sunlight. In our case, A and B would seem more closely connected than merely through a possible common cause, though.

• What is also possible is that A does lead to B, but only indirectly, i.e. through another variable, viz. a mediator ("D"). In our case, it seems most plausible that paying higher wages (A) leads to a better league position (B), but primarily if not only to the extent that these wages are used to employ better players (D).

So, which one will it be?

Not only do Szymanski et al. seem to incorrectly suggest that correlation automatically implies causation, but also that if there is causation, it must then be of an “A leads to B” nature. To appreciate how unlikely this explanation for the on-hand correlation would be, consider what it actually implies: that if you are to pay more (to whomever), you will obtain a better league position. So if you merely start paying your team’s current players as if they were Messi or Cristiano Ronaldo, your team would soon get the results of Barça or Real Madrid. Szymanski et al. seem at least to acknowledge this inescapable implication of their attribution of their findings and – more puzzlingly – seem to go with it: “The question, then, is...[with] this knowledge of the relative importance of wages and unimportance of transfers, how can you win more matches? ...In general, it may be better to raise the pay of your leading players”. Agreed, paying peanuts is likely to hire you monkeys. But is rewarding your monkeys as if they were stars going to turn them into a dream team, really?

What about Soriano? He, as readily, neglects coincidence, thus equating correlation and causation – though he seems to be ruling out coincidence already in the very title of his book. His interpretation of the findings: “So, if you want…a team with a chance of regularly winning championships, then you need to work consistently to have a big club that generates enough revenues to be able to sign the best football talent available.” So the finding that transfer expenditure does not seem to be strongly positively correlated with sportive success does not fool Soriano into believing that it is your current squad that you should simply start paying more. Interestingly, while he gives the impression he is merely reiterating Szymanski et al.’s conclusion, in fact Soriano is rather endorsing the alternative explanation of a favourable position in the league pre-requiring that high wages are used for attracting top talent.

Where Soriano does err, is in stating that per the analysis and findings by Szymanski et al., common sense has been “corroborated by mathematics”. A subtle, yet meaningful, distinction is to be made here. Szymanski and Kuypers were not using mathematics, but rather statistics and, more specifically, regression analysis. Why is this distinction important? Because mathematics is the only way by which general truths can actually be proven. For instance, that (a + b)² = a² + b² + 2a.b can easily by proven by simple application of algebraic rules. Unless someone is able to spot an error in the mathematical proof, a general rule has thus been proven. Additionally, in the natural sciences, there are several general laws that are derived from observation. An apple falling from a tree, for instance, points to the existence of gravity, which will always apply on the earth’s surface.

It is very different in the social sciences, however, where human will and behavioural traits make that not all priors will necessarily lead to the same outcomes. Regression analysis is here typically used to discern meaningful patterns. Very importantly, though, such analysis cannot prove something to hold generally; it can only show for something to occur, with a certain level of probability (cf. confidence intervals) under certain conditions and controlling for certain factors. (One can prove for something not to hold generally, by means of an empirical counterexample, e.g. if a team of 8 beats a team of 11, it has been proved that this is not impossible. However, the general rule can never be proven (empirically): the fact that so far every time a team of 11 came to beat a team of 7 does not show – let alone prove – that that is what will always happen under such conditions.)

Consequently, in the case of regression analysis, and unlike with mathematics, it is not uncommon for different researchers to be able to show quite contradictory findings, based on similar data, e.g. by accurately vs. not controlling for mediation or a common cause.

In short, when there is strong positive correlation, several things can be going on, including nothing at all (i.e. coincidence); A leading to B; B leading to A; C leading to both A and B; mediation; or strong correlation may disappear when accounting for adequate controls. The "noisy neighbours'" CEO appears intuitively right in his interpretation of the potentially important football findings proposed by Szymanski et al. I would expect him to be first to acknowledge that it is helpful to have made visible the hidden logic of why that is so.