Lies, Damned Lies, Statistics: Why Only Mugs Think Leicester Are Lucky

I love stats that tell a story, but I hate it when people claim a real story is wrong because the stats say it should be. I saw a tweet from a Spurs fan, who I won’t name, that said his team have been unlucky this season. His reasoning was this: “Spurs are top for many metrics used to measure best league team. They should be top, but aren’t.” He went on to say that Leicester had been lucky, and should in fact be somewhere between fourth and sixth in the table, and the reason they weren’t is that “luck plays a part.” spurs unlucky tweet

Well I’ve got news for him: Leicester finished top because they’ve won more games than anyone else, Spurs included, and over a 38-game season (36 at time of the tweet, but the League was won by then) that’s not luck, it’s playing better than everyone else. Let me rephrase that: it’s playing more effectively than everyone else, as ‘better’ is sometimes used to denote style.

Mr Spurs-Fan didn’t elaborate on the stats that showed his club should be top, but a popular one these days is ‘expected goals’, or xG. Basically xG is supposed to measure how likely it is that a particular goal attempt will result in a goal, based on a number of criteria. At its simplest the criteria is where the shot was taken from, but some models include how the ball was delivered to the person shooting, whether the goal attempt was by foot or head and which part of the goal was aimed for. Some models only include shots on target while others include all shots. None of the models in the public domain apparently include position of defenders and keeper, but there may be analytics nerds working on this. Arsène Wenger is apparently keen on xG, and was quoted (by Rory Smith in The Times) as using it to justify playing Aaron Ramsey in central midfield rather than wider: “If you look at his Expected Goals when he is in a central position, it is amongst the best in the Premier League.” Okay, Arsène. If you say so. But I hope you are basing team selection on slightly more than that.

Richard Whittall recently blogged to explain xG, using Arsenal’s 1-1 draw with Crystal Palace as an example. It’s a good read. According to most models, said Richard, from the shots both teams took Arsenal ‘should have’ won this match 2-1; that’s what you’d expect to see on average from the particular shots taken. But Arsenal didn’t win, so why not? Obviously there are a lot of variables – everything from how good the players are to whether the sun was blinding the keeper at a particular moment, or whether the wind got up in the second half, to the whims of the ref and linesmen, to whether Olivier Giroud stubbed his toe in the dressing room just before he put his boots on and didn’t have time to go to the toilet before he came out. The number of potential variables is massive, and with an expected difference of just one goal any variable could affect the match outcome.

But in general terms, and using this game as an example, I’d say that a major part of the reason Arsenal didn’t score as many as ‘expected’ is down to their tactics. Arsenal mostly like to play the ball around slowly, keeping possession until they create an opening that in their collective opinion is worth having a shot from. This can take a while, which gives the defending team plenty of time to get back into position. Arsenal fans will be very familiar with this. The outcome – not every time, but enough to skew the averages – is that often when Arsenal do shoot it’s often from relatively close range but under pressure from defenders and with the keeper well-positioned to make a save if needed. If you looked at the simplest xG model – where a shot is from – you could conclude Arsenal don’t score as often as they should from those shots. You might think Arsenal were therefore ‘unlucky’, or you might think the strikers were rubbish, and neither of these might be true.

I imagine xG is one of the stats that the Spurs fan I mentioned is using to justify his belief that Spurs are unlucky compared to Leicester. His twitter profile makes it clear he’s a gambler, so I hope he lost money by continuing to back Spurs for the title based on a belief that Leicester’s luck would run out.

As it happened someone then tweeted a graphic of the goals Leicester have conceded this season (up to 3 May) onto my timeline. This originated from Ted Knutson, aka @mixedknuts. I don’t know Mr Knutson, but I imagine from his twitter handle he has some sense of humour. Unfortunately this didn’t extend to indulging me by explaining why he believes Leicester are lucky based on this graphic, so I’ll have to try and work out his thoughts for myself. knutson leicester tweetsI waited politely, but in vain, for any further explanation. However, from the graphic below we can see that Ted’s model ‘expects’ Leicester to concede an average of 46.93 goals from the 489 goal attempts made against them, but in fact they conceded only 31. This is broken down further into shots from set-pieces, open play and crosses, throughballs, dribbles and ‘Other’.

