Match of the Day using expected goals (xG) has really thrown the concept into the public eye but what is it?
When it appeared on the BBC programme during the first Saturday of the Premier League season, it left a lot of fans scratching their heads.
But it’s not an entirely new concept and is one way many statistical analysts use to assess a team’s attacking chances.
So with it now going mainstream, don’t worry if you are unfamiliar with what xG is, because we’ve got it covered.
Opta analysed more than 300,000 shots and a number of different variables to create the expected goals metric.
On a simplistic level, it is basically judging how likely a player is to score from a certain chance, putting a number on something a lot of people judge when watching a game.
And the latest edition in our Science in Football series should clear up any questions you have over expected goals.
Football Whispers’ James Lorenzo and Bobby Gardiner have looked at look at what exactly xG is, what goes into calculating it – including the speed of attack and the type of ball used to create the opportunity – and how you can understand the ratings?