Every shot is priced by what shots like it are worth: location, context and the situation it came from, fitted on possession-level play-by-play and anchored to each season's own league rate. A player's number is the gap between what he produced and what those looks were worth, which is why it is called over expected.
The model is leak-free: nothing that happens after a shot is an input to valuing it, and the fit is cross-validated by season so a player's own results never price his own shots.
What this does not measure: it cannot separate playstyle from contact-seeking skill from officiating, and it is not evidence of bias in any direction.
Over Expected is a basketball shot-value platform covering NBA, EuroLeague, EuroCup, Liga ACB, Lega Basket Serie A, Basketball Bundesliga, Greek Basket League, ABA Liga, WNBA.