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This xG nonsense


How are expected points worked out? What metrics are used?

I quite like how there are a lot more stats, metrics etc available nowadays but context is always needed
Optas takes around 10000 simulations of every game based on the xG values of every shot in the game to get how many goals the team would score on average in those 10000 simulations to get a result


Good read
 
In context of what's its for its good stat

For a league table, load of shite

Player A has 15.34 xG and he has 6 goals, you look at him and go right, he gets in right place, gets his shots on target, you expect him to start scoring eventually

Player B has 5.89 xG and has scored 11, you go well this wont last, and he scoring goals that are flukes per say or shots against a poor Keeper


I actually think its good for strikers and xGA is good for keepers

But theres alot stats which are just shite and there's no point us as fans know them
This sort of generalised thinking is the real problem with the use of xG. Player B may be on a streak or he could he Haaland. It’s very difficult to tell until you have enough data. So called “experts” ( mostly idiots on YouTube to be fair ), see that Sunderland are outperforming both our xG and xGA and think it’s a fluke and some sort of regression to mean will happen. I don’t think it will. The reason we outperform our xGA is because we defend very well. And we outperform our xG because our attacking players are pretty good too. (Also a lot of our attacks don’t result in a shot and hence gets 0 xG which can be very misleading…)
 
I think xG largely confirms what you see with your own eyes. Are Sunderland a great attacking team if we’re being honest using just our eyes? Nah. The xG also shows that.
This is what I find so frustrating with those who are so vocally and insistently against it, it's no different to how we all talk about football anyway.

"Ooh, he should have scored there, awful miss" = higher xG

"why did shoot from there he was never gonna score" = lower xG etc

There's some nuance on what makes it high or low xG, and sometimes a selective memory on chances through a match, but it's just putting a number on what we talk about anyway
 
This sort of generalised thinking is the real problem with the use of xG. Player B may be on a streak or he could he Haaland. It’s very difficult to tell until you have enough data. So called “experts” ( mostly idiots on YouTube to be fair ), see that Sunderland are outperforming both our xG and xGA and think it’s a fluke and some sort of regression to mean will happen. I don’t think it will. The reason we outperform our xGA is because we defend very well. And we outperform our xG because our attacking players are pretty good too. (Also a lot of our attacks don’t result in a shot and hence gets 0 xG which can be very misleading…)
See i don't think you can use xG, xA or xGA for teams, for me its a stat for an individual player

I did generalise it because thats how I view it, not that I spend my days looking at stats, for example say we're looking at a Striker, who has low xG and high goal count id, lean against signing him and go someone who is in and around their xG
 
I think xG largely confirms what you see with your own eyes. Are Sunderland a great attacking team if we’re being honest using just our eyes? Nah. The xG also shows that.
The problem on here is many have a bias / false knowledge of thinking chances we create are great, when really they are not. xG could be a good educational tool for these people but instead they say xG is rubbish. Because no one wants to think their own opinion is rubbish.
 
Okay in a friendly debate kind of way, using your eyes tell me why exactly we were the best team, in a way you would to a person who hadn't seen the game.
Our execution of lower xg chances was better meaning their keeper had to make more difficult saves to make. And minus the penalty (which globally was accepted as a poor decision) they created less chances. Although backed up by xg not just the naked eye
This sort of generalised thinking is the real problem with the use of xG. Player B may be on a streak or he could he Haaland. It’s very difficult to tell until you have enough data. So called “experts” ( mostly idiots on YouTube to be fair ), see that Sunderland are outperforming both our xG and xGA and think it’s a fluke and some sort of regression to mean will happen. I don’t think it will. The reason we outperform our xGA is because we defend very well. And we outperform our xG because our attacking players are pretty good too. (Also a lot of our attacks don’t result in a shot and hence gets 0 xG which can be very misleading…)
Add to that we are so confident and happy to defend often when we’ve got the lead we’re happy to sit back and really chose our moments. Will never reflect how you’re managing the game.

But like is stated across this thread. Only part of a picture
 
I noticed Everton won the xG match on Saturday, I gather a penalty scores highly. I was surprised that ours was still only 0.88 though. Felt like we created some good chances and worked Pickford quite a bit
Me too. Couldnt believe Everton had a higher XG, we toyed with them allmost all game :lol:
 
This is what I find so frustrating with those who are so vocally and insistently against it, it's no different to how we all talk about football anyway.

"Ooh, he should have scored there, awful miss" = higher xG

"why did shoot from there he was never gonna score" = lower xG etc

There's some nuance on what makes it high or low xG, and sometimes a selective memory on chances through a match, but it's just putting a number on what we talk about anyway
Over a season you can’t expect to over perform xG massively
 
For a single game, I like cumulative xG timelines for this. I think it conveys a bit more than a team is sitting back after scoring or whatever

Correct - game state plays a huge role in xG but isnt spoke about a lot. Team defending a 1 goal lead with 15 minutes to go concedes 70%+ of their total xGA in that time is a common story.
 
Does xG take account of the will to win, fight and defend a lead?

Does it also account for the fact we defend with a lot of bodies in the box?
 
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