Category Archives: World Football


Toward a model of adjusting player stats for the “personality” of the team and the league

As I said in my first article on this topic I think that Ted Knutson from StatsBomb has a good idea. Individual player’s stats are deceptive and need to be grounded in the context of the “personality” of the team he plays for and the League he plays in. The idea of adjusting individual’s stats for the personality of the team, in his formula he used possession, is solid. The problem is that possession doesn’t map to defensive stats because possession is simply a ratio of passes.

The reality of football is that teams vary wildly in terms of their defensive aggression. How often a team attempts tackles or gathers interceptions has a very weak correlation to possession stats. I want to be clear that I’m not trying to hammer anyone here. Rather, I’m trying to build on Ted’s idea and create a new model which will help us to understand individual player’s stats better.

To that end, take a look at the chart of Premier League teams below (click to embiggen):


In this chart I have sorted the 20 League teams by possession. I have broken down each team’s tackles and interceptions. Then I have taken the League averages for the tackles and interceptions (added together) and the averages for tackles and interceptions. Then I have done a +/- over the average for total, tackles, and interceptions.

What you can see very clearly is that the top five teams who dominate possession also are among the most aggressive defensive teams in the Premier League, with the exception of Arsenal who are essentially an average defensive team. Those top five teams are making more passes than average (that’s what possession measures) and more tackles+interceptions than average. The next three teams are known as defensive teams and yet they have fewer tackles+interceptions numbers than average.

I think that the Chelsea numbers are a good clue as to why teams who have a reputation for boring and defensive football also are less active defensively. If you look at the whole chart, teams with a negative overall defensive number are all well known to be disciplined defensive sides. They aren’t diving into tackles or playing the passing lanes. They sit back, in two banks of four, and play positional defense. That’s my theory anyway.

So, perhaps we could adjust player’s stats based on an overall “defensive aggression” number? Even if we did that, however, we might be wrong adjusting certain player’s stats, like say tackles, on a team like Swansea who (as you can see from the chart) aren’t a very tackle oriented team.

Looking at the next two columns we see a further breakdown of each team’s defensive personality. For example, the most aggressive tackling teams are Stoke, Liverpool, Crystal Palace, Southampton, and Manchester City. I think that’s a fair assessment of the Premier League, actually. Stoke and Liverpool play smash-mouth football, which may offend some Liverpool fans but for anyone who has seen them play you know that they are scrappy and a bit dirty on the defensive end. Crystal Palace is another interesting team. I bet they avoided relegation last year simply with their amazing defensive work rate, that +299 with + in both tackles and interceptions is really crazy.

Regardless of whether you agree about my analysis of Liverpool and Crystal Palace, I think I’ve made my point here with regards to using possession as a means of adjusting player’s stats. Instead we should probably be looking at the personality of the team and using that to adjust a player’s stats. How, exactly, we adjust for that I haven’t figured out yet. I don’t have a math genius here to bounce ideas off of, like Ted does. If you’re a math wiz and you want to help, just leave me a comment below. I’ll get back to you.

In the mean-time, one more thing to consider: a team’s stats also vary from league to league. For example, the Bundesliga is a far more aggressive league in terms of tackles than the Premier League.

BundesligaRemember that Bundesliga teams only play 34 games a season and yet they are averaging 339 more tackles per season than their Premier League rivals! That’s 10 more tackles a game. Per team. For my money that seems like a much more important thing to adjust for than possession.

How do we do that? I don’t know, yet!





Why we shouldn’t adjust defensive stats for possession

“Have you thought about adjusting your stats for possession?” – Everyone since June

Last month the venerable Ted Knutson published an article strongly suggesting that us stats folks should adjust basic defensive stats like tackles and interceptions for possession. The theory being that the more possession (offense) a team owns the fewer opportunities that same team has to make defensive actions. If true, then we should adjust player’s individual stats for their team’s possession. It’s a good theory with only two minor flaws: 1) it’s wrong and 2) it’s wrong. I know technically that is just one flaw but it seems like such a big flaw that I felt it deserved to be repeated.

