‘XG’

[Ainsley Harriott]

I listen to the ‘BladesPod’ podcast thing. That Blades Analytical knows his stats. I love a stat.

But...

What is ‘XG’ or ‘expected goals’? How is that calculated? What does it even mean? Think he’s just said our ‘xg’ at West Brom was 0.63.

I’m stumped.

 

[BigBed]

It's the "pies sold per fan" numerology, I wouldn't worry to much about it.

 

[grafikhaus]

What are “expected goals” (xG)?

To work out a team's “expected goals” (xG) for a match, every shot must be analysed and given an "Expected goal value" (EGV).

EGV is the probability that any given shot will end up as a goal.

As Patrick Lucey, director of data science at STATS, explains, EGV is based on a number of factors, such as where the shot was taken from, the proximity of defenders, the nature of the attack (i.e a direct free-kick or a penalty). The EGV of a shot assumes it is being taken by someone of average ability in the league, so it expects for instance that a shot from 10 yards out plum in front of goal with no defenders nearby has a high chance of ending up as a goal.

From an analysis of every shot's EGV in a match, an "expected goals" (xG) figure can be placed on each team from that match. If a team has a higher xG figure than actual goals scored, it will broadly be because of wasteful finishing or good goalkeeping, or both. Likewise if a team is scoring more than its xG then it could be down to moments of individual brilliance from an attacker or say a goalkeeping error. Link.

Me neither. I think it's all a load of bollocks designed to over-complicate a simple game and make the studio pundits look like they know what they're on about. They should stick to 'I've seen them given.'

 

[FleaPitBlade]

Every ''chance" is given a rating of its goal likelihood based on how many times it will be scored. A tap in on the line might be scored 99/100 times so would have an xG of 0.99 where a pot shot from 30 yards might get an xG of 0.05. They calculated from a database of thousands of similar chances.

These are added up to give an xG rating for a whole game and are used as a metric that paints a picture of how each team performed that looks deeper than the scoreline.

 

[Kozzy_is_my_Dad]

I like a stat too.

I'm not sure this one is needed?

 

[Ainsley Harriott]

I like a stat too.

I'm not sure this one is needed?

No, it isn’t. It’s absolute rubbish.

 

[Ainsley Harriott]

What are “expected goals” (xG)?

To work out a team's “expected goals” (xG) for a match, every shot must be analysed and given an "Expected goal value" (EGV).

EGV is the probability that any given shot will end up as a goal.

As Patrick Lucey, director of data science at STATS, explains, EGV is based on a number of factors, such as where the shot was taken from, the proximity of defenders, the nature of the attack (i.e a direct free-kick or a penalty). The EGV of a shot assumes it is being taken by someone of average ability in the league, so it expects for instance that a shot from 10 yards out plum in front of goal with no defenders nearby has a high chance of ending up as a goal.

From an analysis of every shot's EGV in a match, an "expected goals" (xG) figure can be placed on each team from that match. If a team has a higher xG figure than actual goals scored, it will broadly be because of wasteful finishing or good goalkeeping, or both. Likewise if a team is scoring more than its xG then it could be down to moments of individual brilliance from an attacker or say a goalkeeping error. Link.

Me neither. I think it's all a load of bollocks designed to over-complicate a simple game and make the studio pundits look like they know what they're on about. They should stick to 'I've seen them given.'

Thanks for your reply.

But what absolute bollocks that is. Think it’s the reply below yours gives the tap-in shot as a 0.99 XG. Fair enough. But say that’s Connor Sammon tapping it in. Is it then 0.09? Load of shit

 

[FleaPitBlade]

Well, it's useful if your glancing at results and want to know of a scoreline was justified, lucky, against the run of play etc.

Or if a teams run of results or performances is sustainable either in success or failure.

Teams and players will invariably level out to their xG over the longer term (for and against) because it's calculated using the averages.

If you've peppered a team for 90 minutes and got caught on the break, the xG will be in your favour and over time will be a better indication of how your form may pan out than that result in isolation.

 

[grafikhaus]

Thanks for your reply.

