Men on posts at corners

[MJG]

Couple of good articles on the age old question or shout from fans....why was no one on the post

http://statsbomb.com/2017/03/men-on-posts-and-starting-fires/

I mentioned on Twitter recently that while I try to avoid disagreements when I am in a room with traditional football people, the one thing that is most likely to set off an argument is the topic of men on posts. Today I want to explain why that is the case, while covering a variety of other topics along the way.

Men on Posts
I swear to you, this topic comes up almost every week on highlight programs and game commentary. It is perhaps a bit less prevalent than discussion about the failings of zonal marking here in England, but it's an old favourite for the back-in-my-day commentator crowd. In 99.99% of the cases, it is also nothing but dead air and might as well be replaced with any other cliche that also gets spouted by the same commentator crowd. (We need better, smarter commentators, but that was a topic for a different day.)

My perspective on men on posts is that I almost never use them for defensive set pieces. There are a lot of reasons for this, but the basic principle is that I prefer active defending to passive and this takes one or two players completely out of the play where their only job is to act as last resorts. Now this isn't to say that I would never put men on posts. There are specific teams and situations where they are beneficial, but those are fairly unusual.

However, my preference for set piece defense isn't usually what starts the argument. Once the subject is broached, the conversation usually goes like this.

Me: "How do you feel about men on posts when defending set pieces?"

Traditionalist: "Oh, I would always have a man on [near¦far] post and sometimes a man on the other one."

Me: "Why?"

Trad: "Because [reasons]."

Me: "Okay, but how do you know?"

And this is where things invariably get awkward because usually they "know" because someone taught them this was the correct way to do things. Or possibly some anecdotally negative experience like, "we didn't have men on posts in this game, and the opposition scored a goal in the corner," changed previous behavior and now they protect against that scenario.

The problem here for someone like me is that when analysing most topics in football, I start back over at base principles. How do I know something? Well, I studied it. I typically take a large amount of qualitative and/or quantitative data, break it down, and then look at the outcomes to see what's there. Then I ask follow-up questions and pick at the results some more until I am comfortable I understand what I'm seeing.

This doesn't mean I am right. It's not about being right. It's about being knowledgeable in an area that is important*. And it means I have a foundation upon which to have conversations. Conversations and arguments tend to illuminate what you do and do not know, and highlight areas for further investigation. This is important, especially in football which, if we're being totally honest, is a game that we really don't understand very well right now. This includes most of the ranks of professional coaches around the world.

*important to the performance of your football team, at least. In the greater scheme of crazy world events, understanding set piece defending matters not a nip.

It also doesn't invalidate knowledge learned from years of working on the pitch. It just means that if you believe a thing to be true, you need to explain how you came to those conclusions, and the reasons need to hold up to scrutiny. If they do, great. If not, let's study the issue and see if the accepted wisdom the you believe to be true is correct.

So yeah, when you ask questions about how someone "knows" a thing, and maybe question the validity of that knowledge, you can cause problems. But the fact of the matter is, we should be doing this constantly inside of clubs because it leads to valuable research that can change behavior and develops more effective styles of play.

A goal in the Premier League is worth something like £2M. How many of those do we leave on the table because someone's knowledge is outdated or just plain wrong?

(For what it's worth, on defensive corners, my players have poo to do instead of loafing around, leaning against goal posts. We save that sort of behavior for useless analysts, as it's the footballing equivalent of mooning the queen, donchaknow?)

A Good Question?
Someone noted over the weekend that Manchester City seem to prefer outswinging corners these days to inswingers. This is notable for two reasons.

First, a few years ago under Roberto Mancini we were told that City started using only inswinging corners because someone in the team had done a study and found that inswingers were more effective at generating goals.

Second, this switch to outswingers seems a direct contradiction to research previously done by this exact same team.

Odd, no?

James Yorke started poking around the data a little bit, as we tried to figure out what data they looked at to come to whatever conclusion it was that changed their behaviour. This lead back to a far more important problem that is often overlooked:

What question were they trying to answer?

