A refined xG model that accounts for shot placement within the goal — measuring the quality of each shot after it has been taken.
Post-Shot Expected Goals (PSxG) extends the pre-shot xG model by incorporating the actual trajectory and placement of the shot — where within the goal frame the ball was directed. A shot aimed at the top corner of the goal has a higher PSxG than the same shot aimed straight at the goalkeeper, even from the same location.
PSxG is calculated at the moment of contact — before the goalkeeper has moved to react — using the shot's velocity, angle, and placement data from optical tracking systems. It is only computable for shots on target; shots off target or blocked have no PSxG value.
The most important application of PSxG is evaluating goalkeepers. Goals Saved Above Expected (GSAx) = PSxG conceded − actual goals conceded. A goalkeeper who concedes fewer goals than their PSxG against is outperforming expectations — they are making saves on shots that, given placement, should statistically result in goals.
PSxG is a more reliable goalkeeper evaluation metric than save percentage alone, because it accounts for the difficulty of shots faced. A goalkeeper who faces nothing but straightforward central shots will have a high save percentage but low PSxG responsibility.
xG (Expected Goals)
A metric that scores every shot by its probability of resulting in a goal, based on factors like shot location, angle, and assist type.
Save Percentage
The proportion of shots on target that a goalkeeper saves — a basic measure of goalkeeping performance, but noisy over small samples.
Clean Sheet
When a team concedes no goals in a match — a key metric for defenders and goalkeepers in fantasy football and defensive analysis.
xGA (Expected Goals Against)
The expected goals conceded by a team — a measure of defensive quality based on the quality of chances allowed, not just goals shipped.
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