First, you have to understand what possession is and how it is measured. Opta measures possession simply as a ratio of passes between teams. Ergo if Arsenal make 600 passes and West Ham make 400 passes the possession numbers at the end of the game are reported as 60-40. Measuring possession as pass ratio has caused a good bit of consternation among stats nerds for a few years now. As you know, many teams, like West Ham, intentionally waste time when they have the ball in order to prevent teams like Arsenal playing. At the end of a match like that, however, a team with faster passing might end up dominating possession as something like 70-30 when in actuality the possession numbers were more like 50-40-30 with 30% of the ball being out of play.

Don’t believe me that a ball could be out of play for 30% of the match? Well, if we use the alternate method of tracking possession, the “chess method” where a clock is actually deployed and time measured for when a team has control of the ball we see that Bayern, for example, led the Champions League in possession last season at 65% and yet only had, on average, 38 minutes of play. 65% of 90 is 58.5. Where did the other 20 minutes go? Time wasting and other tactics to slow the game down.

But even if we were to accept the idea that possession is a “good enough” measure of offensive dominance and thus defensive opportunity it still doesn’t explain why a team like Barcelona who routinely have 68%+ of possession would wrack up fewer tackles than a team like West Ham who routinely have ~40% of possession. If the idea that less possession = more opportunity and therefore inflated individual and team defensive stats we should see West Ham, Fulham, and Crystal Palace blowing away teams like Barcelona in terms of total tackles and interceptions.

Or even if we were to stay in the Premier League and take Southampton, who led the Premier League in possession, and compare them to the bottom teams we should see the bottom teams have more tackles and interceptions. After all, they have more opportunity.

But rather than seeing a direct correlation between possession and defensive stats, we actually get a very poor correlation as you can see below. Southampton and Man City led the League in possession while West Ham, Crystal Palace, and Fulham were the bottom three in possession.



How is it possible that Southampton made 1802 attempted tackles and interceptions while West Ham, a team known as a tough tackling side who Stuart Robson loves to commend for “earning the right to play”, makes just 1456 of the same actions? That’s 346 fewer actions, almost ten a game! And Southampton has 58% of the possession compared to 42% of the possession for West Ham? The answer is simple: possession, or lack thereof, has little to nothing to do with tackles and interceptions.

If we were to apply Knutson’s formula to a comparison matrix between Mark Noble and Morgan Schneiderlin we would artificially inflate Schneiderlin’s tackles and interceptions numbers on the inverse basis of their possession % and artificially deflate Noble’s numbers on the assumption that he has more chances to tackle and intercept. The only problem is that here, between these two teams, that would be exactly wrong.

The problem is in the assumption. The assumption is that every time a team makes a pass it presents an opportunity to intercept. Similarly, that every time a player makes a dribble it presents an opportunity for a team to tackle. But not every team is trying to win the ball back with every opposition possession. Noble tackles less because his team tackles less. If you’ve seen them play you know that they are content with the opponents having the ball in their own half. Meanwhile, if you watch Southampton, they press. They try to force turnovers.

That’s just one example, there are others. In fact, Ted’s own regression analysis showed an R2 value of just .40. Only 40% of the variation can be explained by the model. That leaves a whopping 60% unexplained. I’ve done a fair number of regression analyses and I would probably never publish a .40 much less make some of the sweeping statements that Ted makes.

The thing about stats and especially football stats is that you have to keep them grounded in context: in the context of a team’s playing style, in the context of a player’s abilities and history, in the context of a league, the context of that league’s overall competition, and in the context of a league’s refereeing style.

I do think Ted is on to something. The idea that playing style matters to the end stats is bang on and you do see me taking into account a player’s contributions to the team’s whole. That said, possession only measures pass dominance. So, if I were to adjust anything for possession it would be passes. If I wanted to adjust defensive stats between two players, I might do something similar to what I have done above and compare those two teams’ tackles+interceptions ratios. Or even better, find out what the team’s tackle-interception ratios are in the League and then adjust for that.

But possession? I’m not even sure I like the possession stat as a “possession” stat much less as something I would use to adjust defensive output.




