Statistics. - How do we interpret them?

Liverpool Football Club - General Discussion

Postby bigmick » Sat Jan 03, 2009 1:05 am

I got to thinking whilst we were talking about zonal marking and Owzat our stats man (who from this quarter anyhow is much appreciated) produced those figures which dispelled any notion of us being the hardest of all teams to score against, or appeared to anyway. Then you got posters saying "yeah but I look with my eyes mate" which to be fair is exactly what I say as well when the stats don't back up my point. On the other hand, if they do then quite obviously you can't argue with the stats, they are concrete proof.

There is something though I think in the idea that very often the stats don't tell the whole story. If for instance we concede less goals from corners than any other team in the league is it fair to conclude that we defend corners the best? What if we play Hull at Home, get 16 corners and score from one, whereas they get 1 and don't score from it? Does that mean we defend corners better, or that we simply get more of them? Wouldn't it be a better indicator if there was a stat which gave in percentage terms how successful a team was at defending corners? Perhaps you could say that a team has a success rate of 98% at defending corners, therefore they are unequivically the best at it.

Similarly, from the posession stats we can work out how much a team has the football in each match. How long does the team need the ball then to score a goal, are we actually statistically more likely to score a goal when Torres plays, when Gerrard plays off the front man, when Kuyt plays up top etc?

S@int provided some staggering stats on Alonso (albeit in the wrong thread  :D ) and can those stats be true/acurate/indicative? Most of us have said from our own eyes that Xabi's form had dipped, and that he is now playing better (much better). But can the difference be THAT much, and if it is, why is it? Why is he completingso many more passes? Is it because he is playing so much better, or is because we are playing 4-4-2 sometimes and Masherano is no longer around to dilute the posession he recieves, is it because he's taken our advice and moved out of the pocket, or is it because he simply is playing that much better? I simply can't believe it's solely the last reason, so there has to be other factors.

The Mrs's brother (my BIL) is the head coach of the USA volleyball team. They won the gold at the Olympics in China which was lovely, and I've had some fascinating conversations (for me, probably not for him :D) with him about the uses they make of video, stats, probabilities and the rest. There is no doubt in my mind that football has a way to go in this area, as human beings tend to have "go to" tendancies under pressure. The in depth study of stats and the anaysis of the results could just provide the edge. Thereis far more to it IMHO than studying which way a penalty kicker generally hits it, or studying patterns from corners.

Footballers have patterns which they no doubt don't even realise themselves. Likewise, teams have patterns in defence. It would be nice if someone could produce stats which go beyond the "number of minutes per goal" despite the fact it is obviously superior as a stat to number of goals per appearance.

I'll leave it there as I'm waffling, but IMHO (although I accept it won't be to many) it's an interesting subject. No doubt the basketball fella who locked horns with me a couple of days ago could shed some illumiation on the whole subject, as the American sports seem to lead the way in such studies it seems to me.
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Postby Quadrophenia » Sat Jan 03, 2009 1:09 am

Only one stat matters. The scoreline, that's the only stat that will be taken into account in years to come.

Will people in ten years be arsed that Arsenal twatted us in the 01 cup final? No because the scoreline says 2-1 to Liverpool. Will people in ten years know Liverpool :censored: hammered Stoke this year? No because the scoreline says 0-0. That's what goes into the history books, not the meaningless stats about possesion, shots on/off target, successful passes. :censored: waste of time.
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Postby Sabre » Sat Jan 03, 2009 1:12 am

A succesful pass is one that ends up in the receiving player and is not intercepted. That's what the stat get. The stat DOES NOT GET the quality of that pass, the danger that created that pass, and whether it was the RIGHT pass, which are the things that naked eye tells us. If anyone is able to argue this last paragraph, please do so.

:D

Good you have opened a thread to discuss this.

My stance is simple:

* I'm grateful to the WORK Owzat makes gathering and crunching numbers. It's a credit for the forum

* I'm skeptical with many of his interpretations.

For me, playing well, is linked with the notions naked eye will tell us  was that the right pass? was it a dull pass? was he slow? you know what I mean. A succesful pass stat, is counted +1 if it's received by the player you send the ball. Does it get that stat whether the pass was the best option? no.

