2009-10 Offensive Production in the Big 4: Comparing Teams' and Leagues' Accuracy and Conversion Ratios

Now that the big leagues of football are finally underway, I thought it'd be fun to take a quick comparative look at last year's goal and shot ratios across teams and leagues. Recall, for starters, that the total yield (goals per shots taken) is typically very similar across the four leagues. It is usually right around around .111, as good old Charles Reep would have predicted. So in the 2009-10 season, for example, the average yields of goals per shot were as follows:

Bundesliga: .113

Premier League: .117

Serie A: .106

La Liga: .108

This spells 1 goal in roughly 9 shots taken. Clearly, the major leagues are very comparable on this dimension, with 2009-10 producing yield rankings that put the EPL and the Bundesliga ahead of La Liga and Serie A (in that order).

But these averages for the leagues as a whole hide a lot of very interesting variation. Across the leagues, yields vary from slightly greater than .05 (that's 1 (one!) pitiful goal in 20 shots) to Barcelona's astonishing yield of .168 (roughly 1 goal in 6 shots!). But interestingly, the variation is on a similar scale, with the less efficient teams across the leagues (Hertha BSC, Nuernberg, Portsmouth, Wigan, Lazio, Livorno, Espanol, and Valladoli, to mention a few) managing a goal ratio of only slightly greater than .05, and the successful teams (Bayern, Schalke, Man City, Chelsea, Sevilla, or Inter) producing yields around or better than .15.

As always, aside from yields, an interesting question is how well teams do at managing to hit the goal (accuracy, measured by the SOT/shots ratio) and actually scoring when hitting the goal (conversion, measured by the goals/SOT ratio). So let's take a look.

China and Liverpool: Why Would China Buy an EPL Team And Why Would Anyone Care?

Marina Hyde's scathing, acerbic, hilarious, and accurate piece "We're living in the age of the football-industrial complex" makes a compelling argument about hypocrisy and ownership in the EPL. It's about the proposed takeover of Liverpool by a Hong Kong based (and possibly China backed) investor. And while the most recent takeover proposal may or may not be dead for now, the piece made me wonder whether I really should care about the nationality of corporations or individuals who own and run EPL teams. And whenever I'm not sure about things - which happens quite frequently, I hate to admit - I make a list of pros and cons or "on one hand" and "on the other hand". So here we go.

Here's why we should not care who owns Premiership teams:

• Professional football is a business.  So the laws of the market apply and individuals and corporate entities will invest in clubs if they see them as profitable and matching their organizational strategies. It's their business, not ours.
• Professional football is a relatively small industry that is dwarfed by many others (in terms of its size as a proportion of the economy as a whole). So, what's the big deal if a few Chinese or Russian or Middle Eastern businesses own EPL teams? 
• Buying a football club is part and parcel of foreign direct investment in the UK economy. Clearly, there has been an increase of FDI in the UK (as there has been in China - see chart below). So if UK businesses can invest in China, Chinese businesses should be able to invest in the Uk, right?!

• It's not at all clear that the Chinese government's investment arm is actually involved with the current proposed takeover of Liverpool. But aside from the facts of any kind of involvement of the Chinese government's sovereign wealth fund (or any other entity), which suggest that the Chinese government is not involved, why shouldn't sovereign wealth funds invest in opportunities like EPL teams?
• People in the UK do not have an unfavorable opinion of China - in fact, the Germans and Japanese have far more negative attitudes about China (the PRC that is, not Hong Kong), as the results from a recent Pew Poll show. So if the British in general don't dislike the Chinese, why should football fans dislike Chinese investors bearing loads of cash?

So, given all these reasons why we shouldn't care, you may wonder why we should. Good question. So here's the list of why you should be for and against the takeover of EPL teams by foreign investors.

Eliminating Draws: Sepp Blatter's Latest (And Not So Greatest) Idea

In a recent interview with the German news magazine Focus, Sepp Blatter resurrected his by now well rehearsed idea to scrap draws at the World Cup and replace them with an immediate shoot out. Given that I spent a little time looking at draws during this past year's World Cup, I wondered what the esteemed Mr. Blatter was basing this proposal on. Call me a purist, but it's not clear to me that eliminating draws will produce better play or more exciting play. Anyone who watched New Zealand play their hearts out at this year's World Cup (becoming the only undefeated team in the tournament along the way) will know what I mean. And anyone who's ever played the game and managed to turn certain defeat into a draw knows the joy that draws can bring (and anyone who's managed to see a certain lead turn into a draw the agony of a draw).

The one thing we know is that matches that end in draws see fewer goals. I did a quick and dirty analysis of goals scored in the Big 4 league matches over the past five years, and the proportions are roughly 3 goals in matches that end in wins for one side and 2 in matches that end in draws.

But perhaps Sepp Blatter knows of another pattern in World Cup outcomes that had escaped me: perhaps the number of draws had increased so that FIFA officials are worried that spectators might lose interest in the matches (the latter being a remote possibility, given the amount of money FIFA has been able to make off the men's World Cup).

