Football analytics glossary

Plain-English definitions of every metric used on this site. For how expected points are computed, see the methodology.

Expected goals (xG): Expected goals (xG) measures the quality of the chances a team creates: every shot is worth between 0 and 1 goals based on how likely it was to be scored. A team's xG is the sum of those values — what an average team would have scored from the same chances.
Expected goals against (xGA): Expected goals against (xGA) applies the same idea to the chances a team concedes. Low xGA means a team gives up few good chances; high xGA means it is being opened up regularly.
Expected points (xPts): Expected points (xPts) is how many points a team would earn on average given the chances created and conceded. It is computed with a two-team Poisson model: each side's match xG is treated as a scoring rate, every scoreline is assigned a probability, and xPts = 3 × P(win) + 1 × P(draw). Comparing actual points to xPts shows whether a team is over- or under-performing.
Finishing (Goals − xG): Finishing is goals scored minus expected goals. A positive value means a team is scoring more than the quality of its chances suggests — clinical or fortunate; a negative value means it is being wasteful or unlucky in front of goal.
Defensive luck (xGA − Goals against): Defensive luck is expected goals against minus goals conceded. Positive means a team concedes fewer goals than the chances it allows — good goalkeeping or fortune; negative means it is shipping more than it should.
Δ (Points − xPts): Δ is actual points minus expected points. A large positive Δ marks an overperformer (clinical or lucky); a large negative Δ marks a team that has been unlucky and, on the balance of chances, deserved more.
The Luck Quadrant: The Luck Quadrant plots finishing (goals minus xG) against defensive luck (xGA minus goals against), with the crosshair at the field average. Teams in the top-right are riding their luck at both ends; teams in the bottom-left created and prevented more than their results show, and deserved better.