What is xGA (Expected Goals Against)? A Clear Guide

What is xGA in football?

Expected goals against, commonly known as xGA, is a metric that assigns a probability value to every shot a team concedes during a match. It measures the likelihood of those shots resulting in goals based on historical data.

Traditional metrics like goals conceded only tell you what actually happened on the scoreboard. In contrast, xGA looks deeper into the underlying performance by assessing the danger of the opportunities the opposition managed to create.

• Measures total defensive quality across a match or season
• Removes the randomness of goalkeeper performance and finishing luck
• Assesses every single shot conceded from open play and set pieces

How is expected goals against calculated?

xGA is calculated by analysing thousands of historical shots and weighing specific variables for every attempt an opponent takes against a team. Providers like Opta, FBref, and Understat process these variables automatically.

Each variable contributes to the final xGA value assigned to a shot, building a cumulative total for the match or season.

• Shot distance from the goal line and central angle
• Part of the body used, such as foot or header
• Type of assist or build-up play preceding the shot
• Game state and defensive pressure applied by nearby players

How does xGA separate good defences from lucky ones?

xGA separates genuinely good defences from lucky ones by highlighting whether a low goals-conceded tally stems from solid tactical organisation or simply poor finishing from opponents. Football is a low-scoring sport where random variance plays a massive role.

If a team concedes very few actual goals but has a high xGA, they are likely benefiting from fortunate finishing or exceptional, unsustainable saves from their goalkeeper. Over time, regression usually occurs.

• Low goals conceded + low xGA = Genuinely elite defensive structure
• Low goals conceded + high xGA = Fortunate defence relying on luck
• High goals conceded + low xGA = Unlucky defence let down by variance

How do you read xGA alongside normal xG?

You read xGA alongside normal expected goals (xG) by comparing a team's offensive output against their defensive concession to determine overall performance balance. This creates a complete picture of team dominance.

By subtracting a team's xGA from their xG, analysts calculate the expected goal difference (xGD), which is one of the most reliable indicators of future league table placement.

• xG shows the quality of chances a team creates for themselves
• xGA shows the quality of chances a team allows opponents
• The balance between the two dictates long-term success