Expected goals, written xG, puts a probability on a shot. A chance from the six-yard box is worth more than a shot from 30 yards, because shots like the first one become goals more often. Add up every chance a team has and you get that team's xG for the match. It is an estimate of chance quality, not a promise of the next result.
How Expected Goals Works
Each shot is scored from the situation it was taken in: where it was hit from, how it was created, and the kind of chance it was. A shot given 0.30 xG is treated as a chance that has been scored from about 30 times in 100 historically similar shots. Ten weak shots can add up to less xG than two clear chances. The final score can disagree with xG for a long time, because finishing and goalkeeping vary, and because a single match is a small sample.
xG does not include goals that were not shot-based in the way the model expects, and different providers weight the same chance differently. Compare a team with itself over a run of matches, or compare teams inside one provider's tables, rather than mixing two xG numbers from two sites.
Why Expected Goals Matters for Betting
A team that has created more than it has scored is not "due" a goal. The number is a better description of the chances than the scoreline is, which helps when a 1-0 flatters a side that barely shot, or hides a side that missed several good chances. Prices move on results. xG is one way to ask whether the result matched the chances.
How OddAlerts Uses Expected Goals
League tables are on the xG stats pages. The longer walkthrough of how to read the metric is Expected goals explained.
FAQ
Is a higher xG the same as a better team?
Not by itself. xG describes the chances in the matches already played. It does not include who they still have to play, injuries, or the price in front of you.
Can xG be higher than the number of shots?
No. Each shot is worth at most 1.0, and almost every shot is worth less, so the total xG is lower than the shot count unless every shot was a near-certainty.
Related Terms
Chance quality is a different question from both teams to score, and a different question from whether the price is a value bet.