[Albion] xG table

[Bozza]

We'd be slightly better off, but it seems Newcastle have ridden their luck somewhat...



Source: https://www.bbc.co.uk/sport/football/50822875

 

[Blue Valkyrie]

If you take out Villa's injury time winner against us, and Burnley's late equaliser, we are spot on.

 

[Ninja Elephant]

I was having a bit of a row about xG on saturday with a Liverpool supporting friend. I argued it was an absolute load of complete rubbish - just a stat for the sake of another stat, but doesn't really give you anything of any great value. He argued that it's the most representative stat of how good a team is at creating chances. The underlying point he made was that Leicester have been incredibly lucky this season having scored so many goals from difficult/low percentage chances. I argued it means nothing - if Vardy wants to spank one in the top corner from his only chance every game, he will. Good lad.

 

[pasty]

I was having a bit of a row about xG on saturday with a Liverpool supporting friend. I argued it was an absolute load of complete rubbish - just a stat for the sake of another stat, but doesn't really give you anything of any great value. He argued that it's the most representative stat of how good a team is at creating chances. The underlying point he made was that Leicester have been incredibly lucky this season having scored so many goals from difficult/low percentage chances. I argued it means nothing - if Vardy wants to spank one in the top corner from his only chance every game, he will. Good lad.

I think any stat that gives a side an 18 point swing against another (Man City -> Liverpool, -14 to +4) must be complete and utter balderdash

 

[blue-shifted]

I think any stat that gives a side an 18 point swing against another (Man City -> Liverpool, -14 to +4) must be complete and utter balderdash

Also one which makes Southampton the 5th best football team in the country should also be approached with a degree of scepticism

 

[jimmygull]

Looking at this and their performance on Saturday, makes me think Bournemouth are in big danger of going down! Norwich/Villa/Bournemouth I reckon! With a big slide on for Newcastle too! We'll be fine!

 

[blue-shifted]

What I read into about XG tables is it tells you about a teams goalscoring prowess. So if a team (like Newcastle) is much lower in the XG table it says to me they are, in the real world, doing really well with their scoring chances. Southampton on the other hand have been terrible in front of goal in the real world

Joelinton better than Ings? hmmm

So XG may, or may not tell you than you need a new striker or two, beyond that I can't really see what information it gives to fans or data analysts. I've heard it said that it provides a reflection of who has been dominant in a game, or over the course of a season and in some way reflects the amount of luck a team has, so if you lose a game but have a higher XG, you've been somehow wronged. Not sure about that either. The game is about sticking it in the goal after all

 

[Badger]

Palace seem to have gone full circle. In previous seasons they've been a team which creates a lot of chances before Benteke spanks it in to Row Z. Now they seem to be riding their luck, especially against us.

 

[Kalimantan Gull]

Just nonsense isn't it

 

[Mackenzie]

We’re above palace, so I’d say it’s a pretty good indicator.

 

[Weststander]

The lofty Stains and Burnley positions say it all. Interesting to have more stats, but a bit silly.

 

[Blue Valkyrie]

Just nonsense isn't it

Not really.

Last year it showed we were way above where we should be at the half way point, predicting our fall off the cliff in the second half of the season.

Perhaps Newcastle will suffer a similar collapse this season

 

[Mtoto]

These are the rules - or assumptions - used by Opta to compile the table:

For the purposes of the above table a number of rules were set by Opta: If both teams have an xG of 0.5xG or less: 0-0 DrawIf the highest scoring team (in terms of xG) has more than 0.5xG and less than 1.1xG, they win if the xG difference is bigger than 0.3xGIf the highest scoring team (in terms of xG) has more than 1.1xG but less than 1.5xG, they win if xG difference is bigger than 0.4xGIf the highest scoring team (in terms of xG) has more than 1.5xG, they win if the xG difference is bigger than 0.5xG.



