A short sermon from me today: it’s Friday, and there isn’t much going on this weekend save for the odd friendly, and the MLS games which you should all watch.
This post is going to piggyback on some of the fine work of others, so I’ll thank them in advance for their great work.
Ted Knutson wrote this post titled “Positioning is Everything” in early June, and the more distance in front of it, the more I think this might be among the most important articles of the summer (at least in my mind; who am I to judge?).
While I’ve already written about his post, it’s worth a quick revisit. Basically Knutson’s point is that while shot studies are useful in soccer, they don’t tell the whole picture. Knutson argues analysts could do much better to judge shots based on the position of the opposition players:
Take any moment in time where the ball is in the attacking third, look at the current ball position and the positions of the defenders. Then analyse the probability of a goal being scored by a shot in that location. Do that with enough shot and position data, and you construct a model that tells you how likely any shot is at creating a goal based not only on shot location, but also on defender location.
25 shots per game… 380 games per league per year… it would take about two years to reach 100K shots from the big five leagues and have an enormous database of shot success vs defender positions to analyse.
Why is this important? Well, because a lot of people want to know why teams like Manchester United and Barcelona ran away with their league titles last season without crushing opponents in their shot ratio. Put plainly, these teams took fewer but more accurate shots, over and above the mean shot conversion rate. In short, they shoot more accurately, consistently. This is in part reflected by United’s high PDO (shot % plus save %).
Meanwhile Manchester City’s PDO was very slightly below the mean, even though their shots ratio was the highest in the league. So what’s the deal?
…I am struggling with how City posted a sub par PDO (http://t.co/4UZXl10JS8) if CCC and Inbox (location proxy's) were so good
— Ben Pugsley (@benjaminpugsley) July 26, 2013
Ben Pugsley tweeted this, and then after speculated on his own theories. One of them is the fact United spent quite a lot of time in comparison to City (and the league) with a +1 lead, which readers of this site will know means they took fewer but more accurate shots. But another Tweeter had this theory:
@benjaminpugsley because mcfc were slower than treacle while united transition quickly. U matched them for quick breaks in title season
— Differentgame (@footballfactman) July 26, 2013
Slow? Meaning, slow to get ahead of the opposition defense? Definitely passes the smell test if you watched more than three City games last season.
Had we had Knutson’s as yet non-existent positioning information, we could draw a better conclusion about the circumstances in positioning that allows teams to take better quality shots. You could also apply this stat to Barcelona. Mike Goodman wrote on Barca under Pep for Grantland today, and touches on similar themes:
Bayern won last season because they outshot the opposition, pure and simple. They shot the ball, won it back, and shot again, over and over and over. Guardiola preaches keeping the ball until you can’t help but score, but he’s inheriting a team that excels at pounding away, battering ram style.
When you stop to break down the numbers it’s truly astounding how little Barcelona actually shot. They averaged 13.9 shots per game last season, only sixth most in La Liga, and less than one shot more than the league average. That would be unremarkable if they didn’t keep the ball for a truly mind-blowing 69 percent of the game.
Combine a barely above average number of shots with bananas-high possession and you get a team that plays really, really slowly. When some soccer snobs claim to be “just so over” tiki-taka, and describe it with words like metronome, machine-like, and joyless, this glacially patient pace is generally what they’re responding to.
So now we can begin to connect the tactical dots just based on what we know about how these teams actually play football. Bayern is quick, hogs the ball, scores from crosses, and generally peppers the opposition into submission. Barcelona maintain careful possession but are patient and wait for their moment (perhaps when the opposition defense hasn’t yet organized) to score. Man United take early leads and transition very quickly in attack, taking fewer but more deadly shots.
This is just utter bald-faced speculation from yours truly. Had we had Knutson’s magical positioning data, we might have a much better answer to these questions. ARE YOU LISTENING STATS WEBSITES?