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Premier League vs. Europe: A statistical comparison of defending

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Chelsea and Defence in the Premier League vs. Europe: A statistical analysis

Chelsea v Burnley - Premier League Photo by Michael Regan/Getty Images

This is a continuation on the piece done to evaluate Premier League’s defences between one another, which you can find by clicking here. In this one, we will compare the English league to its European peers looking at shooting conversion numbers, expected goals and where these shots are being taken.

It is good to remind that as posited in the first article of this subject, looking solely at defensive stats such as interceptions, blocks and so forth is far from the best indicator of defensive performance. But shooting, expected goals and conversion numbers do give us a better perspective, even if still limited in this young mix of data analysis and football.

Onwards!

(NB: The shooting and conversion numbers were all taken from Scott WillisTableau page. You can see his xG model here. Said data covers the Big 5 League from their start until February 23rd).

PREMIER LEAGUE

This table has already been used before, but it serves as a reference to when we get to other leagues. The most relevant numbers here are the conversion percentage from total shots and shots on target, as well as the difference between goals against and expected goals from shots on target that are a good indicator of how a goalkeeper perform in shot-stopping tasks. There is also the number of big chances brought and converted to see which defence handles those best.

From those, we can recall that Chelsea do very well with their defence — at least up until the date those statistics were drawn from. We have the third-best conversion rate in the league at 7% below only Burnley and Manchester United, and the second-best rate in expected goals from shots on goals at 18.56 where Manchester City topple us with 16.5. And Chelsea are pretty good in containing and handling big chances against, allowing only 8 of 25 to be converted.

However, the difference between goals suffered and expected goals from shots on target might be indication on the suspicion of some fans that Thibaut Courtois is not performing at his usual self. This may very well be due to fitness problems and even then, he is still well above the 2.10 league average in this category with a 0.44 rate. He still has massive help from his defence, who allow the expected goal rate per shot on target with 0.255. But he is not as much of a difference-maker — at least in pure, unadulterated shot-stopping — as peers such as Burnley’s Nick Pope and Manchester United’s David de Gea.

PL shots zones and headed shots per game

For the graph above, further reading might be required in Michael Caley’s Cartilage Free Captain piece breaking down how shots in certain areas, especially those central and near the goal are more likely to be converted than others such as ones taken from outside the box. Also, in almost every expected goals model — including Scott Willis’ — headed shots are considered bad.

In regards to shots, Chelsea do well even if they are not as effective as league-leaders Manchester City, and our main competitors for a top-four spot Liverpool and Tottenham Hotspur. Perhaps this is not much of a coincidence...

There is also United whom despite not being as solid defensively as many pundits would claim, is being single-handedly saved by De Gea on multiple times.

SERIE A

Looking at the graph above, we can see why Roma goalkeeper Alisson is drawing interest from some of the biggest clubs in the world for his services. The Giallorossi already have a good defence, even if not on par with Juventus and Napoli. And Alisson only raises their level with his great shot-stopping skills that also suit the Brazilian national team very well.

And Napoli, even though they are mostly known for the offensive prowess and heavy focus on possession, are quite good when it comes to defence. Maybe if their coach had a better set of players to work with, he could do some big impact in a scene where things are not as lopsided towards one team as it currently is in Italy at the moment.

Serie A shots zones and headed shots per game

Both Napoli and Juventus are a class above their peers when it comes to defence, getting the best rates in terms of total and headed shots against them and partially highlighting one of the reasons for their ongoing clash over conquering the Serie A title. And Verona, who currently stand at 19th-place, have managed to be the worst in every shooting category, and third-worst in headed shots. Yikes.

LA LIGA

From De Gea to Courtois and a quick transition with Miguel Ángel Moyà before getting Jan Oblak between the goalposts. Atlético Madrid’s competence (and luck) in finding quality goalkeepers is just astonishing!

The beloved club of Diego Costa reign supreme in the defensive stats thanks not only to the work of their stellar goalkeeper, but also their tactical set-up from Diego Simeone’s work. And Barcelona, who have been far from slouches in defence under the guidance of Ernesto Valverde, come second in the stats and first in the league table.

Meanwhile their biggest rival in Real Madrid are just a middle-of-the-pack side not only in general conversion stats but with regards to what they have been able to get from their current goalkeeper Keylor Navas. Which is all taken as unacceptable for a team of their silk, and have them now looking for players such as Courtois to address this issue.

La Liga shots zones and headed shots per game

From what was seen in the shooting conversion graphics, maybe you would expect the best numbers on the board to be posted by Atlético and/or Barcelona. This however falls on a completely different side in Eibar.

Considering the usual ways of Spanish football, Eibar are very conservative in their approach, having scored only 36 goals in 29 matches while averaging 51.3% ball retention. But their discipline wields good results as they currently stand at 11th-place in the league table, and 18 points away from the relegation zone.

And so they are well below the league averages in every “shooting against” statistic. Good on them!

BUNDESLIGA

The German Bundesliga carry the virtue of having only 18 teams in the competition, and thus fewer games played in it. And the (usually) high-octane playing style of their teams make it for one of the most entertaining leagues to follow.

No wonder only 5 of those 18 sides do not have a rate below zero in the goals against to expected goals from shots on target difference (as in having a goalkeeper that allows less goals than expected from the shots he faces). Coincidentally, it is also the only league with a rather significant number of teams with a total expected goals number higher than its shots on goal counterpart with 6 while most leagues have only a couple of clubs in this situation.

As for “individual” highlights, we see how Bayern Munich are still the best in the country even if their goalkeeping department suffered a big loss with Manuel Neuer’s injury. Meanwhile, the team that had been the second-best for a while in Borussia Dortmund need loads of help from their goalkeeper to remain in contention for top places.