It certainly doesn't seem to be "which delivery is more likely to score goals?" since that either leaned toward inswingers or was inconclusive, depending one what data was used.

However, what James did find was that outswingers were far more likely to be completed to a teammate. So if they were trying to answer the question of "which delivery is more likely to let us keep possession?" then outswingers would make a lot of sense. Given this is a Guardiola team, maybe that's what he wanted to know, especially since he is typically far more concerned about defensive shape when attacking than corner production.

Is that a very valuable question to bother answering is another issue entirely. Given elite corner execution can produce expected values per corner of .06 to .08, while average corner values are .025 and average possession values for most teams are in a similar or even lower range, I'm not so sure.

This is where the difference in counting and percentage stats comes into play versus stats that attach value (like the xGChain passing networks from StatsBomb Services). As football analytics matures, it moves more and more toward the value end of the spectrum, since that uncovers behaviour and strategies we really care about. Failing to incorporate these elements into team research can result in suggestions that actually makes team performance worse.

I'm not sure this is what happened at City – as I said, we're guessing at literally everything while we wonder why they are doing what they do. It's just a concept to keep in mind when generating research projects and then applying them to team behaviour in the future.

English Coaching and Commentators
Circling back to the commentators we hear on Sky, BT, and BBC every week, it frustrates me that the people talking about the game now were generally players that grew up in and played a style that has been completely refuted by the modern game.

The traditional English style of play Does. Not. Win.

If it did, we'd see far more English managers present in the Premier League, and dotted around Europe's elite. What we actually see is a complete dearth of English managerial talent throughout the ranks of the football league. The Premier League gives zero fucks about this, but it is worrying to the FA and generally to the lower tiers of the football league as well.

I've asked questions about how coaches in England are supposed to learn more successful styles of play, and the only real answer seems to be to beg, borrow, and steal internships either at teams with successful foreign managers (extremely difficult to do, even with elite contacts), or learn a language and do your coaching education abroad. Good luck with that in a post-Brexit environment!

This circles back to FA coaching courses, which have been revamped (again) in the last year. I did the class days for England level 2 badges almost exactly a year ago, and while I generally liked the process they used to teach you how to think about coaching, I thought they were also lacking in certain areas. The section on pressing was largely ineffective and dismissive, where the instructors were telling us it was fad-ish and existed before. Technically this was true, BUT

    That ignores the fact that the current iterations of pressing come in many varieties and are substantially different than what you saw from the 70's through the 90's
    Pressing variations really matter for evaluating top level tactics and play, which means they really matter for top level coaching
    The instructors, who were otherwise quite good, displayed no real understand of this particular topic. Or really of shot locations and effectiveness. Which, if we're trying to train and develop better coaches and in turn better players, is probably a big deal.

Maybe this type of subject material doesn't matter at level 2, and I was expecting too much, or maybe English coaching education is still struggling dramatically to overcome decades of ineptitude to catch up with modern times. I honestly don't know.

Which finally leads me back to the current crop of commentators. Aside from Carragher and Neville, who clearly put a lot of research and work into their craft, the commentators currently discussing football on television generally don't understand modern tactics. How could they, when the tactics they were brought up playing were bad, and the coaching education failed to correct for that?

Nor do they have an analytical mindset, which would help to educate viewers on the reality of the game versus the perception. They commentate on games in 2017, but were almost exclusively trained in England, and brought up playing a style that almost doesn't exist any more at the top levels of play.

So what are they there for? The occasional interesting anecdote about mentality and what players feel like before a big game? To provide a constant stream of footballing cliches that provide no insight and are rarely relevant to the moment at hand?

We get nothing of interest from so many talking heads on television. No funny anecdotes about current players or managers. No tactical insight. No statistical insight. No points about technique and detail about what a player could or should have done better.

Half of the matches I and many other viewers watch each week have foreign commentators. I almost never feel worse off because of it. And THAT is a take away that should shake everyone involved in the production side of football, right up to the top levels of Sky and BT Sport.

