Table of Contents
- What is xG in soccer?
- Why is xG in soccer important?
- How is xG calculated?
- Is xG accurate?
- What are the pros & cons of xG in soccer?
- An example of xG in soccer
- Recap: Understanding xG in soccer
A term only coined within the last decade has become part of soccer parlance wherever we read game statistics.
xG has changed the way many people interpret soccer matches, but what is it? And how does it work?
In this article, we’ll look at the details behind xG, whether it’s an important statistic, and if it’s here to stay.
What is xG in soccer?
In soccer, xG stands for ‘expected goals’, indicating the number of goals a team should’ve scored from the quality of chances presented to them in a game.
It’s important to remember that there are different xG models that organizations use, which is why you might see different xG scores for the same game on different websites.
When displayed, the xG will often be in brackets next to the actual amount of goals a team has scored, possibly with an asterisk which advises the reader that the bracketed score is, in fact, xG.
The calculated xG isn’t necessarily a whole number, meaning a team can achieve an xG score of up to two decimal points
How goals and xG are displayed together might look like this example: Real Madrid 3 (2.46*) – 0 (1.03*) Valencia.
The disparities between actual goals and the xG score exist for several reasons, but reasons include a team being wasteful in front of goal or a goalkeeper having a stellar performance.
Why is xG in soccer important?
xG highlights the quality of chances that are afforded to a team within a game, enlightening those that perhaps didn’t watch the whole game to another metric so they can get a more balanced reading of what occurred.
If the statistics read that Team A had 17 total shots in a game compared to only 3 by Team B, it’s reasonable to assume that Team A was dominant during this game. However, this could be misleading because 15 of those shots from Team A could’ve been from 30 yards and sailed well wide of the goal.
Conversely, maybe the 3 chances Team B had were much easier chances to convert, possibly all ‘tap-ins’ in the 6-yard box.
Most viewers will be able to gauge from watching the game who created better chances and might arguably deserve to win the game, but if you’re just seeing the scoreline at home with some basic statistical information provided, you might want more context to what happened.
And that’s what xG offers: context. There are those in the sport, however, who feel that xG is either irrelevant, unimportant, or just a fad that will go out of style.
Depending on your viewpoint, you might nod and agree with those who ignore xG. At the end of the day, fans, coaches, players, and just about everybody else in the game want to win. There’s merit to the argument that some don’t care about this statistic if their side scores more actual goals than their opponent.
How is xG calculated?
Numerous factors come into consideration in terms of your xG score, like which part of your body the shot was attempted with, the angle and how far out you’re shooting from, and the perceived quality of the pass played into the striker, among other things.
The quality of any goal scoring chance within soccer will be given an xG rating of value between 0.00 and 1.00. If a shot is given an xG rating of 0.20, it basically means that there is a 20% likelihood that it will be scored.Interestingly, Opta, the most trusted source of statistics in the Premier League, fixes penalties to an xG of 0.79 because they are scored 79% of the time.
Is xG accurate?
A lot of the different systems that measure xG use the same collection of data, but might read them slightly differently.
Generally speaking, most xG scoring systems generate a similar xG to that of fellow systems.
In terms of xG being an accurate way of measuring how a team plays, it’s not always easy to say. For instance, a team could be gifted a goalscoring chance worth 0.99 through a sloppy defensive mistake, not because of intricate passing moves.
Therefore, it indicates that the opposition has done poorly in this case rather than your side doing well.
But this is the beauty of soccer: you can’t tell the whole story from statistics alone. Statistics offer more context, yes, before to get a complete grasp on what’s happening, you need to watch it yourself.
What are the pros & cons of xG in soccer?
xG is another form of data that can help coaches with their tactical tweaks and training regimes.
Head coaches can take a crumb of comfort from the fact that, if their xG is high, they’re creating the chances so the side shouldn’t be too concerned if they’re not scoring yet, they just need to work on their finishing. Traditionalists will suggest that managers should be able to see that without xG, however.
xG also encourages more people in the game to think analytically, increasingly becoming more insightful about the game.
What a lot of xG calculators don’t account for is the person who is taking the shot. If Erling Haaland, arguably the world’s best striker, is one on one with the goalkeeper, it’s reasonable to assume that he’s more likely to score the chance than Nathan Ake, respectfully, because Haaland is a striker and Ake is a defender. Yet, the chance presented to them is theoretically the same, according to a lot of xG metrics.
Another drawback might be that, because the xG varies depending on which pool of data is measuring the game’s statistics, it’s not entirely trustworthy. If one data analyst measures it differently to another, you might not know which one to believe, even if the figures are close.
An example of xG in soccer
Here’s some fun trivia about a game that couldn’t possibly have been fun: the lowest xG ever recorded in a single game. As far as a lot of experts can find at the professional level, we head to the Spanish south coast where Granada hosted Atlético Madrid to play out a (yes, you guessed it) goalless draw. Staggeringly, the xG score was 0.08 v 0.07.
Under then-manager Graham Potter, Brighton & Hove Albion were the subject of online ridicule for some time as they always posted high xG scores, meaning they created good chances, but had a very low return in the actual amount of goals they scored.
For example, in the 2020/21 season, Brighton averaged an xG of 1.63 per game. However, to the frustration of the fans, only managed to muster 1.05 goals per game.If Brighton fans thought they had an xG curse, spare a thought for Italian outfit Atalanta. In a game versus Empoli in 2019, Atalanta tallied a frankly incredible 47 shots (the most shots in a game in one of Europe’s top five leagues since this statistic began to be collected) throughout the entire match, registering an xG score of 5.86 in the process. Empoli, on the other hand, only had 3 shots all game. Ludicrously, the game finished 0-0, which meant, at the time, it was the highest xG ever recorded by a team without scoring.
Recap: Understanding xG in soccer
So there you have it! A comprehensive guide to xG and its curiosities.
The next time you go to check the score of a game, remember to search out the xG of both sides too for a better understanding of how things unfolded.