In this football language post we look at a phrase that is becoming more popular in football as we find ways to describe shots on goal – expected goals or xG. If you have questions or comments about this or any other phrase then email us at: firstname.lastname@example.org.
Expected Goals (xG)
The phrase xG stands for expected goals and is another way of describing shots on goal and whether these shots would have had a high probability of being scored or not. Sometimes a shot on goal, or on target, may trouble the keeper who has to make a great save to keep out the ball. Other times the striker may have miskicked the ball or not hit it with any power meaning that the keeper can make an easy save – both of these are counted as shots on goal but clearly the first of these was a more dangerous, or clear cut, chance, that is, it had more chance or probability of going in than the second example. Therefore, the expected goal or xG metric (a way of measuring things) helps to decide the level of the chance.
The number system in place to measure the xG is simple: the closer the number is to 1 the better the chance. So, for example, we could ‘measure’ a half-chance, this is not such an easy chance to score from, as 0.5 xG. If the number is 0.9 then we would expect the chance to be converted, or scored, 90% of the time – you don’t want to miss those ones! If a chance is viewed as having an xG of 0.2 then this is a much more difficult chance – only top strikers will probably be able to finish it. We can also use it to see whether a player should have scored or not – we can see who are the top finishers (the clinical finishers) and who are wasteful in front of goal.
What criteria is used?
How far away from goal, whether it was a shot or a header, a one-on-one situation when a player is through on goal, the nature of the assist, whether it was from open play or from a set piece and the position of the player shooting are some of the factors taken into consideration when deciding on the xG. Of course, it is not perfect, for example, it doesn’t take into account who has hit the shot – a Harry Kane shot may rank higher than a Harry Winks one for example – but it might be seen now as a measure of how well (or not) a team has played. Expected goals (xG)