[MJG]

2nd article

http://frontoffice.report/defending-corners-prospect-theory-and-why-sports-analysts-need-to-think-like-lawyers/

Defending Corners, Prospect Theory, and Why Sports Analysts Need to Think Like Lawyers

March 23, 2017 By Richard Whittall

I am admittedly biased toward analytics pieces that involve some form of media criticism, so I was intrigued this past week by Ted Knutson's Statsbomb post on the received wisdom—repeated ad nauseam by almost every English colour commentator in the game—that teams should always post defenders on the posts in corners.

Knutson argues that putting defenders on the posts is like an extremely expensive insurance premium for a fairly low probability event. You're taking two guys out of the defensive mix and, presumably, you make them less able to help facilitate an effective counter.

But what irks him most is that no one in football media is willing to take the time to question why so many clubs today don't do it, if it is so obviously effective:

    So yeah, when you ask questions about how someone "knows" a thing, and maybe question the validity of that knowledge, you can cause problems. But the fact of the matter is, we should be doing this constantly inside of clubs because it leads to valuable research that can change behavior and develops more effective styles of play.

    A goal in the Premier League is worth something like £2M. How many of those do we leave on the table because someone's knowledge is outdated or just plain wrong?

I am, at the moment, still working my way through Michael Lewis' book The Undoing Project, on the pioneering work of behavioural psychologists Daniel Kahneman and Amos Tversky. It's a kind of more narrative driven summary of the ideas that you should almost certainly read first in Kahneman's popular masterpiece, Thinking: Fast & Slow, but there are a few highlights, and one of them is the story of the development of Prospect Theory.

The theory essentially holds that we tend to overestimate low probability events and underestimate high probability events in making choices between situations that involve an economic loss or a gain (there is a very simple summary of the theory here). Moreover, we don't view potential gains the same way we view potential losses; we would rather not lose $20 from our wallet than find a random $20 in the street.

So with that in mind, here is an entirely untested theory I have on why many coaches would rather post two guys on the posts during corners.

Let's say the corner comes when the score is 0-0; we all know this is a vital moment in a football match. Goals are rare in football, and conceding a goal will entail your team must score two to have the greater likelihood of earning all 3 points. So conceding a goal at this point carries a strong negative psychological burden, particularly when it comes to set pieces in your defensive final third.

I'm also willing to bet that when most of us visualise a goal scored from a corner, we see in our minds a towering central defender or striker rising majestically in the air to head the ball into the top right or left hand corner. Something like this maybe:

https://www.youtube.com/watch?v=x48aVBsEOmI&feature=youtu.be

It's natural that, when we see this kind of goal, we think "If they would have only put defenders on the posts, they could have headed those chances away." When people think about defending against corners, it's this kind of thing they're worried about most.

What those coaches and commentators can't see, at least without the benefit of data, is the actual frequency of these towering free headers, and whether that frequency goes up or down if you take the two guys standing around at the posts and involve them in a more active defensive set up. Instead, they have a very powerful mental image of a conceded goal from a set piece, along with all the bad stuff that comes with it.

And so, perhaps out of fear and familiarity, coaches not only vastly overestimate the likelihood of these kinds of chances occurring, and in doing so leave themselves more open to less obvious scoring chances, perhaps from a second or third ball, than they would if they had more active defenders.

I want to use this example to make maybe one of the most important points about soccer analytics—sports analytics, even—that I can, especially with all the near constant talk about the importance of communication between analysts and coaches/players/media.

Stats people will know that producing a study of the effect of using defenders on posts for corners is not difficult, relatively speaking. What is difficult is convincing a risk/loss averse coach or commentator that they should ignore their instincts and trust a pile of data. These are strong, predictable psychological biases that are difficult to simply waive away in the face of even the strongest evidence.

This is why, in my opinion, the job of analyst is not merely to be a good scientist, or a good  designer of compelling visualizations. They also have to be good lawyers.

Good lawyers know that it's not not enough to simply present the facts of the case to convince a judge and jury; they need to make their argument with persuasive rhetoric, repeated emphasis on key points, and a strong, plausible narrative (this also explain why some of the more successful sports analysts I know are former lawyers).

