Defensive Performance in the Top 4 European Football Leagues: A Statistical Review of the 2010/11 Season


Despite what Cesar Luis Menotti may want you to believe, football is a game of offense and defense. So as a follow up to my recent post on last season's offensive performance in the big leagues, I thought it was only fair to defenders and goalkeepers to take a look at who has been doing a great job keeping the opposition at bay. As before, I calculated averages on shots, accurate shots, and goals per match - but of course, this time around we're talking about shots and goals conceded.

So which teams dominated Europe in terms of preventing opponents from taking shots last year and which seemed to issue open invitations as soon as the referee blew the whistle? First up, the average number of shots conceded per match.

Turns out, many of the top offensive teams also came out as top defensive teams last year. Perhaps heeding Cruyff's advice that the other side can't score if they don't have the ball (I'm paraphrasing), Barca allowed the fewest number of shots on goal in all of Europe. That's an astonishing testimony to their ability to keep the ball away from the other side, and explains why they could dominate La Liga and Europe despite having defensive players that are not on par with their midfield and strikers, quality-wise. We already knew that Arsenal actually defended very well in the Premier League last year, but it is perhaps a little surprising this put them second in Europe in terms of allowing the other side to take shots. Surprises at the high end of performance: Nuernberg and Newcastle.



But shots don't have to be accurate to count. So which teams did particularly we degrading the quality of shots taken - measured as the average number of accurate shots teams conceded in 2010/11?


This is where the rubber meets the road and non-English teams show the best performance, with Dortmund, Barca, Real, Napoli, Milan, and Leverkusen leading Europe last year at around 4 shots or fewer. The highest ranked Premier League team on this dimension was Arsenal again, but well in the middle of the pack. And at the low end, we see a who raft of Premiership teams - of course, this in part speaks to the accuracy of Premier League shooters, but also to the leakiness of some of the league's lesser teams.



As before, shots don't mean goals, so who gave up the prize that really matters in football? Take a look at the average number of goals conceded per match in the next graph.

One thing to notice is the considerable range across clubs - with some giving up slightly more than half a goal on average (Barca, Milan, and Dortmund), while others like Gladbach, St.Pauli, and Blackpool made their keepers pick the ball out of the next twice per match on average. Another pattern of note: the good performance of Italian sides, a good number of whom are located in the upper half of the distribution.



To get a sense of which teams let in more goals than average numbers of shots would predict and which teams were able to keep more goals out than what we would predict, I graphed teams' average shots and goals in a scatterplot, imposing a linear regression line. Teams above the line conceded more goals than they "should", given teams' average performance; teams below the line conceded fewer goals than we would predict based on the number of shots.

On the underperforming side (teams above the line), we can see many of the usual suspects, with relegated teams like Blackpool and St.Paul conceding lots of shots and goals and more goals than we would expect. In fact, Blackpool have the dubious distinction of "leading" Europe on this score.

The graph also is informative because it points to some weaknesses that some of the better teams had last year. For one, it suggests in part why a decent team like Werder Bremen had such a lousy season last year. But Arsenal and Leverkusen, too, conceded slightly more goals than they should have (statistically speaking). In stark contrast, the league winners Germany, Spain, and Italy all did incredibly well when it came to defending, and Barcelona did best. Several of the top Premier League teams, including Manchester United, Manchester City, and Chelsea too, did well and better than we would expect based on the average team. As before, a good number of Serie A teams were below the line, indicating that the league saw fewer goals than the others last year more generally.




So as you enjoy the first few weeks of the new season, enjoy the goals your club produces, but don't forget to applaud those defenders blocking shots or goalies making heart-stopping saves. They're as important for your team's fortunes as those glamorous and glorious strikers.

dorutmond, wow, they are something. its a shame they loss sahin. that team would be some challange to beat.

this is just spanish, english, german, and italian?

i just briefly glanced the teams.

interesting perspective though, kudos.

nice post man... have to read your 'offensive one' too