What is non-penalty xG (npxG)? A cleaner look at attacking quality
Non-penalty expected goals in one sentence, why penalties are stripped out, what npxG reveals about a striker's open-play quality, and how to read it sensibly.
The idea in one sentence
Non-penalty expected goals, or npxG, is simply expected goals with penalties removed. It adds up the quality of every chance a player or team creates except spot-kicks, giving a measure of attacking threat from open play and set pieces alone. The aim is to judge how dangerous a side is in the run of play, without letting a tally of penalties distort the picture of how well it actually creates chances.
Why penalties are stripped out
A penalty is worth a large, fixed chunk of expected goals, because spot-kicks are scored the large majority of the time. That makes them very different from a chance carved out in open play. A player who takes his team's penalties can pile up expected goals without doing anything creative in general play, so leaving penalties in can flatter him. Removing them isolates the part of scoring that comes from genuine attacking work.
What it reveals
npxG is especially useful for comparing strikers and forwards fairly. Two players might post similar expected goals, but if one earns much of his from penalties, his non-penalty figure will be far lower, revealing that his open-play threat is more modest. It also helps judge teams: a side with strong npxG is creating good chances from the run of play, a more repeatable skill than winning and converting penalties.
How to read it sensibly
Like all expected metrics, npxG is most meaningful over many matches rather than one, and it should be read alongside actual output. Penalty-taking is a real and valuable skill, so npxG is not about dismissing it, only about separating it. Comparing a player's npxG with his non-penalty goals shows whether his open-play finishing is running hot or cold, independent of anything happening from the spot.
Where you will see it
npxG appears throughout scouting and player analysis, usually shown next to standard xG so the influence of penalties is clear at a glance. It is a favourite of analysts trying to judge a forward's underlying quality rather than a flattering headline number. For anyone comparing attackers or teams on a fair basis, non-penalty expected goals is one of the cleanest measures of how much danger they create in normal play.