So, I cranked up the old World Cup dataset to see how common draws are at the World Cup and whether they have become more common. Here's the total number of draws at World Cups since 1930. And, aha, there it was: the number of draws has increased over time from 0 in 1930 to over 30 in 2010 (actually, to be precise, the number is exactly half that because I have counted draws by team, and every team that draws by definition draws another team). But perhaps, this is what President Blatter noticed.

Well, I hope that's not what it is. The problem with this count is, of course, that it disregards the tournament format, especially the number of teams, and changes in first and second round play (and the possibility of draws) that have occurred over the years.

Game On: Goal and Shot Ratios in the EPL

Recall from my earlier post that the 2009-10 Premiership season was unusually rich in goals. The season came within a whisker of having the most goals ever in the history of the league, and its 1,053 goals and 2.8 goals per match were among the highest ever.

So now that the first matches have been played in this year's EPL season (with the exception of Monday's Man U - Newcastle matchup), I thought it'd be useful to take a quick look at goal and shot ratios for 2009-10 to get us up to speed on how teams got there, and what this may hold for 2010-11.

Before looking at the data, recall that the ratios of SOT/Shots > goals/SOT > goals/shots. This means that shots are more likely to be on target than to yield goals, and that goals are more likely to be scored off accurate shots than just shots (none of this should be a surprise to anyone, but it helps to know this pattern when looking at the data).

So which teams were most and least trigger happy in the EPL last year? The chart below shows the average number of shots a team took per match, and it looks very similar to what the league table looked like most of the season. But if you look closely, there also are a few interesting exceptions.

On average, EPL teams took slightly more than 12 shots per match (12.22), and the range was as low as 8.34 for Hull and as high as Chelsea's 18.34. And it's no surprise to see that Chelsea, Man U, Tottenham, Arsenal, and Liverpool led the league in creating opportunities to take shots on goal. The team that's missing from this list of top clubs is Man City, which is very much in the middle of the pack when it comes to taking shots on goal.

But if all it took to stave off relegation was taking shots on goal, then Portsmouth would have easily been saved and Wigan wouldn't have been anywhere near the relegation battle, while Birmingham would have been in some trouble (which they weren't, of course).

These numbers are interesting, as far as they go. But as I've mentioned before, converting shots to goals is about more than randomly slinging the ball in the general direction of the opposite goalkeeper. Specifically, aside from taking shots, it requires shooting somewhat accurately to give the opposing keeper something to do and converting accurate shots into actual goals.

So here are the 2009-10 EPL ratios on goals, shots, and shots on target:

On average, there is a fairly narrow distribution in goal/shot ratios across teams (these measure how often teams score, given the number of shots they take). In 2009-10, the EPL followed Charles Reep's 9 shot maxim (that, on average, one goal is scored for every nine shots) almost to the decimal. Reep's prediction would yield a goal to shot ratio of .111, whereas the 2009-10 EPL season yielded a .116 ratio.

But averages don't win titles. You can see from the graph that the successful teams had a much higher yield around .15 (about one goal in seven shots), whereas the least efficient teams came in much lower. Portsmouth and Wigan's roughly .07 (yes, that's 1 goal in 14 shots) pale in comparison to Man City and Chelsea's .16 (that's 1 goal in 6.25 attempts).

So the question is this: is this difference in yields due to accuracy - do the Chelsea's of this world shoot more accurately? - or is it because of differences in conversion - do accurate shots taken by these team find the back of the net? As it turns out, it's clearly the latter.

Show Me The Money: The Richest Clubs in the World

Don't know if you've seen this, but here's a nifty graph of the richest clubs, defined in terms of revenue (not bottom line, mind you). It's pretty! But it also contains some useful information. While there are no real surprises - most of this information is available elsewhere - there are a couple of noteworthy things:

Revenues
It's interesting to see that Chelsea is among the losers in the revenue game, essentially holding steady over the previous year while other teams have prospered. And Liverpool and Juventus both moved up, despite less than stellar seasons. Other interesting facts of note:

Goal and Shot Ratios: The Big 4 Leagues

Following up on shots and goal analyses from the last few days, here are goal and shot ratios for 2009-10 for the Big 4 (Bundesliga, EPL, La Liga, Serie A). One thing to note up front is that, in each of the four leagues, shots on target (SOT) and shots on goal (SOG) are (unsurprisingly) positively correlated with goals and wins. This means that the more you shoot and the more accurately you shoot, the more you score and the more you win. Importantly, shots on target (SOT) are more highly correlated with outcomes than shots on goal (SOG).

With that out of the way, here's what we see:

Bundesliga Postmortem 2009-10 and Statistical Preview: Trigger Happiness and Finding the Target

If all it took to win the Bundesliga was taking shots on goal, then last year's champions would have been Bayer Leverkusen (with 15.7 shots per match), and the season would have been a close race between Leverkusen and Werder Bremen (15.5). And even if it wouldn't have won them the league, Hertha's and Nuernberg's 12.8 and 12.4 shots would have put them safely in the middle of the pack, rather than force them into a relegation battle that Hertha didn't survive.

