Each ETF depends on an index. Every fund supervisor is proud when he performs higher than his benchmark index. Dominikus Wagner considers the idea to be basically fallacious.
https://www.faz.net/aktuell/finanzen/meine-finanzen/sparen-und-geld-anlegen/fonds-etf-warum-index-vergleiche-in-die-irre-fuehren-19436381.html