The abbreviation ‘xG’ stands for expected goals and refers to how many goals a team or individual football player, are expected to score in a football match, based on statistical models. We’re going to explore what is xG in football and how it can be useful when it comes to betting on the beautiful game.
Expected goals is a predictive statistical model that is used to assess every goalscoring chance. Known more commonly by the abbreviation xG, these models can predict the likelihood of a goal being scored.
By assessing the probability of chances being converted, these models can be used to examine how many goals a team or individual player should have scored in a match. They can look at the types of opportunities that are being created and give a rating, based on past statistical data that shows the conversion rate of similar chances.
It is then possible to look at these stats in a wider context, or a narrower one. You can examine the xG of a team or player over the course of an entire season, to see how many goals they are expected to score per match. Or you can break it down to how they fare in home games and away matches. You could even go so far as to ask what is the xG of a team or average player performances against top six opponents, in comparison to the rest of the league?
As you can imagine, these statistics can be very useful when placing wagers on betting sites for all sorts of markets. We’re now going to take a deeper dive into xG meaning in football, by looking at some specific examples.
Let’s start by comparing the xG of two Premier League players in the 2022-23 season. Our example will show how one player can be considered to have underperformed, based on these statistics and how another has overperformed.
We’re going to look at Darwin Nunez xG, compared to that of Erling Haaland. In his minutes played for Liverpool in 2022-23, Nunez had an xG total of 13.82, but only scored nine Premier League goals. So he found the net on less occasions than he was expected to. In contrast, the Haaland xG shows a player that performed better than would be expected. His xG in the Premier League in 2022-23 was 29.63, but he actually scored 35 goals.
Now let’s examine the xG of two Premier League teams in 2022-23. The Arsenal xG was 76.5, but they actually scored 88 times. Defensively, the Gunners were expected to concede 45.1, yet performed slightly better in reality, letting in 43 goals.
Another team that did better defensively than their xG would suggest, were Chelsea. Their Expected Goals Against (xGA) was 55.3, but they actually only conceded 47 times. The Blues’ attacking output disappointed, meanwhile. The Chelsea xG was 54.8 goals, which was far in excess of their actual total of 38 goals.
Our exploration of what is xG in football now moves onto the subject of calculation. We’re going to explain how xG is calculated.
A chance in a football match will be given an xG rating between 0 and 1. The higher the probability that a chance will be scored, the higher the rating. So a chance that has a 99% probability of being converted, would be shown as 0.99xG. A 50% chance gets a 0.50xG rating, while a 20% chance would be 0.20xG.
These ratings can then be added up to give an overall score over the course of a match or season. So imagine Liverpool played Everton in a match. They create 13 chances on goal, which would each be given their own individual xG rating. Those ratings can be added up to created a sum of the total Liverpool xG for the match.
No examination of what is xG in football stats would be complete without looking at some of the negatives of this type of analysis, alongside the undoubted positives. These are the pros and cons as our experts see them:
Our analysis of football xG meaning so far should have demonstrated how it can be applied to betting. An obvious example are goals markets. If the teams’ respective xG are both relatively high and their xGA (expected against) are also quite big, then it’s fair to say that bets such as over 2.5 goals and both teams to score should land.
Low xG ratings can will point to betting on under 2.5 goals, or backing one of the teams to win to nil. With ratings for xG football meaning that you can see how many goals teams are likely to both score and concede, you can also make assessments on result markets like 1X2 betting, based on this type of stat. It certainly has its uses for identifying opportunities to take a punt.
When it comes to expected goals Premier League football is better served than just about any other European leagues or competitions. With this being the most popular football league in the world, there are a huge number of media outlets that cover it in great detail, which includes statistical analysis.
This means that Premier League xG ratings for the 20 football teams in the division are pretty easy to obtain. They are certainly more readily available than would be the case with more obscure competitions. With bookmakers competing against each other to provide the best value for the English top flight, having access to xG Premier League ratings is a very useful tool indeed.
If only all games panned out as expected, then league tables would look very different. There are literally thousands of shots had by outfield players each and every Premier League season, so that statistical metric lies behind this data. Shot types vary based on the type of assist with the likes of indirect or direct free-kick, corner kick and key pass among them.
Every four years the World Cup becomes the biggest show in town for football fans and bookies alike. The xG of players and teams that are involved at the tournament, can be analysed before the finals starts, with statistics available for qualifiers and friendlies.
Once the action starts properly, World Cup expected goals ratings can be attained after each match, which you can then use to evaluate further bets. It can highlight glaring issues within a team.
A perfect example is that of Germany in the 2022 World Cup. During the group stage they should have won every game according to xG. They had the biggest xG of any side in the tournament and the best xG difference. Yet due to not having a finisher that could convert the chances that they created, Germany were eliminated before the knockout phase.
Now our analysis of what is xG in football turns to the factors that can influence expected goals. Here are some of the aspects that statisticians consider when calculating an xG rating and goals metric:
With expected goals explained, you may now be wondering how to best apply it to your football betting. Follow these tips to boost your productivity.
Look out for instances when the odds are weighted in favour of a low scoring game, when xG suggests otherwise and vice versa. Expected goals can also point you towards teams or players that are underperforming on their xG and may be overdue some goals.
Expected goals is a stat that demonstrates the quality of chances that a team are creating. You can therefore see how their actual goal tally compares with this, which may suggest over-performance, or under-performance. It can also help with rating the performances of strikers.
The Wyscout football statistics platform, that is used by many professional clubs around the world, has a fixed penalty xG value of 0.76. In other words, penalties should be converted into goals about three times in four on average.
Vic Barnett and Sarah Hilditch are thought to have coined the term ‘expected goals’, in their 1993 paper which centred on home team performances of football clubs that played on artificial pitches.
Manchester City are a team that consistently outscored their xG in 2022-23. In the Premier League, their xG was 84.32, but they actually scored 94 goals. This was in large part down to Erling Haaland, who had an xG of 29.63, yet scored 35 goals. Kevin De Bruyne, meanwhile, scored 7 goals despite only being expected to get 5.81.
You shouldn’t bet purely on xG stats, as there are other factors to consider. For example, a team might have a great xG rating, but could be playing away from home and have injuries or suspensions to key attackers, making it less likely that they will score.