So don't use the succesful pass to say someone is playing better.

However, not all stats are bad. If we see Mascherano makes A LOT OF TACKLES, certainly that is good. But if we see he doesn't score goals or makes assists, that means nothing. He's role is not about that.

Similarly, the stats say that Liverpool is the best team in England. Does that mean that posters haven't to say there are things that we could do much better? No, in fact, it's even possible to say we're not playing well, regardless what that stat says.
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Postby bigmick » Sat Jan 03, 2009 1:14 am

Could I also say as well that I hadn't seen the disagreement between S@int and Sabre while I was typing, and as they are arguing it out in the other thread there's no point in doing it as well in here. I'll give you another stat, clean sheets. Is the goalie who keeps the most clean sheets performing the best, or is he playing for the team who has a decent defence? Clearly Pepe wouldn't keep the most clean sheets if he was playing for Blackburn, but then again we also all know he is arguably the best keeper in the league. Not though as a result of stats, just because you can see it.

One of the things he is good at, is stopping shots from distance. Statistically, how mnay shots does he concede from shots outside the area? 3%, 6%? Feck knows but somebody should. Paul Robinson concedes loads, I don't know from stats but he gets beat from distance everytime I watch him. Lack of spring I think, too heavy on his feet.
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Postby account deleted by request » Sat Jan 03, 2009 1:14 am

Imo stats are good indicators not always to be taken at face value. (BTW I put those stat in there because stu was having a go about the value of stats not to prove or disprove anything with Alonso)

Stats that back up observation are certainly of more use. If you think you are conceeding a lot of goals in a season for example, and then look and find that you have conceeded twice as many as last season. There is a strong likelyhood that your observation was correct. Yes, there may be reasons WHY you have conceeded more, which just makes the stats all the more interesting.

A common stat is that the further up the pitch you play the less successful passes you make. This may mean that as you play further forward your skills desert you or more likely the further forward you play the more difficult it is to play a successful pass...... your choice. Which is where common sense and knowledge of football comes in.
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Postby Sabre » Sat Jan 03, 2009 1:16 am

Mick no worries, I think it's a healthy discussion, as stats are very fashionable these days. Nice idea of a thread, if you ask me.
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Postby bigmick » Sat Jan 03, 2009 1:18 am

Quadrophenia wrote:Only one stat matters. The scoreline, that's the only stat that will be taken into account in years to come.

Will people in ten years be arsed that Arsenal twatted us in the 01 cup final? No because the scoreline says 2-1 to Liverpool. Will people in ten years know Liverpool :censored: hammered Stoke this year? No because the scoreline says 0-0. That's what goes into the history books, not the meaningless stats about possesion, shots on/off target, successful passes. :censored: waste of time.

Totally disagree Bill and you're missing my point. Stats in the aftermath are pointless but do provide some useful information which might help you to improve.

How many goals have we conceded when the ball is crossed in from the left in a set piece, as opposed to the right? The numbers won't be the same, and it won't be a coincidence if you measure it over time. On one side or the other, it's quite possibile the front zone works better.

I'm talking about the use of stats not on our team, but on others.I'm talking about the predictive, probability area of stats, and the use of them to anylise performance. they aren't a waste of time there at all.
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Postby bigmick » Sat Jan 03, 2009 1:26 am

Back to the brother in law, and their extensive use of computers, stats and probabilities. They played against the tournament favourites in the Olmpic semi's, and they game plans worked out for each player. They reckoned that based on probabilities from extensive monitoring, if player A is recieving serve, the pattern that will follow when the game is tight is that the setter (usually a short, for some reason quite hairy bloke at the front who flicks it up for the big guy) is going to set it for player B. They know the names of the players but feck knows, they're Brazillian so we'll call the big guy Pico for the sake of demonstration.

They have a read on Pico which says come the big point, two games all, 22-22 in the decider he likes to go cross court for the power shot or whatever it is. They put two blockers on him and force him to turn his body and try for an unfamiliar down the line thing, and he dumps it onto the net. Tennis players will do it as well, they'll know that at 2 sets each, 5-5 and deuce that such and such is going to serve it down the line. They don't guess, they know what the probability is.