Technology, emotions, teamwork, and Özil’s ruthfulness: observations on the World Cup

1. The vanishing spray works

I can’t tell you how many times I’ve watched a Premier League match and complained about the referee’s inability to keep the wall back the required 10 yards. It’s a chronic problem and almost endemic to the English game at this point. Every match you will see players jostle, cajole, and creep forward once they do settle. Sometimes it’s so bad and the referee is so weak that he will march off 10 steps and then just allow the wall to set up 2 yards in front of him. By the time the kick is taken, the wall is sometimes 6-7 yards back.

But with the vanishing spray, the referee draws a line in the grass and the players can’t really encroach beyond that line. It’s brilliant and has worked in almost every case.


The one time it didn’t work well was when Holland were defending free kicks. They would constantly send a man to charge the ball down before the kick. Major League Soccer has been using the Vanishing spray for two years and it has worked wonders.

An odd side-story about the spray. The spray was invented by Heine Allemange, a poor Brazilian who gave up his family life in order to make this dream come true. He owns the patent for the mixture of butane and vegetable oil that makes the spray disappear. He joined forces with an Argentinian entrepreneur named Pablo Silva and formed a company called 9.15 Fair Play.

If you know anything about Latin American football politics then you know that Brazil and Argentina hate each other. The fact that the two countries joined forces to make Vanishing Spray has to be the feel good story of the World Cup.

Here’s hoping that the old farts who run the FA find a moment of clarity in their dark lives and approve the use of vanishing spray in the Premier League.

2. Technology has a place in football

Did you know that the average amount of time it takes to settle the wall and take a free kick is 48 seconds? And did you know that Vanishing Spray has decreased the amount of time between placement and free kick to just 20 seconds?

I say that mostly for the people who believe that technology will “slow the game down.” It won’t. Technology will speed the game up.

Another example is the goal line technology. There is no longer a need for referees to have a confab on the sideline whenever there’s a question about whether a goal should be awarded or not. With the new goal line technology, the referee is simply signaled on a watch-like device if there is a goal.

This is a major reversal from FIFA who, prior to world cup 2010, announced

The International Football Association Board is of the opinion that football will remain, for the time being, a game for human beings with errors on the field of play. We will try to improve referees but you will never erase errors completely.

I’m sure Bleater will say that the technology improved to the point where it made sense to implement it here in this World Cup. Maybe that is the case. I don’t really care. I really care that FIFA approved a technology that simply works and their old argument that “football should be the same no matter what level it’s played” has gasped its last fetid breath and expired.

3. Manuel Neuer is the best goalkeeper in the world

Sorry, Timmy! Sorry other guys. But Manuel Neuer is the best goalkeeper the world has ever seen. The amount of space he had to patrol in the German defense was mind boggling. He was exactly the kind of keeper that Arsene Wenger wanted Szczesny to be a few years back when we were playing our high-line offense. Szczesny did his best but never approached Neuer-like abilities. I’m pretty sure Neuer is a Teutonic god.

4. Germany understands football in a way that no other country seems to get

The German team landed in Brazil and immediately went to a purpose-built compound. The purpose of the compound was to build teamwork and judging by the way that the team earned their World Cup trophy, it worked a charm.

It wasn’t all sunshine and puppies, there were a few bumps on the road. I wrote about how Özil had been frozen out of a few games early in the tournament but Joachim Löw persisted with Özil in the lineup, to the detriment of Götze.

Watching the whole tournament it looked like Götze hated Özil. Perhaps that is a bit harsh, but there was clearly a problem playing the two of them together. And Löw dropped Götze instead of Özil. However, the young Bayern man got the last laugh and after a late substitution scored the game winning goal and probably goal of the tournament. It was a lovely goal as well.

But that whole team played as a team. Every player was played out of their natural position at some point in that tournament. Özil was shunted off to the left wing and still led Germany in Key Passes. Schweinstiger started his career as a number 7 and wore the 7 for Germany but he played defensive mid when Khedira, normally a defensive mid, came on to play box-to-box. Müller isn’t a center forward but he was simply amazing up front. Lahm played in three different roles as far as I could tell. Mertesacker was dropped when the team wanted to play a high line against speedy opposition, and then reintroduced at the end of the final in order to head balls away (which he did!).

