What is xG? | By The Numbers

xG, or Expected Goals, is the current metric of choice for the football stats community and has gained some wider traction with its appearance on the BBC’s Match of the Day, as well as plenty of comment from pundits and analysts who feel it’s either ruined or solved football. Here we explain what it all means.

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Produced by Tifo Studios: Taking an illustrated look into the beautiful game.

[shaqtaku]

Back when Lukaku was considered an elite striker

[chellakumar]

One of very few football channels out there, which could seriously improve your football knowledge. Great video Tifo Football.

[puggiu]

Always coming up with interesting stuff. Keep them coming as always

[PaddyMcMe]

I just love you guys. I'm sending this video and your channel to my 12 year old niece and 14 year old nephew who both play for the NewCastle Jets Junior Teams (Australia), your videos are succinct and comprehensive, I reckon they'll make a big difference to young kids learning the more technical aspects of the sport.

[kevinmisigaro]

Very nice topic. One of the most discussed stuff by soccer analysts. Nice to see you explaining it

[노준범-vj]

Your channel deserve more subs with this quality of video

[adamsusman]

Cool vid like always, this is a stat that's thrown around a ton. Most (including me) don't really get it. Thanks for clearing it up.

[arunravi]

There is an error - xG is the probability of the goal, and not the likelihood of the goal. It's the likelihood of the shot.

P(Goal | Shot) = L(Shot | Goal)

[FerretT]

Its definitely interesting. I can imagine clubs already plot xG in a normal distribution plot when looking at players. Harry Kane to the very right of the bell curve in the premier league - for example.

I recently plotted possession vs. xG against non top 6 teams for Liverpool as from the eye it looks they struggle breaking down buses. The plot confirmed the theory nicely.

[QT]

I really wish it had been named CQ (chance quality) rather than XG. I've talked to several (usually older fans) who dislike XG and a large part of it seems to be the name "expected goals". Many are sadly unable to get past the implication that goals are in anyway expected.

[the_joa]

After Romelo Lukaku's poor performance in the world cup, I'm sure he's now an amateur striker.😭

[manta]

Your model is useless, if it cannot predict anything or contribute to that. Any model, any statistic, any figure.
xG is an offensive metric. So a corresponding defensive one would be needed on top of that.

[Charlie_Alpha_Lima]

Thank you for this explanation! I've always known what it meant. What I didn't get was the actual number used. You've cleared that up.

[ibrahimkalmati]

So if I understand correctly then higher xg mean you have good midfield and playmaker and if you score more goals then your xg it mean you strikers did great job

[siddhantsingh]

Can anyone please help me understand how is xG(probability) greater than 1 for the Liverpool vs Swansea example ?

( how can the probability of any event be greater 100% ?)

[oliverlinehan]

As a person who works with stats and data on a regular basis I think the backlash against XG is a result of most people having no idea how stats work. Just because the data says something about one specific event (for example a football match) doesn't mean that that event "deserved to" or "should have" gone a certain way.

For example, after the 2016 US Presidential Election, a lot of people concluded that Nate Silver's "fivethirtyeight" model was wrong, since it said Hillary Clinton had a sixty-something percent chance of winning, while, of course, Donald Trump won the election. Silver's model wasn't wrong. In fact he said Trump had a thirty-something percent chance of winning the election.

Your video is spot on. XG is a model, not an exact measurement. Therefore, it is more useful for long term predictions than making conclusions about one game. It says a lot more about the repeatability of a result. We can debate all day over who "deserved" to win the Swansea vs Liverpool match. XG doesn't say Liverpool deserved to win. It says that if that game were played over many many times, Liverpool would likely have ended up winning most of them, and it suggests that Liverpool's approach to winning football games combined with their talent is overall much more likely to earn results in the league than Swansea's approach combined with their talent (which is clearly seen by their respective spots in the league table).

[chestersemaver]

It’s none of the things above.
It’s just another bit of effort to convince American Networks that the game just make sense for American public just like VAR (Americanized) and make pundits look like they know what they’re talking about.
Be ready for 4 quarter games, Time outs, challenges by the managers, repeated plays prior to a foul and most importantly a non-continuous game clock so that commercials can be inserted.
The big clubs, the networks and FIFA are slowly killing the simplest and the most beautiful game in the world just to sell their product to the US market (and don’t get me wrong, American public is just bystanders here)

[MusicStudioHits]

I friggin' love statistics in football and how they make you understand the game better

[HotChilliePa]

Great video. Really clear explanation.

[LaithAwadh]

Never seen XG but I could imagine Andy Carroll’s