Tweaking these assumptions will almost certainly produce different final tables - including some that are closer to the actuality and therefore less newsworthy - but that's no reason to dismiss the underlying principle out of hand. Anyone who argues that xG is all complete hogwash is essentially claiming that all chances are created equal, and that there is no appreciable difference between a speculative shot from 30 yards and a tap-in from 3. Which seems a bit daft.

 

[blue-shifted]

Palace seem to have gone full circle. In previous seasons they've been a team which creates a lot of chances before Benteke spanks it in to Row Z. Now they seem to be riding their luck, especially against us.

Not really full circle is it though.

Benteke is still sticking it in row Z

 

[larus]

Not really full circle is it though.

Benteke is still sticking it in row Z

True. But it’s behind the right goal this season. Praise where praise is due.

 

[FatSuperman]

I find it useful, it shows you that a team (especially the strikers) are either under or over performing against the ‘average’ for the chances they have. I usually take it that the team either has very good or very poor strikers. Either that or they are riding their luck - this is when they tend to revert over time

 

[Bozza]

Not really.

Last year it showed we were way above where we should be at the half way point, predicting our fall off the cliff in the second half of the season.

Perhaps Newcastle will suffer a similar collapse this season

I also think xG, or something very similar, kept Hyypia in a job longer than most of us believe he merited. There were a few soundings from the Albion boardroom that the team had been unlucky, and I'm sure that was based on one/some of Bloom's statistical measures of choice.

 

[FatSuperman]

We'd be slightly better off, but it seems Newcastle have ridden their luck somewhat...

Snip

Source: https://www.bbc.co.uk/sport/football/50822875

Source: https://experimental361.com/2019/12/29/expected-goals-table-premier-league-28-29-dec-2019/

 

[Kalimantan Gull]

These are the rules - or assumptions - used by Opta to compile the table:

For the purposes of the above table a number of rules were set by Opta: If both teams have an xG of 0.5xG or less: 0-0 DrawIf the highest scoring team (in terms of xG) has more than 0.5xG and less than 1.1xG, they win if the xG difference is bigger than 0.3xGIf the highest scoring team (in terms of xG) has more than 1.1xG but less than 1.5xG, they win if xG difference is bigger than 0.4xGIf the highest scoring team (in terms of xG) has more than 1.5xG, they win if the xG difference is bigger than 0.5xG.



Tweaking these assumptions will almost certainly produce different final tables - including some that are closer to the actuality and therefore less newsworthy - but that's no reason to dismiss the underlying principle out of hand. Anyone who argues that xG is all complete hogwash is essentially claiming that all chances are created equal, and that there is no appreciable difference between a speculative shot from 30 yards and a tap-in from 3. Which seems a bit daft.

My issue with it is that if a speculative shot from 30 yards is saved, but then falls to the feet of an unmarked striker for a tap in, the total xG of the move is quite high, but only happens because of the speculative shot from 30 yards.

Tell me if I'm wrong, because I haven't looked into the stat in great detail, but I imagine that it is assuming that all chances are independent events and can be summed to give a total xG for the match (or player, or whatever). But goal scoring chances are not independent events, as in the example above. You can also imagine a situation where a striker misses 3 easy tap ins in the same sequence, with the keeper making brilliant point blank saves, but scores with the fourth. The xG for each chance is greater than 0.5, so the total xG for a single goal in that scenario would be >2. Has that been accounted for?

I like the idea of the stat, but I don't believe that it is accurately capturing what is happening in a game.

Are they also claiming that this stat is predictive of future performance, because I also find that hard to accept?

 

[Bozza]

I think any stat that gives a side an 18 point swing against another (Man City -> Liverpool, -14 to +4) must be complete and utter balderdash

Liverpool have squeaked their way through a fair number of games though, including against us.

Now, maybe they had other gears available to snatch further goals, if required, but they've had a fair number of relatively unconvincing victories thus far this season.

Maybe not enough for an 18-point swing though...