Three men in suits, one interviewer, Sky Sports One, ninety minutes, pure inspiration. Sometimes you just need a little spark to get your writing going again, and for me, this show worked. In case you missed it, you can listen to the podcast version of this interview with Sam Allardyce, Damian Comolli and Chris Anderson here. Three men with different backgrounds, yet one conviction: the use of data provides you an advantage in the playing field that is professional football.
Ironically, when I listen to something I am immensely grasped by, instead of concentrating on the presentation at hand, my mind goes off wandering. This also happened during the show. There were so many great talking points that I could hardly resist chewing on several concepts, at the risk of missing content.
Do these men on TV really focus on shots on target, ignoring the heterogeneity of that parameter? Are clean sheets really that important that focusing on defense over offense pays off? And who should be the Dutch equivalent of Allardyce, a manager often portrayed less sensible than he is, convinced of the use of data? Which two other guys would be able to fill in an talk sensible analytics on a Dutch TV broadcast?
The bucket game
But the main thought that crept in my head was of an old game we used to play on summer days when I was a little kid. You were handed a pretty large bucket of water, with the sole and simple goal of bringing this bucket over the finish line, with as much water as possible still left in it. This was complicated by the fact that the bucket contained some holes, small and larger ones, which allowed the water to leak out freely, if you didn’t control the holes with your fingers.
But controlling the waterholes required the use of at least one hand, which significantly slowed down the process of walking the bucket towards the finish line. Most kids started out at a frantic pace, allowing the water to leak freely, but rushing the bucket to the finish line, only to find out that this was not the optimal strategy. On the other hand, concentrating too much on keeping the holes as tight as you could did not win you the game either, as the bucket was created to prevent you from stopping all the leaks simultaneously. Therefore, a balancing act between stopping leakage and keeping the pace going was the best.
So, why am I telling this long introduction story? Because it makes up a perfect metaphor for a football match, and it that sense it kept creeping up my mind during the footy stats debate on Sky. Football teams are just like the water bucket. The water is their possession of the ball. Some teams focus too much on preventing the water from leaking out and fail to create enough output, while others rush to the finish line, losing a lot of water along the way.
This theoretical metaphorical talk will probably work better with a real life example at hand. Let’s focus on what’s presently my favorite study object, PSV, and try to implement some of the detailed performance statistics that we can gather from various sources around.
PSV are an interesting case study, because, as you’ve probably noticed, things are not entirely going according to plan. Instead of competing to the title, they have hit a two-wins-from-twelve streak and are currently back in 10th position. Pressure on young manager Phillip Cocu is building and it remains to be seen if Cocu is allowed to even finish his debut season.
As I wrote for De Volkskrant, PSV have a huge offensive problem, and that is part of the reason I’ve picked them for this case study. After all, defensive stuff is still next to impossible to analyze with public data focusing on on-the-ball events. PSV create the 3rd most shots of the Eredivisie, yet their horrific shot quality makes them only rank 11th in terms of Expected Goals scored.
Let’s assume PSV starts with a full bucket of water – there’s more in this metaphor as the point of regaining possession may represent the amount of water to start with – and conclude that they don’t carry enough of it over the finish line, or in other words, they don’t create enough shots of decent quality.
Now, where do PSV leak?
At around 380 completed passes per match, PSV are well behind Ajax (530), Twente (450) and Vitesse (410). In the reverse stat, passes completed by the opposing team, PSV (270) is at a level playing field with Vitesse (260) and Ajax (270) and slightly ahead of Twente (300). So, PSV is less of a passing side, but out of possession it keeps the pressure on, like the other top teams. I’ve deliberately left Feyenoord out for now, not because I don’t rate them at the same level as said teams, but because their profile is quite different, which makes them a nice case study for later.
Another interesting way to look at passes is the amount of incomplete passes. Variation here is self limiting as you can’t keep losing huge amounts of passes, since in between each lost pass, you’ll need to win the ball back first. So, less spread among the teams, and PSV comes in nicely at 86 incomplete passes per match, ahead of Ajax (88), Twente (90) and Vitesse (94).
Where is the leak?
Now, where do teams leak the water? Which players are responsible for the mainstay of misplaced passes? Naturally, going from front to back, outfield players should have a decreasing amount of misplaced passes, as defenders have less opponent pressure to worry about when passing and the consequences of their misplaced passes can be more severe.
PSV’s top players in terms if misplaced passes are Stijn Schaars (11.3 per match), Jetro Willems (9.7) and Adam Maher (9.2). Yes, you read that correctly, two of PSV’s midfielders are responsible for 20 misplaced passes per match.
The context for this number consists of Ajax (Poulsen 4.9, Blind 7.0), Twente (Gutierrez 8.3, Eghan 6.4, Ebecilio 5.2) and Vitesse (Atsu 6.1, Vejinovic 4.8). PSV ‘s rivals lose around 11 to 12 passes in central and defensive midfield, PSV around 20.
So, the problem is not the amount of passes going astray, but probably the area where they do.
This would be okay-ish if the likes of Maher, Toivonen and Schaars had enough offensive output going to make up for it, but that is definitely not the case. PSV’s strikers get a horribly low amount of touches on the ball, which may be partly their own fault, but if I were to manage a football team, the midfielder should know it’s their job the make sure the striker sees enough of the ball.
Matavz (12.4 passes per match) and Locadia (13.8) are bystanders in comparison with Sigthorsson (26), Havenaar (25) and Castaignos (23). If all your rival teams note performances that are this close in the same range, you’re probably the outliers, and not in a positive sense.
In the end
Overall, it seems PSV are leaking to much water to get a top level offense going. The paper I wrote for De Volkskrant already diagnosed the horrific shot quality, with main contributors Depay, Bakkali and Maher. Today’s article on 11tegen11 goes into more detail and highlights their water leak in midfield, with Schaars and Maher misplacing nearly twice as many passes as rival midfielders do. As long as Cocu does not fix these type of issues, the leak will continue and results will continue to surprise in a negative sense. Performance data are here to help, and this type of analysis is an example of what quite superficial passing information can already tell you.