In this area, football has much to learn.
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Postby Quadrophenia » Sat Jan 03, 2009 1:26 am

bigmick wrote:
Quadrophenia wrote:Only one stat matters. The scoreline, that's the only stat that will be taken into account in years to come.

Will people in ten years be arsed that Arsenal twatted us in the 01 cup final? No because the scoreline says 2-1 to Liverpool. Will people in ten years know Liverpool :censored: hammered Stoke this year? No because the scoreline says 0-0. That's what goes into the history books, not the meaningless stats about possesion, shots on/off target, successful passes. :censored: waste of time.

Totally disagree Bill and you're missing my point. Stats in the aftermath are pointless but do provide some useful information which might help you to improve.

How many goals have we conceded when the ball is crossed in from the left in a set piece, as opposed to the right? The numbers won't be the same, and it won't be a coincidence if you measure it over time. On one side or the other, it's quite possibile the front zone works better.

I'm talking about the use of stats not on our team, but on others.I'm talking about the predictive, probability area of stats, and the use of them to anylise performance. they aren't a waste of time there at all.

Mick with all due respect fella, don't waste any more time trying to convince me about stats. For me what matters is the scoreline, if we get hammered and still win then I'm a happy chap, if we hammer a side and fail to win I'm disappointed.

We may conceed more goals from the left than the right, but will that make any difference to the way the result is looked upon? In ten years, will people be arsed (or even know) what side of the pitch the goal came from? It's just nonesense in my opinion and always will be.

As for other sides, I couldn't give a monkeys how they get on, especially their stats.

Anyway Mick, bingo starts at 8.  :;):
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Postby account deleted by request » Sat Jan 03, 2009 1:29 am

A simple answer is if stats were no use .... why does almost every manager now have computer programs to provide those stats? Just for fun or because they can make use of them ?
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Postby Sabre » Sat Jan 03, 2009 1:33 am

bigmick wrote:Back to the brother in law, and their extensive use of computers, stats and probabilities. They played against the tournament favourites in the Olmpic semi's, and they game plans worked out for each player. They reckoned that based on probabilities from extensive monitoring, if player A is recieving serve, the pattern that will follow when the game is tight is that the setter (usually a short, for some reason quite hairy bloke at the front who flicks it up for the big guy) is going to set it for player B. They know the names of the players but feck knows, they're Brazillian so we'll call the big guy Pico for the sake of demonstration.

They have a read on Pico which says come the big point, two games all, 22-22 in the decider he likes to go cross court for the power shot or whatever it is. They put two blockers on him and force him to turn his body and try for an unfamiliar down the line thing, and he dumps it onto the net. Tennis players will do it as well, they'll know that at 2 sets each, 5-5 and deuce that such and such is going to serve it down the line. They don't guess, they know what the probability is.

In this area, football has much to learn.

In some aspects.

But Football is a more complex game than tennis or basketball with all due respect, or even Rugby, which also is more complex than tennis and basketball.

Any computer scientist will know that to make a tennis computer game you require easier algorythms than to make 11 muppets playing something similar to football. It's easier to program a XBOX tennis game than football game. It's easier to model a tennis player with stats (serve power, drive power, accuracy, etc), than a collective game with long transitions like football. Football is more complex than many sports.

Just as it's easier to make a math model for tennis, tennis will be covered better with stats, than football. No matter how much football wants to learn about stats.

I don't see the day stats are able to grasp the quality of a pass.

Some stats will be indeed very useful for football, but we cannot dream of covering the explanation of the game with stats. It's too complex. Just like Chess is more complex than Checkers.

In a nutshell: we can discuss the many stats that are useful in football. There are many. But we cannot assume we can just make ANY question of football and answer it with stats.
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Postby Sabre » Sat Jan 03, 2009 1:41 am

Examples of stats I consider useful:

Conceded goals: If along a season, not just 5 games, you receive a lot of goals, you can conclude you have defensive problems. You'll still won't know whether that's because of CB being cráp, or your midfield don't doing a good pressing, that will be told by naked eye.

