Smaller classes and fewer students per teacher were associated with a stronger sense of belonging at school …

„Education systems that reported lower student-teacher ratios showed higher mathematics scores even after accounting for per capita GDP. […] Across all countries/economies, smaller classes and fewer students per teacher were associated with a stronger sense of belonging at school, even after accounting for per capita GDP.“
OECD (Hrsg.), PISA 2022 Results, Vol.II. Learning During – and From – Disruption (2023), S. 176.