Every shot carries an expected value. Add them up and you get what a player should have scored. Delta is what is left over, the gap between the goals that actually went in and the ones the model saw coming.
The plot below reads that gap as distance. Everyone above the line outscored their chances, and the ones who do it young are the ones worth watching.
Output minus expectation works the same for a striker finishing chances and a keeper preventing them. The plan is to cover both, not just the attacking end that usually gets the spotlight.
Finishing above expectation is noisy and tends to regress. Delta shows who sustains the gap across seasons, rather than crowning whoever is on a hot run right now.
Built entirely on freely available sources, with the method written down. No black box ratings, no numbers you cannot trace back to where they came from.