„Across education systems, PISA 2022 results show that high-performing education systems were populated with high-quality teaching and non-teaching staff in sufficient numbers. Systems where more teachers were fully certified by an appropriate authority tended to score higher in mathematics, even after accounting for per capita GDP, across OECD countries.“
OECD (Hrsg.), PISA 2022 Results, Vol.II. Learning During – and From – Disruption (2023), S. 170.