The biggest variance from the figure Ted’s model expects is ‘Other’, but I don’t have a breakdown of what Other might refer to, so it’s difficult to say too much more there. Presumably it includes own goals and penalties, unless penalties are part of set-pieces. Leicester actually had no own goals for or against in the Premier League this season, so ‘Other’ remains a mystery. But I’ll delve into the remaining figures provided.  knutson leicester stats

Set pieces – expected to concede 14.84; actually conceded 9. Why might this be? Perhaps the Leicester defenders are very good at marking. Perhaps Kasper Schmeichel is well above average at positioning himself, especially when given time. Maybe Robert Huth kidney punches or pulls the hair of each opposing team’s most dangerous player at every set piece. There could be a dozen other reasons. Are any of these down to luck? No. Cheating in some cases, but not luck.fellaini-huth-elbow and hair pull

From open play/crosses and throughballs the variance is very slight, and the numbers are so small that trying to draw a conclusion is pointless. You certainly would not be able to state that Leicester were lucky based on these.

Similarly from dribbles, they conceded just once when they were expected by the model to concede 2.24 times. Maybe you could conclude their defenders are good at tackling dribblers, but the numbers are again too small to be meaningful – a single different outcome to one dribble in the whole season would have changed the ratio completely. You could also conclude in each of the above cases that perhaps Kaspar Schmeichel has just had a brilliant season, which again is hardly lucky.

Another telling stat on the graphic is blocked shots. If I’m reading it correctly Leicester blocked 33.1 per cent of shots attempted against them, compared to a league average of 28 per cent. Is this luck? If you never watch Leicester play, you might conclude that, but if you have watched them you’ll know that they make a lot of effort to block shots. Some teams don’t. Some defenders turn their backs on shots, but not Leicester; they jump in and, as the old saying goes, put their bodies on the line. Is that luck? No, it’s determination, will to win, being prepared to make a sacrifice for your team. If they keep playing like that they’ll keep blocking more shots than average. No luck involved whatsoever.kos turns his back

So I see no evidence of luck in Leicester’s defending at all. As regards their attacking, if xG predicts they’ll score fewer goals than they have, is that luck or is it down to breaking quickly and pulling defenders out of position so their own attackers are under less pressure when shooting? Is it luck, or is playing to their strengths and getting Vardy in behind defences with accurate long balls? Is it luck or is just being well-drilled at attacking set-pieces? If someone wants to show me where Leicester have definitely been lucky I might be convinced, but not so far.

What we need to bear in mind is that another factor preventing football stats models from being anywhere near perfect is the number of goals in football is very small compared to goals or points in almost every other game. A single random act can win a football match. That’s possible in rugby, though very, very rare. Theoretically perhaps also in hockey. It’s not possible at all in cricket, tennis, American Football, squash, baseball, basketball, badminton – almost every other team sport I can think of, not to mention the likes of golf, snooker, pool and darts.

It’s also hard to distinguish a clear dividing line when you’re counting football stats between signal and noise. So much happens accidentally: the ball deflects and ricochets in unexpected directions and with unexpected consequences. Corners go straight into the goal, poor shots are deflected in by defenders when they would have been saved, the ref gets in the way, bad shots become good crosses, assists and even goals can often come from mistakes… sometimes you get a defender under little pressure doing something horrendous, like Lee Dixon lobbing his own keeper from 35 yards. Merely counting all goals as equal and all assists as equal irons out differences, removes context and hopes the averages will take care of everything. If you want to believe that always works keep putting your money on ‘unlucky’ Spurs for the title.

So what use are stats? There’s a place for them in assessing players and games, but coaches who rely on them without taking other factors into account are going to get caught out (Arsène with Ramsey’s expected goals, perhaps?). A more realistic use so far is in building betting models. In some cases you do get enough information to see patterns that mean you can work the odds slightly, or have a better idea when it’s worth putting your money on. But you can be sure the bookies are equally keen to stay ahead of the game, or at least ahead of the 99.9 per cent of mug punters like the Spurs fan who thinks Leicester should be between fourth and sixth. Be lucky, mate.

Twitter: @AngryOfN5


10 thoughts on “Lies, Damned Lies, Statistics: Why Only Mugs Think Leicester Are Lucky

  1. Excellent post dispelling the idea that Leicester were lucky to win the league. I agree with the points mentioned about inadequacy of using stats to measure a team’s success across a season when there are a lot variables involved. But I stopped by just to put my thoughts on the Wenger-Ramsey-xG dig you had twice. What if Expected Goals is replaced with ‘more threatening’?
    Wenger: “Ramsey is more threatening when he plays through the centre.”
    “How would you say so?”
    Wenger: “He gets opportunities to be in better positions to score goals than he would from left or right wing.”
    “But can you quantify it?”
    Tactics are designed around players and are meant to complement their strengths. Maybe xG is just a loose metric which Wenger mentioned could be close to why he chooses some player in some position.