But what absolute bollocks that is. Think it’s the reply below yours gives the tap-in shot as a 0.99 XG. Fair enough. But say that’s Connor Sammon tapping it in. Is it then 0.09? Load of shit

Same as 'shots on target'. So a 20-yard 'bobbler' which a goalie could throw their cap on counts as much as a 30-yard screamer into the top corner? Ditto 'possession'.

I'm a fan of stats (you may have noticed...) but only if they're relevant.

Like this one:

 

[Rodley]

I like a stat too.

I'm not sure this one is needed?

I think it’s really useful.

If a team has an XG of 3 goals a game and the opposition has an XG of 1 goal a game, it indicates that they ought to be winning that match. You’ll find some teams start the season with stats like that and may spend the first 3 games in the relegation zone, but ultimately they’ll turn it around as they will start converting those really good quality / easy chances. So it’s useful to see if a team is performing worse than they should be, or vice versa.

I also think it’s useful in analysing individual players. Wendy were flying at the start of the season with Adam Reach scoring lots. However his XG was much, much lower each game. So he was scoring lots of chances which typically had very little chance of going in (i.e worldies from 40 yards). His form eventually dropped to the average data of the league.

Some players do exceed their XG and these are the top, top players in the division. So do some teams. But I think it’s a useful stat to see who is underperforming and who is overperforming.

 

[Carlton Blade]

It's just a stat that tells you how good the chances you created were. Also tells you if you are clinical when you link it to how many goals you score. xG against shows the same for you defensively.

If you are outscoring your xG significantly, chances are you're scoring wonder goals. Perfect example was Harry Wilson. Scored 5 or 6 goals from miles out which had low xG. At a glance and without further knowledge you could think that's sustainable. But his xG was so low that, by averages it was going to drop off.

Stats are amazing tools when used in conjunction with watching the games. To dismiss something that all clubs use to illustrate performance quality as useless is harsh

 

[tomtheblade]

Thanks for your reply.

But what absolute bollocks that is. Think it’s the reply below yours gives the tap-in shot as a 0.99 XG. Fair enough. But say that’s Connor Sammon tapping it in. Is it then 0.09? Load of shit

The whole point is that it doesn't specify the player involved. Therefore it's not 'a load of shit' as it can convey useful information about the chances a team is creating and how effective they are at converting them.

Eg. A team has a very high xg score but is not scoring many? Well then chances are you have a connor sammon up front and need to buy a striker pronto.

It quantifies something that people often judge after a match - 'we created plenty of chances but couldn't put them away'. It tells you a lot about how your team is doing offensively, and if you need better midfielders (low xg but plenty of goals), or better strikers (high xg but low goals).

 

[Flatulent_Bob]

It demonstrates the quality of chances created and likelihood of scoring.
It’s a much better indicator or how the team is playing and the balance of the match compared to possession or shots on/off target.

 

[Revolution]

Teams and players will invariably level out to their xG over the longer term (for and against) because it's calculated using the averages.

Not necessarily. A good striker may well consistently exceed his xG every year. That's an indication of value.

 

[Berkshire Blade]

Its a better version of the 'shots on target' stat.

 

[stringer]

Same as 'shots on target'. So a 20-yard 'bobbler' which a goalie could throw their cap on counts as much as a 30-yard screamer into the top corner? Ditto 'possession'.

I'm a fan of stats (you may have noticed...) but only if they're relevant.

Like this one:

View attachment 50289

xG is more scientific and meaningful than shots on target because, as you say, one from 40 yards that rolls into the arms is counted the same as a tap in on the line. xG takes these factors into account. I don’t mind it, I wouldn’t obsessively use them but it’s a decent indication of whether you’re doing the right things or not, ie creating good chances for your strikers

 

[ChemEngBlade]

What are “expected goals” (xG)?

To work out a team's “expected goals” (xG) for a match, every shot must be analysed and given an "Expected goal value" (EGV).

EGV is the probability that any given shot will end up as a goal.

