What is the ideal class size? Is smaller necessarily better?
Apart from optimising public resources, reducing class size to increase student achievement is an approach that has been tried, debated, and analysed for several decades. Some countries like Finland favour smaller class sizes (20 students of fewer) and are among the most successful countries in the PISA study. However, other countries like Korea have much bigger classes (34 students and over) but also feature at the top of the PISA ranking. What other variables than class size may explain the success of countries like Korea?
Findings from the OECD Programme for International Student Assessment (PISA) suggest that systems prioritising higher teacher salaries over smaller classes tend to perform better, which confirms research showing that raising teacher quality is a more effective measure to improve student outcomes.
Education indicators in focus
In a period of economic crisis and tightened public budgets, while analyses
of OECD data do not establish a significant relationship between spending per student and
average learning outcomes across countries, PISA data shows that high‑performing education
systems are commonly prioritising the quality of teachers over class size.