xG is absolutely pointless
- Thread starter Stu999
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Soldato
Yeah, I think it's nonsense personally. It's utterly meaningless. You can tell from other stats how a game is going if you aren't watching it live, and if you are, you'll be focussing on the ACTUAL score rather than some made up 'expected' score.
Soldato
The xG stat is used by those to help them cope that the result hasn't gone in their favour.
Soldato
Yeah doesn’t really mean anything. I guess it’s a bit of a guide of form but that’s about it. It seems to be trotted out more when it’s wrong rather than when it’s right.
There's nothing wrong with xg, it's just people don't understand what it is and how it should be used.
It's a simple measure of the quality of chances a side has/has faced. It doesn't tell you how well a side has played, nor who should have won, just how likely a particular chance was to result in a goal. Saying you don't like xg is like saying you don't like people saying 'that was a great chance to score'.
Football clubs use and are developing far more complex xg related stats to measure every single pass and movement on the pitch to see how likely it is to lead to a goal. It's not very controversial either, all they're doing is quantifying what scouts have traditionally done in the past to get more accuracy.
It's a simple measure of the quality of chances a side has/has faced. It doesn't tell you how well a side has played, nor who should have won, just how likely a particular chance was to result in a goal. Saying you don't like xg is like saying you don't like people saying 'that was a great chance to score'.
Football clubs use and are developing far more complex xg related stats to measure every single pass and movement on the pitch to see how likely it is to lead to a goal. It's not very controversial either, all they're doing is quantifying what scouts have traditionally done in the past to get more accuracy.
Caporegime
This is like saying "whats the point of odds for betting companies, things don't work out like they should all the time".
xG is a good metric to see how a team is creating chances and conceding chances. The fact that over the course of a season all these stats usually track a teams performance should tell you that they aren't pointless.
Its statistical analysis. I don't know how you can argue against that being useful in pretty much any sport. Plenty of sports have been absolutely revolutionised by statistical analysis. Its how plenty of football clubs have developed top tier scouting networks for finding talent.
No its not infallible but its quite literally saying that based on thousands and thousands of real world events, this is likely to happen.
You just need to understand a little about statistics to appreciate it. Just because you toss a coin and it comes up tails 4 times in a row doesn't mean that the coin is bent or that there isn't a 50% chance of heads coming up next time you flip it. It doesn't invalidate the probability.
xG is a good metric to see how a team is creating chances and conceding chances. The fact that over the course of a season all these stats usually track a teams performance should tell you that they aren't pointless.
Its statistical analysis. I don't know how you can argue against that being useful in pretty much any sport. Plenty of sports have been absolutely revolutionised by statistical analysis. Its how plenty of football clubs have developed top tier scouting networks for finding talent.
No its not infallible but its quite literally saying that based on thousands and thousands of real world events, this is likely to happen.
You just need to understand a little about statistics to appreciate it. Just because you toss a coin and it comes up tails 4 times in a row doesn't mean that the coin is bent or that there isn't a 50% chance of heads coming up next time you flip it. It doesn't invalidate the probability.
Caporegime
Like what?
No, it isn’t. There’s an obvious point to betting odds. A trade off between enticing punters to gamble and losing money, that’s the entire “game”.
Your last point is what I was really getting at. A lot of fans don’t understand much about it so say things after a loss like, “Well, the xG was x for us and y for you, so we should have won”.
The moneyball stuff and statistical analysis is great, I’m unsure what value is derived from putting it out to fans.
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Possession, shots, shots on target, corners conceded, bookings, etc., etc. Hard to believe you couldn’t have guessed this.
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Associate
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- 2 Feb 2009
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I find xg is much better at telling you how the game actually went, than any of the above, with the possible exception of "Shots on Target" but even then.
two teams could have the same shots on target, one team both shots from 25 yards.. (xG 0.1) and trickled to the keeper, the other from inside the 6 yard box, (xG 1.4) which caused great saves..
I would definately say the second team had the better of the game..
I personally like xG.. as long as you take it for what it is..
Soldato
What the sport and enjoy it for what it is. Stats are for the nerds. 
Associate
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Ah yes .. what kind of forum are we on at the moment??? an overclocking computer bits shop forum.. does it get more nerdy?!?What the sport and enjoy it for what it is. Stats are for the nerds.
So yes totally agree
Caporegime
And where do you think those odds come from? They aren't just thinking about what will entice punters. They are looking at the likelihood of each item happening. Again, almost certainly through analysis of huge datasets...just like xG. Defensive records, xG, injuries, form etc will all go into these things.
To be somewhat obtuse, that isn't incorrect. Football is a game of goals. If you play the other team off the park and lose 3-0 then you still lost. Saying you should have won is irrelevant. Playing the other team off the park and losing 3-0 with an xG of 3-1 in their favour says that you didn't create enough chances ergo you didn't play well in the areas that matter.
If the idea of football is to create and score chances then a metric that quite literally tracks the quality of the chances you create should tell you who wins a game more often than not... and it does. I don't know how you can argue against a metric that looks at massive amounts of historic data and derives its predictions based on that. What it is saying will happen, has happened.
This is the bit that I don't think people are getting. Its not guess work, its data. If tomorrow people starting scoring penalties at 50% instead of around 80% then the stats would soon reflect that. The stats reflect all teams as well, they aren't just looking at the very elite players, they are looking at all of them. This is how predictive modelling works. You can't say for certain something will happen but you can say what the likelihood of it happening is.
What overall xG isn't good at explaining is how it came to that figure. Was it 3 amazing chances or 15 minor ones etc.
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Caporegime
Chelsea had no bookings last night, they must have absolutely dominated us then.
Caporegime
Right, thats it, i'm buying everyone this for Christmas!
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Soldato
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- 3,573
Theres been loads of games and will continue to be where a team has a 2 xg difference but the game just didn’t play out like that. At all!
Doesn’t factor in refs decisions either, take PSG v Newcastle the other day. Ref isn’t a complete balloon head Newcastle win it. PSG where awful infront of goal and could have played for another 90 minutes. xG doesn’t tell you that at all.
Soldato
Like most stats in a football match, it’s never wise to rely solely on one stat alone to tell you how a game went. You need a much wider range to form an accurate opinion. Hence why I said further up, though jokingly, that’s it better to leave the stats to the nerds.
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