  2. Another Gooners so obsessed with spurs he has to have a pop.
    Don’t you lot give it a rest has your own team got nothing to write about?
    Here how about Arsenal same old same old 😘

    • Funny ain’t it.
      I also find it funny that the supporters of some clubs are making great mirth about Leicester beating Spurs to the title – they didn’t beat Spurs to the title, they beat everyone to the title!!!
      Or that Spurs somehow ‘blew it’. Spurs were never top of the league – it is the teams who were top of the league and above Leicester who ‘blew it!!!

      And the point itself: most sensible Spurs fans aren’t actually saying Leicester were lucky or don’t deserve to win the league (congrats to them). Most Spurs fans know that the slow start to the season hampered us right from the off. The point most Spurs fans are making is that goal-difference, goals scored and goals conceded are usually good indicators of a team’s likely finishing position. In this instance, Spurs have the best goal-difference, the second most goals scored, the least goals conceded, the most shots and the most shots on target and were generally considered by neutrals as playing the most exciting and attractive football (funnily enough, the index that usually makes most Goons think THEY deserve to win the league – least ways since Whinger has been the manager LoL). At the same time Spurs had to cope with more games, London derbies, and the managers/players of teams who had to play either or both of the protagonists expressing a preference for one to win the league and an almost rabid determination to stop the other. Let’s not pretend this didn’t happen! Oh, yeah, and the SKY schedulers deciding Spurs had to play a day, or more, later. So Spurs fans do think that by the usual indicators any team with those statistics would feel slightly unfortunate (which is not any comment or reflection on Leicester at all) and a little bit put upon by the other stuff. Only someone who is so blinded by partisanship or someone who is completely retarded would fail to see that!

      But not to worry… the overriding sense amongst Spurs fans is happiness at exceeding expectations and qualifying for CL, and excitement for next season – which will be interesting because so many rival fans, ironically given the nature of this article, think Spurs have ‘just been lucky’ this season😎

  3. Its true this article, Leicester deserve the league not just down to luck because as you say 36 games don’t lie. The point the fellow on twitter makes is a weak one because where you team faces shots doesn’t count in a game of football, only as you rightly said ; how many go in. The only argument Tottenham have ( and its been a point rightly made by arsenal over the years) is that they are the team who finished highest who played a brand of football more people find entertaining/ exciting, that is most goals, chances ect. Now whilst it is fair to make the point that entertainment is the whole point of professional football. Ultimately the team who wins most is the best team. As a fellow spud, I have to concede that Spurs do not deserve to win the title purely based on people’s perception of ‘entertaining football’ , just as Martinez doesn’t deserve to keep his job; for the same reason. The best team has won , the second best team ( we shall see who) hasn’t. Leicester have earned their gold patches like every other team in history. ( yes even United 10/11)

  4. I am a life long Spurs fan and I wish to offerLeicester my congratulations, you have been magnificent and thoroughly deserve the title.

  5. Fell asleep halfway through but woke up to write this comment.

    ‘Pointless article. Spend the time on figuring out why Arsenal are total and utter dissapointing dog shite, not a team that topped all the stats on goals scored, conceded, chances created, league top scorer, most running, etc (that would be Spurs)’

    That is all.

    • What do you get for topping the stats tables ? Nothing. The only stat you have to worry about is the one that measures who wins it. Points make prizes after all.

  6. This is a great article, and I 100% agree. I would say Leicester “rode their luck” a lot, not saying they are lucky, they are well drilled, but they got quite a few decisions in the year where in reflection, were possibly wrong in their favour according to a football 365 weekly article with a ref (I have never seen this in previous years, so don’t know if it common place for the champions). What I mainly mean by rode their luck was playing football a lot without the ball, allowing teams possession in the Leicester half and relying on the counter attack – this though is not actual luck, it is a tactic and one I like, after all, what is possession without an end result, I bet if you looked at the stats for goals against time with ball they would be top of Europe. They won a lot of 1-0’s, but again, that is a sign of a well drilled defensive unit. To say they were lucky is not wholely untrue, but to imply they are the only team to win the league who had luck on their side is a nuts, almost every football player and pundit will admit that winning the league takes the odd bit of luck.

    Anyway – rambling now, so to summarise, if Leicester were “lucky” it was of their own making, and is probably no more luck than any other team in history had to win the league. Whats the saying “The harder I train the luckier I get”, or “you make your own luck” or the one I heard of late “you have to work hard to be in the positions where luck can find you”.

    As a spurs fan, Leicester did well to win the title, and although I don’t agree the best football team one the league, I think the team with the best spirit and the best all round game plan won the league. The table doesn’t lie, but is like many other statistics, counting one thing (points) in isolation can skew the truth. However, points win prizes!

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