Also, Köln goalkeeper and Football Manager perennial promise Timo Horn has done enough (in real life) to show he deserves a better team.

Bundesliga shots zones and headed shots per game

This is not as surprising as La Liga’s graphs, as Bayern topple the charts in most categories. In fact, they are well above the rest of the competition in terms of danger zone shots suffered with 2.62 versus a league average of 5.02 per game. They are also good in the aerial game, allowing only only 1.1 headed shot per match. All in all an expected result from the team that enjoy devouring their domestic competitors in the transfer market.

LIGUE 1

Despite shelling out enough money to buy the entire league, Paris Saint-Germain are not the very best in every defensive stat of the board. Inadmissible!

But overall, their defence still fares quite well which I guess is one of the perks of having world-class centre-backs such as Thiago Silva and Marquinhos playing for you week in and out, as well as being able to play one-sided football against almost all of your opponents in the process.

And in shot-stopping terms the French league as a whole do not fare as well as their neighbours. The highest rates in the goals against minus expected goals from shots on target stat come from Montpellier, Rennes and Toulouse at -3.71, -3.39 and -3.25 respectively. PSG themselves are better than the 1.57 league average, but on a situation similar to Real Madrid where an upgrade in the goalkeeper position would likely take them higher in the ranks.

Ligue 1 shots zones and headed shots per game

In terms of shots allowed Paris Saint-Germain are the best side of the league, with Montpellier closely behind them. But the former also have a stellar offence while the latter are mostly a defensive force.

Monaco, who currently stand second in the league table, are not really in the same standings in defensive terms. Like PSG they have a great offence but their backline falters. Still, it is a remarkable feat that they have been capable of retaining their domestic strength after being almost completely dismantled last summer, and we can expect them to make a good surge once their current technical director gets a chance to handle — or at least have a proper voice — in their market affairs a few months from now.

COMPARISONS BETWEEN LEAGUES

To diminish discrepancies on data between leagues, it is best to take each of its statistics on a per game basis instead of total values. But in case you want the whole package, we have the numbers in the table below.

And here are the numbers we are going to work with.

In the 14 categories listed on the graph above, the Premier League are equal or better than average in only 5 of them. Those are shots against on target (3.94 vs. 4.03 average), shots against on target accuracy (32.66% vs. 33.35%), total expected goals (1.25), expected goals per shot (0.104) and expected goals from shots on target (1.15) — with the last three being values in which we were dead centre between the five leagues under inspection. The English league are also the worst in goals against per game (1.23) and big chance conversion rate (40.92%). Certainly not a good look...

Speaking of positives, Italy seems to be still carrying their tradition of solid defences and so forth, being the best league in 6 of the most meaningful statistics: shots against on target accuracy (32.55%), conversion rate (8.95%), shots on target conversion rate (27.28%), expected goals per shot (0.095), expected goals per shot on target (0.268) and big chances converted per game (0.58). No wonder most of our Italian imports to join our defence have done well in their transition to the Premier League pitches!

With the help of Excel’s Sort feature, this is the picture we get.

And this should fall within some expectations. Serie A reigns supreme and Premier League’s often chaotic ways of play have them dead last in the five-league group. Ligue 1, despite the might of PSG, still have some solid defences — even if they have some meaningful aid from their peers who are simply not that great in attacking. Meanwhile Bundesliga and La Liga are competitions for shot-stopping goalkeepers only.


And now, onto the shots zones statistics.

This is much simpler since we do not have the conversion numbers available for each zone. And given how there aren’t big differences between the leagues, there is no need to delve too much into it. Still we see how the PL are at the same time the worst side — tied with the Bundesliga — in keeping shots away from danger zones at 5.02 per game while being the best in within box shots against them — this time tied with Ligue 1 — at 1.94.

Maybe some would expect the English league to also have the biggest number of headed shots overall but this instead falls onto Germany at 2.15. As a matter of fact, the Premier League are below the 2.08 average with 2.02.

AND WHAT ABOUT CHELSEA?

For this section, we shall compare the Blues with the best six teams not only in the Premier League but also in the rest of Europe. First, the complete numbers with Chelsea on top for those who want to see it.

And here is the one with “per game” stats, ranked by conversion rate.

Chelsea may not have the best defence in Europe as the title is firmly at the hands of a bafflingly effective Atlético Madrid side, with Barcelona and Napoli behind them. Still, out of 30 teams ranked above we are 9th in conversion rate while performing comfortably above average in all but one category: the difference between goals suffered and expected goals from shots on target (0.016 against -0.060 on average).

Yet again, a pretty good picture for the Blues. And once Courtois returns to his usual world-class form, things should only get better for us.

CONCLUSION

Even with the limitations of not having access to advanced data, we can see what makes defences good or bad. It is not just about restricting shots but doing your best to contain them to areas from which they pose as little danger as possible to your side, and combine that with a quality goalkeeper as the last resort for when things go awry. Liverpool are the a good example of that as they are generally good in shot containment, but their goalkeeping is just very, very bad.

In these aspects, Chelsea could be set for the future with a backline of Andreas Christensen, Antonio Rüdiger and César Azpilicueta — or perhaps just the first two depending on whether or not we maintain the three-man defence — faring quite well. Having Courtois renewing his deal and getting back to his best, or bringing a capable keeper to fill in his shoes such as Roma’s Alisson in case he leaves the club, would put us in a very comfortable position for years to come in terms of personnel.

But a good defensive system relies mostly on the coach. And if we are to keep this defensive stronghold, it would be best to keep Antonio Conte at Chelsea’s managerial helm. Otherwise, we may have to take a good look at coaches such as Napoli’s Maurizio Sarri or Juventus’ Massimiliano Allegri who have shown that their teams are more than just a pleasing sight of flair on the Italian fields.