It seemed to me like every single player sacrificed something for the betterment of the team. You have to credit Löw for that. He played this tournament and this collection of egos and talent about as perfectly as could be played.

5. Brazil need to rebuild

Brazil was a disaster. They were shockingly bad. If the Germans were organized and sacrificing everything for the team, the Brazilians were disorganized and selfish. They were the perfect foil for each other.

David Luiz was absolutely insane for the entire tournament. He would go wildly forward to charge down a man in midfield, bound forward to join the attack, and abandon his duties as a center back at almost every opportunity. He was also dirty, filthy dirty, running around kicking people and elbow smashing people at every opportunity.

The perfect illustration of this was his first 10 minutes against Netherlands in the 3rd place game. He kicked three people and intentionally elbowed Robben in the chest at one point. And while Silva gets the blame for fouling Robben which gave away the penalty (which shouldn’t have been a penalty but also shouldn’t have been just a yellow card) it was actually David Luiz who made that play happen. See, he came running out to challenge (read “foul”) Robben in midfield for an aerial ball. Consumed with playing the man and not the ball, Luiz lost the header and Robben smartly turned and joined the attack. Luiz then turned and jogged back as Silva was forced to foul Robben to prevent the goal.

Brazil reminded me of Arsenal about two years ago where we were disorganized and often wild in defense. Arsenal would routinely send both fullbacks forward and when we weren’t doing that then Vermaelen would come charging out of defense and try something crazy. When that happens, you get huge defeats. I’m not suggesting that Arsenal are perfect or that we’ve somehow overcome that problem, we still get beaten on occasion when we lose concentration and discipline at the back.

I wonder if there is an emotional component to this. For Brazil there is no doubt that their emotions got the best of them. Against Germany they were nearly in tears when they sang the national anthem, holding up Neymar’s shirt.

NeymarFootball demands discipline and punishes rashness. Defenders should stand their man up and stay calm, rather than diving in to try to win the ball back. Forwards need to have composure on the ball in order to score. So on. If you make a rash decision in this day and age, these players, who are blindingly quick and technically almost perfect, will eat you alive.

That lack of discipline and tendency toward rashness seems to me to be the reason why we are getting such big scorelines all over the world in world football.

6. Özil needs to learn how to be more ruthless

I love Mesut Özil and I am not intending this as someone who is joining the Özil bashing party happening over in England right now. I do not believe Özil is “nicking a living” nor that he’s overrated. I want to be very clear: as he stands, Mesut Özil is a fantastic footballer and worth every penny he’s paid. He has a silky touch and a vision of the game that almost no one in world football has at the moment. Even the dour Mourniho, known hater of beauty, had nothing but praise for Özil:

Ozil is unique, there is no copy of him – not even a bad one. He is the best number 10 in the world. He makes things very easy for me and for his team-mates with his football vision and the decisions he makes. Everyone loves him and sees a bit of Luis Figo and Zinedine Zidane in him.

That said, I think we can make observations about players that doesn’t tear them down but instead builds them up. No player is perfect, not even Messi. The mark of a great player is that they work on their weaknesses and the one thing I’d like to see Özil work on is his ruthlessness. He’s too ruthful. Put through one-v-one with the keeper he lacks that sort of killer instinct that Zidane had. He lacks that thing inside Figo that made him take over games and try audacious stunts.

Now, I’ve said this before and I’ll say it again: perhaps that’s our fault. By which I mean our expectations might be for Özil to be something that he just isn’t and never will be. Perhaps we want him to be more like Bergkamp and maybe we just need to accept him as the silky smooth operator in midfield rather than the hardened killer that we wish he was. Perhaps Özil will always be the guy who can and will win you games by simply laying on the right pass but who will never take over a game with an audacious strike from distance. 

But maybe, just maybe, Wenger can and will encourage him to come out of his shell a bit. To not be afraid to try something crazy and to be ruthless in front of goal. If Özil elevates his game that way, well, then £40m would have been a bargain.