If I were to make the case for taking men off the posts for example, I would want to work closely with my performance analyst to come up with a series of videos, convincing instances where teams that posted players on the posts conceded sloppy goals, or failed to initiate an effective counter. I would want to package my case as part of an effective, top to bottom powerpoint presentation.

And, in making my case, I would want to work with prospect theory, not against it. You have to convince your coach not only that posting guys on corners doesn't prevent as many goals as you think, but that posting guys on the corner is the riskiest defensive maneuver on the books.

Sure, your dataset will be the foundation of that argument. But it doesn't speak for itself (and neither does a linear regression or pretty viz). You need to make a case.

On a happier note, not everyone who works in English football media is as obtuse as our imaginary co-commentator. This, by Jonathan Liew, is one of the best examples I have seen recently of a journalist making effective use of data to make a very compelling point about Tony Pulis' alarming habit of shutting up shop at 40 points. Well worth your time. We need more Liews and Ingles plugging away.

[The Enclosurite]

We need to put a man on the side touchline to stop the ball going for a throw in when we take corners!!

[toshes mate]

Invariably, statistically and reality speaking, if you don't have a player on the post and a goal is scored on that side of the goal, the argument for a player-on'the post is validated.  The same argument is trotted out in reverse if a goal is scored and you did have a player-on-the-post who could have more usefully employed elsewhere.  I just avoid circular arguments and say 'we have got to be better at defending - period......

There's money to be made in research, analytical science, the legal profession and just about anything else we can have a good old argument about.  But, why oh why, MJG, do you use the US version of the word defence (which the FOF software will pick up every darned time, dammit).

[f321ffc]

 We need to leave a man on the halfway line when we defend corners.

[toshes mate]

We need to leave a man on the halfway line when we defend corners.

The way we take corners we need ten men on the halfway line.....

[MJG]

But, why oh why, MJG, do you use the US version of the word defence (which the FOF software will pick up every darned time, dammit).

I'll take the blame for most things if I write them, but this two articles are not mine.they are just cut and pastes.

[Carborundum]

I've been watching under 12 eight a side recently.  Great fun and some of the corners taken put our first team to shame.  Suspect that the reason men on the post endures is that at a tender age it's a lot easier for a coach to instruct players on that specific position rather than spout about "defending actively"

At under 12 level it seems to work a treat.  The team with the best plan and/or ability to stick to it seems to win.

[dannyboi-ffc]

Bloody hell Mike, where do you find these people.  How on earth can so much need to be said about a bloke on a post for a set piece lol.

I think you do need one. Whichever post the keeper decides he feels more comfortable with. For me it's like wearing a seat belt when driving. If you drive perfectly and slowly and there's no other cars on the road then I suppose you can get away without wearing it but it's a precaution taking to protect you for the unforeseeable. Same as a player on the post. If you have everyone man for man there's a 50/50 chance one of them will lose their man or lose the header. And that extra insurance that shouldn't be necessary might just be the precaution that protects your goal.

The bigger issue for me is clubs (and Fulham do this every time and it drives me insane) is bringing every man back to defend corners. Why on earth we don't leave someone on the half way line to get the second balls when it's cleared I don't know. The ball just comes back again if there's no one to counter with.

[BestOfBrede]

We need to leave a man on the halfway line when we defend corners.

The way we take corners we need ten men on the halfway line.....

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[Apprentice to the Maestro]

Thanks for posting these articles on an interesting topic.

I am for analytics done well, in particular when they 'attach value'.

Unfortunately I found these writers very full of themselves, keen to have a go at the television pundits and English coaching but in the end rather short themselves of any convincing data to support their promoted approach.

I am sure that some quite complicated analysis, more than these two seem to think would be sufficient, could enlighten us on the relative merits of inswinging vs. outswinging corners or men on the posts vs. active defenders but both seem a long way from delivering on that. Their argument seems to come down to "unimaginative traditionalists have men leaning on the posts whereas we modern progressive thinkers have active players" which is no advance on the argument they deride.

There are several other issues in defending corners that need thought. What about the other modern fashion of bringing all the players back to defend a corner? Is there evidence to show that that is effective in defending corners? What about its effect on counterattacks?

