The Ministry of Education (MOE) should consider reducing class sizes to about 20 to 25, Non-Constituency MP Leon Perera told Parliament yesterday.

He filed a motion to speak on the future of education, and cited academic studies that had shown how smaller class sizes could improve grades and students' holistic development.

"Smaller classes may help level the playing field and enhance equality of opportunity for students from disadvantaged families," said Mr Perera, who called on the MOE to conduct a trial here to find out if such reduced sizes could improve students' results.

Currently, there is an average of about 34 students per class in primary and secondary schools here, except for Primary 1 and 2 levels, which have an average of 29 pupils.

He noted that Education Minister (Schools) Ng Chee Meng said in a previous parliamentary exchange on the same issue that smaller class sizes can be found in situations like remedial classes, or subject-based banding, which allows students to take subjects at different levels according to their strengths.

However, attending remedial classes may stigmatise lower-performing students and affect their self-confidence, and it also eats into students' free time, said Mr Perera, whose parents were primary school teachers.

In response, Mr Ng said that research on the impact of class size on student achievement has not thrown up conclusive findings.

"It is teachers and how they teach that makes a critical difference, not just the class size," said Mr Ng. "We should not fixate on a single dimension of success in education."

Instead of reducing class sizes, MOE invests in teacher quality, which is the most decisive factor in educational outcomes, said Mr Ng. This is backed by research from the Organisation for Economic Co-operation and Development (OECD), he said.

Over the last decade, Singapore's teaching force has grown by 20 per cent. Current student-teacher ratios are 1:12 and 1:16 for secondary and primary schools respectively, which are comparable with OECD standards.

"Instead of reducing class sizes across the board, schools deploy teachers flexibly into smaller sizes for students who need the extra support," said Mr Ng.