It's exactly what they do essex

So therefore a shot from 25 yards out, from a tight angle and under pressure, with every opposition player behind the ball in a tight organised unit is likely to gain a very low xG score (aka if it goes in, it's either a worldy, deflected wildly, or a keeping howler). A shot in a one on one position in the middle of the box with the goalkeeper on his line from a perfectly weighted through ball is likely to gain a high score.

It's still far from a perfect statistic, because the data compiled doesn't take into account certain variables. For example, headed chances from deep crosses tend to be rated as low percentage chances in general. But what if you have an aerial goal specialist centre forward in your team and you tend to play with that tactic and have mastered it? Your team will probably be penalised for that and it won't be reflected in your xG score. Not to mention there are some terrible players with bad finishing abilities who weigh down the score of easier chances. You can also gain a high xG score from spamming low percentage chances, which is what Liverpool have been famous for doing in past seasons vs teams with parked buses, who they've been clueless as to how they should break down (Klopp not adapting the counter press when there's a lack of space in behind, mainly).

It's still far superior to fairly meaningless stats such as total shots, shots on target, total possession and pass completion though. It's very interesting to look at when you understand it, but those stats should also be taken with a pinch a salt.

Posted By: Common Sense Police, Mar 18, 14:31:56