Statistical Reference and Terminology
Statistics
xG - Expected Goals A metric designed to determine the probability of a shot becoming a goal. For instance, a shot right on the goal line will have an xG of .99. A shot with an xG of .1 from outside the box is likely to be a goal only one time for every ten shots taken from that spot. I primarily use FBRef, which gets their xG calculations from Opta.
PSxG - Post Shot Expected Goals, or how likely is a shot going to be a goal based on where it is put on target, rather than the spot on the field where the shot was taken.
xGA - xG Allowed, or what is the xG of the opposing team.
xGD - xG Differential, calculated by subtracting a team’s xGA from their xG.
npxG - Non-penalty xG
xAG - Expected Assisted Goals or the xG generated by a shot following a pass. For instance if Player A pass to Player B, and Player B takes a shot worth .5 xG, Player A gets an xAG of .5.
xA - Expected Assists or the likelihood that a pass will earn an assist. This differs from xAG in that it doesn’t require a shot. For instance, if a player puts a great cross on the ground, through the box, but nobody manages to latch onto it, that pass might have a high xA, but no xAG.
PSxG+/- - This is a goalkeeping statistic that looks at the Post Shot xG, or how likely is that shot to be a goal based on where the shot is heading, and then subtracting the actual number of goals scored. Positive PSxG +/- is indicative of a good goalie, while negative implies that the goalie is saving less than is to be expected.
Save Percentage - The percentage of shots that a goalkeeper saves.
#OPA - The number of defensive actions outside the penalty area.
xG +/- per 90 - The team xG when a player is on the field minus the team xG when the player is off the field. So if the team performs better when a player is on the bench, she’ll have a negative number. If the team is better with her, she’ll have a high positive number.
Key Pass - A pass that directly leads to a shot
Progressive Pass - A completed pass that moves the ball towards the opponents goal line at least 10 yards from its furthest point in the last 6 passes, or any completed pass into the penalty area. Excludes passes from the defending 40% of the pitch.
Progressive Carry - Carries that move the ball towards the opponents goal line at least 10 yards from its furthest point in the last six passes, or any carry into the penalty area. Excludes carries that end in the defending 50% of the pitch.
Through Ball - A completed pass sent between the back defenders into open space.
Switch - Passes that travel more than 40 yds of the width of the pitch
Terminology
These are the ways that I use the following terms:
No 6 - A defensive midfielder.
No 8 - A central midfielder playing with an equal balance of offensive and defensive responsibilities.
No 9 - A prototypical striker, who plays in the center, often with their back to goal.
No 10 - A playmaker who usually is given more of a free role, less defensive responsibilities, and plays centrally behind the No 9.