Are Premier League players really better? Cross-league strength adjustments

The Big-5 league per-90 stats currently feed Model 4's percentile ranker directly. A goal in EPL is harder to score than a goal in Ligue 1 — the leagues have different strength-of-opposition distributions. Treating them as equivalent depresses EPL players' ranks relative to their true level and inflates ranks at the bottom of the Big-5 hierarchy.

The fix: pull each row's per-90 offensive stats through a multiplicative adjustment derived from ClubElo per-league mean strength, before the percen…