Take a look at which teams were most and least trigger happy in the Bundesliga last year.

On average, Bundesliga teams took almost 13 shots per match (12.97), and the range was as low as 9.47 for Cologne and as high as Leverkusen's 15.73. Alas, as we know, Leverkusen didn't win the league - Bayern and its average 14.53 shots did - while Hertha is about to start on its campaign to make it back to the Bundesliga from the purgatory known as 2. Bundesliga. Clearly, just taking shots doesn't win the league, and not shooting as Cologne and Mainz did doesn't force you into the relegation zone. To win, you have to convert shots to goals. So how did clubs fare and what may it tell us about this year's season?

Comparing the Big Leagues of Football: Goals and Shots, Home and Away

As a follow up to the earlier posts about goal trends in the English Premier League and league success at the World Cup, I thought it might be fun to see how the "Big 4" soccer leagues (EPL, Bundesliga, La Liga, and Serie A) compare. I have to admit that I didn't have any strong priors about what the data might tell us. On one hand, you might expect that leagues' results reflect different styles of play and tactics. So, off the bat, you might see fewer shots on goal in Italy and Germany than in the EPL or La Liga. On the other hand, you might argue that these leagues have become so thoroughly internationalized (see my earlier posts of teams' league origins in the World Cup), with player and manager movement and the diffusion of soccer knowledge across the globe, that you wouldn't expect too many differences across the top leagues.

To make things comparable and recent, here are data for goals and shots by match since 2005 (the last five seasons). First, let's look at total shots on goal per match - overall and by home and away teams.

Here's what stands out, if you ask me:

Which League Won the World Cup?

Here's the most recent ranking of the European leagues, according to UEFA.

The ranking suggests the following hierarchy of leagues (based on calculations over five seasons): the Premier League, La Liga, and the Bundesliga are currently the top 3 leagues, followed by Serie A, Ligue 1, and the Ukrainian Premier League. But if you look at the UEFA coefficients a little more closely, the numbers suggest that the hierarchy is slightly more subtle, with the EPL and La Liga on top, followed by the Bundesliga and Serie A, with Ligue 1 bringing up the rear of the top 5 leagues (and the others significantly behind). (and of course, there are annual variations - for example, Serie A's coefficient for this last year is slightly higher than the Bundesliga's, if only slightly).

If you ask me, this sounds about right. But here's another, and visually fun way, to gauge the quality of leagues. Let's take a look at which leagues did particularly well in the World Cup, as measured by players from some leagues making it further into the tournament than others.

Take a look. You can click on the graphic and generate different versions of league success by different stages of the tournament (group stage, round of 16, quarterfinals, and semifinals).

Goooal!! Trends in Scoring in the English Premier League 1993/4 – 2009/10

With the start of the Premier League season little more than a week away, I thought I’d take a quick look at what we can expect to see this year. And what better place to start than with goals?! Here are the trends in total number of goals for the league since the 1993-94 season.

Are Asian Teams More Disciplined?

If you haven't seen this, I thought this was really worth a read. It's a piece about cultural stereotypes and styles of play we saw in the World Cup (and see in international competitions). I found it on Christian Collet's excellent blog a few weeks ago. It raises several really interesting questions about what it means for a team to be "disciplined" or play "as a team" or "work hard" and also how we might measure these things.

How Argentinian is Lionel Messi, and How Danish Is Nicklas Bendtner? A Different Take on Player Backgrounds at the World Cup

How Argentinian is Lionel Messi? Sure, he was born in Argentina, but left for Barelona when he was 13. So is he more "Argentinian" (as a soccer player, of course" or more Spanish (or Catalan, if you like)? Messi isn't the only one about whom you could raise this question. Nicklas Bendtner went to Arsenal when he was 16. The reverse is true as well: some players leave their home country and play for their adopted country - think Alfredo di Stefano - and in recent years, changes in citizenship laws have made it easier for players to maintain dual citizenship and choose the side they wish to play for - think Mauro Camoranesi or the Boateng brothers.

In an earlier post, I (implicitly at least) raised the question of how "German" the German team really is. But instead of categories like citizenship or ethnicity, why not think about the composition of World Cup teams in terms of where players ply their trade?

Thanks to Carlos Lemos and Daniel Lima from Estadao, here's a great analysis of where World Cup players play their "regular" soccer - that is, the league and country they compete in for their day job. Click on it, and you'll see output that connects each country/team with the league their club team plays in.

The Home Continent Effect That Wasn't

Remember how home country or continent is a good predictor of World Cup success? Still wondering why playing on their home continent didn't propel one of the African teams into the semifinals or finals of this year's World Cup?


Take a look at these beautiful and haunting images, and you'll get a sense of why Africans love soccer, but why they may not have the resources to travel across the continent to support their national team (see also the related story).

Credit: Jessica Hilltout/The AMEN series