Using Expected Goals (xG) to Improve your Football Betting
Expected Goals (xG) as a football statistic has been around for a good few years now but it’s only in the last few season that it’s really come into the mainstream. Often dismissed by people who don’t always understand exactly what it is, it struck a chord with two types of football fans in particular, the football hipster and the football bettor.
So what is Expected Goals anyway? Basically when a football takes a shot that shot is compared to the 1000s and 1000s of shots on goals from similar, or the same, position(s) and it’s given a percentage chance of a goal being scored.
It’s been shown over the last few seasons that xG data collates with goals scored. Click that link and you’ll be brought to a post that shows xG and goal stats from Premier League seasons 2016-2019. As you can see it’s a great indicator for how many goals a team will score.
Let’s use a recent example. Recently, Manchester City beat Chelsea 2-1 at the Etihad. The xG score however was 1.40 : 0.80. What does this mean? Basically, City scored two chances that under normal circumstances they wouldn’t have scored, while Chelsea scored one and were expected to do some from the stats.
Using xG to Predict Goals
Chelsea opened the scoring when a through ball found N’Golo Kante, he had a battle to get it into the net, but being a chance that was straight in front of goal and a goalkeeper that was out of position Kante’s shot had a high xG. City’s Kevin de Bruyne levelled the score with a shot that had a low xG, while de Bruyne is one of the best in the league at long shots the truth is they don’t generally go in when they’re made. Most goals are scored from between the penalty spot and the goal line. De Bruyne’s shot was deflected and went in.
A few minutes late Riyard Mahrez put City ahead with a goal from inside the penalty that had a much higher xG as it was a clear shot on goal from inside the box. As you can see from the link above the goals are pink and the shots are in blue and based on all of those shots added together and their chances of finding the back of the next the xG for a match is calculated. One thing to remember though is that it’s a stat to show how many goals a team should score, it’s rather a stat to show how many goals a team would score under normal circumstances, it’s a small difference, but a crucial one.
Using xG in Football Betting
How can we use it in our betting though? Well, there are two sites in particular that we can use, one will give us trustworthy xG data and the other can calculate the odds and implied probability of events occurring.
First of all head here and have a look through the league they have xG data for. Let’s pick a match from next weekend Premier League; Leicester vs Everton. To get Leicester xG let’s just look at their home from and with Everton we’ll look at their away form. Leicester xG is 8.12 over six matches, so that’s 1.35 xG.
For Everton it’s 5.71, also over six matches, so that’s 0.95. Let’s calculate then the probability of events occurring in matches, by going to this website and putting in the xG data.
We have two possibilities on this website, implied probability percentages or betting odds. Since Bet Dynamo also uses percentages, let’s stick with that.
Now, as you can see Leicester are expected to win and the draw is slightly more favoured than Everton taking the three points.
Indeed, the likelihood is that Everton won’t even get on the score sheet. It’s also expected that Over 1.5 goals will be scored but not more than Over 2.5 goals. We can also see that the most likely scores are 1-0, 1-1, 0-0, 0-1, 2-1 and 1-2.
If you compare that to our Bet Dynamo Insights Page we get some very similar results:
We can compare our stats to that of the xG calculator and we can see that there’s no value in Over 2.5 goals and none in BTTS as well. Maybe the value is in opposing these markets?
The lesson here is to keep on trying to improve your betting and to stay up with what’s happening in the world of football statistics so that you can make better, more-informed betting decisions and have as many betting tools in your arsenal as possible.