League Two - xG Data

Quoted from OddShapedBalls

Do you write your team name on the back of a cigarette packet too?  - I'm only joking btw

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Quoted from OddShapedBalls

Who was the first chap to really analyse football games?  Can't remember off the top of my head but anyway he discovered that the vast majority of goals were scored in 3 passes or less from his data, and everyone immediately decided that this meant long ball was the best way to score goals without thinking about the fact a high press to turnover ball near the opposition box would also result in a '3 passes or less' goal etc.   The data is only as good as the person reading it really

John Beck?

Quoted from OddShapedBalls

Who was the first chap to really analyse football games?  Can't remember off the top of my head but anyway he discovered that the vast majority of goals were scored in 3 passes or less from his data, and everyone immediately decided that this meant long ball was the best way to score goals without thinking about the fact a high press to turnover ball near the opposition box would also result in a '3 passes or less' goal etc.   The data is only as good as the person reading it really

Like him or loathe him I believe the late Don Revie was one of the first to keep an analysis of players. Whether he included data on the actual games or not I don't know.

Quoted from OddShapedBalls

Who was the first chap to really analyse football games?  Can't remember off the top of my head but anyway he discovered that the vast majority of goals were scored in 3 passes or less from his data, and everyone immediately decided that this meant long ball was the best way to score goals without thinking about the fact a high press to turnover ball near the opposition box would also result in a '3 passes or less' goal etc.   The data is only as good as the person reading it really

Howard Wilkinson maybe?

You can often reach the wrong conclusions when reading data, and what might be a solution for one team, would not work for another with the same data.

My general issue with xG is two fold:

a) I feel it's very on-trend, and far too many kids are crying over it as if it's more worthy than the goals column

b) who questions the validity of how it's calculated? For example, looking at the data provided during that Salford game, it looks like Khan's chance (which he scored) was about 0.4, so 40% of the time from that position, in those exact circumstances, he'll score, 60% of the time he'd be expected to miss.

But then you look at Salford's fourth. It jumps by about 0.3, yet the bloke heads it in, relatively unchallenged, three yards out. Is the data suggesting he'd only likely convert that chance 30% of the time? Because most footballers will bury a header from that range. I'd personally put it at 0.8 or 0.9.

So who is making these decisions? Obviously someone is watching; something (programmatic or robotic) is measuring. I'd question the quality of that programming.

We might still be forming opinions on an unreliable methodology. People have bought into it, almost without question or scrutiny.

It's trying to make something subjective, objective. It's not as black and white as 'did the ball cross the line' or 'was he offside'? Attaching value to a unique set of circumstances is incredibly difficult to put a number to, so there's masses of mistrust from me, and mistrust towards people who put too much faith/value in it (for now).

Maybe I need educating more, but I think it's healthy to question the validity of most things.

All teams do data analysis now, suggesting there is little to be gained by doing so, because everyone else is.

But if you don't do it, then you would be at a disadvantage compared to others, so it's become a big part of the game.

I think that is why some fans are baffled by team selections and the use of substitutes during games. The management have training data and up to the minute match data that we are not privy to.

For instance, injuries are more likely to occur when a players recovery rate has dropped below a certain parameter and can be the reason he's replaced, even though he appears to be having a good game.

We often hear fans say how someone is blowing out of his ar$e and they couldn't understand why he was kept on, but the data is probably telling a different story.

Quoted from OddShapedBalls

Who was the first chap to really analyse football games?  Can't remember off the top of my head but anyway he discovered that the vast majority of goals were scored in 3 passes or less from his data, and everyone immediately decided that this meant long ball was the best way to score goals without thinking about the fact a high press to turnover ball near the opposition box would also result in a '3 passes or less' goal etc.   The data is only as good as the person reading it really

Charles Hughes

Quoted from Les Brechin

Not into all this xG crap.

The only statistic that matters is how many times you put the ball into the net!

And how many the ball ends up In yours !

Data can be selective and used to support any point of view needed.

  I saw a stat this week that Leeds had faced 55 good chances against them this season.  The most in the PL. The number includes goals against and chances that should have conceded a goal.

Despite this Leeds are not in the bottom 3 and will probably stay up.  

Quoted from RichMariner

My general issue with xG is two fold:

a) I feel it's very on-trend, and far too many kids are crying over it as if it's more worthy than the goals column

b) who questions the validity of how it's calculated? For example, looking at the data provided during that Salford game, it looks like Khan's chance (which he scored) was about 0.4, so 40% of the time from that position, in those exact circumstances, he'll score, 60% of the time he'd be expected to miss.

But then you look at Salford's fourth. It jumps by about 0.3, yet the bloke heads it in, relatively unchallenged, three yards out. Is the data suggesting he'd only likely convert that chance 30% of the time? Because most footballers will bury a header from that range. I'd personally put it at 0.8 or 0.9.

So who is making these decisions? Obviously someone is watching; something (programmatic or robotic) is measuring. I'd question the quality of that programming.

We might still be forming opinions on an unreliable methodology. People have bought into it, almost without question or scrutiny.

It's trying to make something subjective, objective. It's not as black and white as 'did the ball cross the line' or 'was he offside'? Attaching value to a unique set of circumstances is incredibly difficult to put a number to, so there's masses of mistrust from me, and mistrust towards people who put too much faith/value in it (for now).

Maybe I need educating more, but I think it's healthy to question the validity of most things.

It's very complex, Smiths header for Salford may be lower because you would also expect a defender or the keeper to collect the ball.

Playing devils advocate here as I've seen people saying our xG highlights our need for a striker to convert them. What if our xG is actually coming from midfielders and defenders at set pieces?