What about that other player who is generally standing about doing very little during corners in the modern game: the goalkeeper?

And what should a team like Fulham do when their players are generally shorter than the opposition?

[filham]

I After reading all that I am beginning to think that Stats Boy will be soon deciding team tactics as well as the suitability of new players.

[nose]

good topic
for what it is worth IMO a player on each post plus one on the half way line every time.

[toshes mate]

And what should a team like Fulham do when their players are generally shorter than the opposition?

Run between the opponents legs.....

[MJG]

I After reading all that I am beginning to think that Stats Boy will be soon deciding team tactics as well as the suitability of new players.

Fulham had match analysis and stats for a very long time and use it for all of this stuff. Long before the current regime came in.

[St. Andrews White]

I will admit to being that bloke who shouts "On the posts Fulham!!!" at every corner...
You're articles are however very interesting, and do give a different perspective.
For my penny's worth, a man on the post is worth it; some people you just can't defend against when they really want to score. Occasionally it is that simple. As DB said, it's very much like a seatbelt - if everything goes well then it's unnecessary, but there are some things you can't account for. Plus given how crowded the box is, it can be hard to track a man who is phenomenally good at putting them away.

I'm not saying I'm right either, just my thoughts!

[YoungsBitter]

Thanks Mike, really good reads, especially Knutson's.

I thought the comments about coaching the press were revealing, as well as the general comments about the lack of trust in the game for data. Just looking at the comments on here give you a clue as to how fraught that is as a subject, and on here we are amateurs. It must be mind numbing to be in the game on a professional basis with so much money at stake and there to be so much push back on using data.

On corners I think the key issue is how active the keeper is. It is also revealing how low the probability of scoring is from corners yet I like everyone always think its great if we get one and after the last 3 years crap myself when we concede one.

[MJG]

Another good article on corners

https://www.theguardian.com/football/blog/2017/mar/27/in-defence-of-the-corner-a-much-maligned-set-piece?CMP=share_btn_tw

Football fans have a curious relationship with corners. For a set piece that, according to Opta, leads to a goal only 3.2% of the time, they don't half get excited about them. A stadium invariably gets louder when a corner is given and there is a heightened sense of anticipation or fear depending on who you are supporting. Yet, never before has the prevailing opinion on this particular set piece seemed more scathing, with many fans' forums containing a thread with a title along the lines of "Why are we so bad at corners?" and the phrase "You've got to be able to beat the first man" right up there at the top of the co-commentator cliche bingo list. But is it really true that, when footballers' technical ability has seemingly improved in the past decade or so – particularly from an attacking perspective – their ability to knock a ball 25 yards into the penalty area has deteriorated?

In the past five seasons, the Premier League's goals-from-corners ratio has barely moved, varying between 0.32 goals per game to 0.38. It's probably fair to assume that this figure isn't wildly different across Europe's leading leagues or in international football. So, if there hasn't been a sudden drop in the effectiveness of corners in creating goals why is it that we now appear to have such a dim view of them?

A starting point could be that our opinion is perhaps coloured by the volume of football on TV. If a corner only leads to a goal 3.2% of the time it's inevitable that most corners aren't going to leave a good impression and the more of them we see the more entrenched that negative view is going to get. And then there is the oft-parroted view that professional footballers trousering loads of cash at the very least should be able to beat the first man. This is where there is a serious misunderstanding by many fans about what constitutes an effective corner. There is a huge difference between phoning one in and delivering a dangerous one.

If you look at footage of corners taken in the 60s and 70s there was more of a tendency to loft the ball into the box. With this method, unless you miskick horrendously, you will almost certainly beat the first man but you will have very little dip or pace on the ball. That was fine in an era when you could put a bit of physical pressure on goalkeepers who still preferred to catch the ball (meaning they could be easily nudged into dropping it), but these days that kind of corner just doesn't cut it, with keepers preferring to punch to lessen the chance of making a handling error and referees affording them more protection.



