Goals Against, Big Four plus EPL and Bundesliga (2009-10)

While offensive production has been one important story of the Premier League season so far - in particular for leaders Chelsea and Arsenal - matches aren't won with offense alone. At the end of the day, it is the difference in goals that matters, and for that, defensive production is important.  Here's how the Big Four leagues stack up, using data from the 2009-10 season (no good reason to assume this year will be any different).

Of course, this is basically the offensive home field advantage in reverse (home teams are able to force away teams to concede more goals, and away teams are less able to get home teams to concede goals). So league totals are not entirely useful. But bear with me since I think it's instructive to think about the same data by looking at them in a slightly different way.

So back to defensive production. Overall, the big leagues look quite similar. There is a home team defensive advantage in each of the leagues, with home teams giving away fewer goals than away teams. This defensive advantage is least pronounced in the Bundesliga and most pronounced in the Premier League. Moreover, home teams defend least effectively in the Bundesliga, and away teams' defenses are most porous in the Premier League.

These overall figures hide considerable variation, as you can see when you drill down further into the leagues. So let's look at the Bundesliga and EPL to get a sense of this variation by teams (again, for 2009-10).

While the defensive home team advantage holds for most teams in the Bundesliga, it is astonishing that some teams - and even some very good teams like Wolfsburg - defend less successfully at home than on the road. Aside from Wolfsburg, teams in this category include Cologne, Bochum, and Stuttgart (though there's hardly any difference for the VfB). This could be because they play a more open game at home to give their supporters something fun to watch, but I have my doubts. As importantly, the top teams are just outright stingy on defense. Teams like Bayern, Schalke, Stuttgart, Leverkusen, and Bremen have records of around 1 goal against per match at home and away. Top teams defend well, no matter what.

Let's see if that's the case in the Premier League, too. Clearly, it is. Virtually all of the top teams have great home and away defensive production.

Take a look at Many U and Chelsea, for example, who are even stingier than Bayern were in their highly successful season. But Liverpool, too, did well. The difference between the very top teams and the also-rans last years (like Aston Villa, Arsenal, and Tottenham, for example) seems to have been defensive production on the road. These teams were not able to replicate their stellar defensive production at home when facing teams in less friendly confines. At the bottom, teams like Wigan, Burnley, and Hull leaked like sieves, though more so on the road than at home (and Wigan's woeful 11 against goal record at home so far this year does not bode well for Roberto Martinez's club).

These data raise some interesting questions about home field advantage, but also about how much defensive production matters to offensive production, or whether losing by 5 is any worse than losing by 1. I'll take a look at the connection between goals and wins, and shots, goals, and wins in one my next posts. Stay tuned!