As Patrick Lucey, director of data science at STATS, explains, EGV is based on a number of factors, such as where the shot was taken from, the proximity of defenders, the nature of the attack (i.e a direct free-kick or a penalty). The EGV of a shot assumes it is being taken by someone of average ability in the league, so it expects for instance that a shot from 10 yards out plum in front of goal with no defenders nearby has a high chance of ending up as a goal.

From an analysis of every shot's EGV in a match, an "expected goals" (xG) figure can be placed on each team from that match. If a team has a higher xG figure than actual goals scored, it will broadly be because of wasteful finishing or good goalkeeping, or both. Likewise if a team is scoring more than its xG then it could be down to moments of individual brilliance from an attacker or say a goalkeeping error. Link.

Me neither. I think it's all a load of bollocks designed to over-complicate a simple game and make the studio pundits look like they know what they're on about. They should stick to 'I've seen them given.'

Sounds like a majestic way to waste time instead of tackling real issues within the game

 

[Hunter_999]

We have the best XGDifference in the league. We play the best football and *should* score more goals than the opposition. We also do as we have the best goal difference.

 

[HodgysBrokenThumb]

The whole point is that it doesn't specify the player involved. Therefore it's not 'a load of shit' as it can convey useful information about the chances a team is creating and how effective they are at converting them.

Eg. A team has a very high xg score but is not scoring many? Well then chances are you have a connor sammon up front and need to buy a striker pronto.

It quantifies something that people often judge after a match - 'we created plenty of chances but couldn't put them away'. It tells you a lot about how your team is doing offensively, and if you need better midfielders (low xg but plenty of goals), or better strikers (high xg but low goals).

If you have Connor Sammon up front and the manager needs stats to tell him you need a new striker, then you need a new manager...

 

[SwissBlade]

It allows the stattos to really focus in on where a team is performing or not.

Interestingly the stats earlier in the season, when results and league positions were quite volatile, it allowed our Bladespod friends to really analyse our performances.

I don’t fully understand it, but I know that our stattos do and they’re able to explain what it means in layman’s terms for simpletons like me.

Ainsley Harriott dont worry about the xg but just know that when Andy hinchcliffe on sky, Kevin Gage and Bladespod are referring to it, that they are supporting their point with these stats at hand. Rather than some bbc, bt sports or some of the sky commentators just commenting on stuff they like or dislike.

 

[HodgysBrokenThumb]

Spurs had 1 shot on target last night - by a defender who put into his own goal. The stats suggest Trippier should replace Kane up front.

 

[Aston max]

How about this one
WTF

 

[SwissBlade]

How about this one
WTF

That’s generally used by wednesday fans as they’re bouncing, having come from 0-2 down against a shitty little neighbour to equalise and then to see some little ginger lad pop up and smash one home

Often followed by

FFS

Neither are really statistic based, but can be used in conjunction with stats to take the piss

 

[georgebernardshaw]

Fuck me, is this what the beautiful game has been reduced to?

 

[bibbity bobbity boo]

I listen to the ‘BladesPod’ podcast thing. That Blades Analytical knows his stats. I love a stat.

But...

What is ‘XG’ or ‘expected goals’? How is that calculated? What does it even mean? Think he’s just said our ‘xg’ at West Brom was 0.63.

I’m stumped.

Glad you asked, I didn't have a clue either.

 

[Maidenhead]

When they start awarding points for XG, then I'll start to worry about it.

Until then I'll watch the games and trust my own judgement as to which was the better team, who scored the most goals, and where the points are going just as I have done for the last 60+ yrs

 

[Northyorksblade]

I think it's really interesting. Is there an up to date list based on it for the championship? Interested in our xg v the teams we have yet to play.

 

[Corazon]

Do all companies and individuals share the same database to calculate XG? Or does everybody compile their own?

 

[Aston max]

That’s generally used by wednesday fans as they’re bouncing, having come from 0-2 down against a shitty little neighbour to equalise and then to see some little ginger lad pop up and smash one home

Often followed by

FFS

Neither are really statistic based, but can be used in conjunction with stats to take the piss

Have a like young man

 

[snb69]

Like it or not, the use of stats like this, as well as things like heat maps is part of the future of football coaching at the top level. It doesn't replace the basics, but it can add value if used intelligently