A lot of the growing field of football analytics seems to be looking for that moneyball-esque holy grail: a way to beat to the system and to predict team and player performance before the results are visible on the league table. I want to set my sights a little lower and ask the question if we can even distinguish different tactics by looking at the numbers.
I’d like to focus as little on team quality as possible (although I may have to), and the 2013/2014 Eredivisie seems to be a good place to look. With the first ten teams within six points after 13 rounds, it seems perfect in that the end result of a lot of the teams is just about the same, but there may be wildly different ways of getting there.
Although this article is about tactics, it’s not about formations. They are hard to tell apart without taking a much closer look, and in my personal opinion they are not as relevant as they are made out to be. I think a much more obvious expression of a team’s tactics is their style/approach. Keeping possession vs directness, pressing high vs dropping back, etc.
For example, here’s a common observation about Frank de Boer’s Ajax:
- They press high on the pitch
- When they get the ball they safely pass it around the back (artificially inflating their pass and pass completion stats)
- They don’t create enough chances.
I mostly agree with this assessment personally, but I wanted to see if I could get some statistics on how much they differ from other Eredivisie teams in this regard.
I took data from Opta through Squawka.com (fully available since the second round of the league), which includes information about tackles and interceptions per match, and where on the pitch they took place. It appeared to me that a good measure of “high pressing” would be the percentage of pressing actions (tackles + interceptions) on the opponent’s half, so that’s what I counted to start with.
Note that the absolute number of pressing actions on the opponent’s half doesn’t tell us much because weaker teams make more defensive actions altogether (after all you can only do it when the other team has the ball).
The metric for “indirectness” I propose is quite simple and readily available: passes per attempt. How often does a team pass the ball around before they take a shot?
Using both metrics as an axis results in the following graph:
First of all you can see that Ajax is indeed an outlier with both the highest measure of “high pressing” and the highest score for “indirectness”. However, some other teams stand out as well:
- Heracles – Look on paper to be a classic counter-attacking side. Like to sit back and are quick to strike when they get the ball. The opposite of Ajax.
- Cambuur – About the same pressing as Heracles, but almost as indirect as Ajax.
- Twente – Seem to be in the best position by putting the opponent under pressure and capitalizing on it quite quickly.
In general it seems that the better teams tend to the right side of the graph. High pressing may not be a measure of quality, but it’s a luxury in the sense that only good teams can afford to do it consistently.
RKC and NEC especially seem to have little choice in the matter. They are perfect examples of teams that in most matches are simply “pinned back”, “park the bus”, or deem any other option to be suicidal.
AZ, Groningen and Zwolle employ surprisingly little high pressing despite their position in the league, but interestingly AZ has actually moved from 19% high pressing and 33 passes per attempt under Gertjan Verbeek, to 24% and 38 p/a under Dick Advocaat.
To visualize the relationship between “quality” and high pressing I’ve used Total Shots Rate: attempts / (attempts + attempts conceded). See 11tegen11.net for more about TSR.
There’s a clear correlation between the two (0.83), but a few teams stand out a little. Zwolle, Heracles, Vitesse and Twente all have relatively good TSRs for the amount of high pressing they do.
Looking further into passes / attempt shows that Ajax and Cambuur are not as similar as they look at all. Cambuur’s average amount of shots per match is simply very low, while Ajax may create less chances than they should, but their “indirectness” is probably mostly a choice as shown by their sheer number of passes.
Now, it’s clear that keeping possession is often not an offensive, but a defensive tactic. My last graph attempts to show this by comparing passes with conceded attempts (shots by the opponent).
There’s some very interesting clustering going on here, and Ajax do indeed manage to get away from the pack in terms of conceded attempts by keeping possession, but Twente do much better still. In fact Twente look “good” in every statistic so far and have far and away the best TSR. Despite Ronald Koeman’s insistence that one of the classical top three will grab the title, they may be the team to look out for.
ADO Den Haag are interesting as they have a TSR of over 0.5 while having the lowest possession in the league, and Heracles are not much different. Remarkably both teams seem to have bad luck in terms of conversion so far and their current league position is lower than their TSR would indicate. Is this somehow a result of a counter-attacking style? To be honest I don’t think I’ve watched an entire match of either team this season but it’s certainly food for thought.
Author: Bart Schotten