This means that for a corner to really cause panic in an opposing defence, one of the best areas to direct it is just behind the first defender usually stationed at the front of the six-yard box. It's a particularly tight target, similar to aiming for the top corner of the goal when taking a direct free-kick. Not only must they get zip and bend on the ball, they have to make sure they don't overhit it nor deliver it too close to the keeper. And with the first man usually standing about 20 yards away, to be effective, the ball needs to dip just after clearing this player to unsight defenders and give those attacking the ball the best chance of nipping in front of their opponents to divert it at goal. Nacer Chadli's delivery for Craig Dawson's first goal for West Bromwich Albion against Arsenal earlier this month was devastatingly good and Arsène Wenger was right to point this out whatever the deficiencies in his defence. Mastering dip at a specific distance is a difficult skill – it is probably easier on a free-kick when you have a wall close by to help calibrate it. There are so many factors to consider when delivering a corner and a variety of styles that mean some are more difficult than others. A front-post corner is probably more likely to be cleared by the first man than a back-post one, for example, while an outswinger gives a goalkeeper less chance of collecting it but is probably not as dangerous as a fizzed inswinger. Perhaps the pursuit of perfection means that, say, four out of 10 corners don't clear the first man, but of the six that do the chances of scoring from them are much greater than clipping in 10 safe ones.

Some players, such as Brighton's Anthony Knockaert, above, approach the ball at an acute angle in order to avoid running on the 3G surface next to the pitch.

There are other reasons the corner is given a rough deal. Considering the amount of money spent by leading professional clubs on ensuring they do everything they can to give their players the best possible chance of performing well, when it comes to making them feel comfortable in their own ground when taking a corner, they still leave a lot to be desired. Beyond the touchlines at Old Trafford the turf runs off down a slope. Corner takers there have to trot up a hill before delivering their kick. Other grounds have similar obstacles and some still don't have the optimum space for a run-up – certainly not as much as would be afforded on the training ground. In the past decade most clubs have introduced synthetic turf beyond the touchline to prevent wear and tear from assistant referees and substitutes. This means corner takers can often be put off by the feel of the surface changing beneath their feet as they are about to strike the ball. And while it is easy to perhaps hold little sympathy for footballers over what appear to be minor inconveniences, it is odd that there are still improvements that could be made in this area at major clubs who try so hard to make marginal gains elsewhere.


Another factor could be a change in the tactical approach by some clubs towards defending corners. In the past decade, there has been a growing trend towards not putting a player on both posts, with a preference instead to leave one or both unguarded. One of the reasons for this system is to use a corner conceded as a platform from which to spring your own potent counterattack. André Villas-Boas and Brendan Rodgers, both known for bold tactical experimentation (with varying degrees of success), were among those to first use this set-up in the Premier League. They believe opposing teams are at their most vulnerable when taking a corner and there is evidence to suggest they are right. This season, Liverpool have conceded numerous times immediately after their own corner-kicks. So it is little wonder now that many teams are often reluctant to pack the opposing penalty area in the way they would in the past, thus decreasing their chances of scoring.

That's not to say there aren't occasions when players aren't just useless at them. In recent years, a couple of comedic efforts from Wayne Rooney and Iago Aspas have done for the corner's reputation what Jar Jar Binks did to George Lucas's as a celebrated director. Taking a good corner isn't the hardest thing in the world but nor is it as easy as many casual observers assume. Perhaps we should be a little less hasty in bemoaning the state of this much-maligned set piece – and appreciate a good corner a little more than we currently do.

[toshes mate]

A seriously better article, in my honest opinion, than that earlier, with no lack of amusing asides and some ground we have recently covered on these boards.  I noticed how good Scotland were with some of their corners yesterday without actually getting the ball in the net (except when disallowed).  Perhaps most coaches are playing the percentage game when a) letting defenders give corners away without too much worry, and b) not throwing every player into regimes that get corner taking down to a fine art.  Perhaps we need touchline and penalty corners introduced as in field hockey just to get threats back into the attacking game.   

[MJG]

Go to to 1:42 and short chat about corners covering much on here

http://www.bbc.co.uk/programmes/b08k2cvt