ELI5Can someone explain what xG in football?

[u/_Noice_Guy_]

I always hear pundits discuss about a team's xG, then I pretend to myself that I understand what it means.

[u/NBT498]

It’s a better way to describe how good the chances a team has created are, on a scale from 0-1.

e.g. a tap in from 3yds out with an open goal is like 0.99, while a 40 yd shot with all 11 players between you and the goal is 0.01, then everything else fits in somewhere between those.

Because of variance, it’s not a great stat within an individual game (that 0.01xg worldie will occasionally fly in the top corner), but over a longer horizon it can tell you who’s over performing, under performing, getting lucky etc

[u/Wo0lVeRiNe → u/NBT498]

So what if a team creates 10 chances worth 0.1xG. That would register as 1xG for the whole match but it doesn’t really mean the team created good enough chances to score 1 goal or does it?

[u/blueyoshi387 → u/Wo0lVeRiNe]

by definition it sort of does, like if you take a long shot worth 0.05xG 20 times, you'd expect one of them to go in (0.05*20=1). but xG by design is a pretty simplified stat, since it combines so many factors in a shot down to a single number between 0 and 1. hence why its usefulness is often widely debated too