Scored goals in a striker: Sorry, if stats say you scored 5 goals in 2 seasons, then you're not good enough for the club. You can't ignore that stat in a striker for instance. But you can ignore it for Mascherano. I don't expect him to


Where does a team shoot from? and how often? : I've seen footie programs that take all the shots a team makes and draws a bigger circle in the pitch depending the amount of shots from that positions. Yes, stats like that are used by the teams, to know where a opposition danger lies. They're useful.
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Postby ConnO'var » Sat Jan 03, 2009 1:44 am

Quadrophenia wrote:Only one stat matters. The scoreline, that's the only stat that will be taken into account in years to come.

Will people in ten years be arsed that Arsenal twatted us in the 01 cup final? No because the scoreline says 2-1 to Liverpool. Will people in ten years know Liverpool :censored: hammered Stoke this year? No because the scoreline says 0-0. That's what goes into the history books, not the meaningless stats about possesion, shots on/off target, successful passes. :censored: waste of time.

You're missing the point just a little, Bill.

Its true that the stats you pointed out do little more than to quantify performance and in a result oriented sport like football, the final score is really all that matters.

But statistics, used in a more thorough and articulate way can be used for SO much more than that. Studying past statistics provides a predictive tool for what will work in the future and THAT is not something to sniff at. It can also predict the likelihood of an individual's performance against a particular type of opponent based on a host of parameters like preferred foot, likes and dislikes, time of day, light and even sexual orientation for all I know...  :D

It is called sabermetrics specifically used for baseball performance analysis. It is however, based on extremely complex statistical analysis tools developed and used by theoretical mathematicians.

The use of these tools to quantify normal performances to the footballing audience by the media and various pundits is impossible as even most math pHD candidates have problems understanding the concepts let alone the normal Joe like you and me. It is extremely perplexing mate..... I had a look at it once and it left my head in a state of stupor. Simply could not come even close to understanding it.

Put simply, that particular methodology, while accurate, would not be of use to the normal guy and would bore the audience out of their minds if the media tried it.

These days, most football statistics used are inherently flawed to some extent as we don't use enough variables. The ACTIM index for example, is very misleading and I tend to agree with Leon that it is quite simply an oversimplified bunch of boll0cks.

However, like it or not, most of us use some sort of simple statistical analysis subconsciously whether we like it or not. Take for example the immortal thread of rotation.... Whichever camp you're in really doesn't matter.... what is important in this discussion is why we think what we do.... A lot of that is based on empirical evidence... what we've seen and hence know will work... For those of us who've never seen it work tend to be very wary of it and vise versa for those of us who have. Subconsciously, we used statistics to help us make up our mind and in this particular instance, the stat used is a very simple one.

I agree, more complex statistical analysis is required to be of use to derive high probability conclusions..... but not all simple stats are useless... we use it all the time and used correctly, they may not be able to give an accurate probabilistic prediction or explanation but they do give an idea of what's what. That's why I'm loathe to dismiss their use offhand.
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Postby Sabre » Sat Jan 03, 2009 1:51 am

That's a good post Conn, and I'm sorry I did dismiss your stats in another thread forgetting a bit the time it required to gather them, but now you can see why, I always appreciate more the opinion of a football fan to talk about a partnership than the results and numbers with that partnership.

I do agree your conclussion though, and everyone else's conclussion, stats are useful, and sometimes even the simple ones can be useful. I'm just skeptical of trying to get too much conclussions from them, and I advocate to analyse them with care.
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Postby Quadrophenia » Sat Jan 03, 2009 1:55 am

Con that's all good and well mate but still holds nothing for me. I keep using the simplicity of a result. If we lose (god forbid) but at the post match interviews and the comments on forums such as this start saying "well we won more corners" or "we had more possesion" or "we only lost by the one goal" the stat arguement loses it's credibility. That's what happened towards Houllier (who I'm very fond of as people should know by now) by the end of his Liverpool reign because he started banging on about these pointless stats, as pointed out by Carra in his book.

A result is what matters at the end of day and what goes in the history book. "We're in a results business" seems to be most common phrase in modern football and there's never been a truer word. Results are what count, not how many successful passes we make, not how many corners we had, not how many goals come from the left or right but simply the end result. I respect those who believe stats have a part in our game, but none of them make me any difference to me. It's the results that matter, top and bottom.
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