When parents choose a tuition centre, class size is often treated as a secondary consideration — something to ask about after location, subject offerings and price. In reality, it may be the single most important variable in how much your child actually learns.
The research on class size is not subtle. Smaller classes produce better outcomes. The question is understanding why — and what "small" actually means in practice.
The most cited evidence on class size comes from the STAR (Student-Teacher Achievement Ratio) study, a large-scale randomised experiment conducted in Tennessee across 79 schools and nearly 12,000 students. It found that students in smaller classes (13–17 students) significantly outperformed those in larger classes (22–26 students) — and that the benefits were strongest for students who were already struggling.
Subsequent research has consistently supported the finding. A 2019 meta-analysis of class size studies found meaningful positive effects on both academic achievement and student engagement, with the largest effects in the first few years of schooling — though benefits persist through secondary school.
Many tuition centres in Singapore describe themselves as offering "small group" tuition. In practice, this often means 10–15 students — significantly smaller than a school class of 30–40, but still large enough that meaningful individual attention is difficult to sustain.
At 15 students, a teacher conducting a 90-minute class has on average about 6 minutes of individual interaction time per student — and that assumes perfectly even distribution, which never happens. Students who are confused but quiet will receive almost none of it.
At 6 students, the same 90 minutes yields 15 minutes per student on average — and more importantly, teachers can track every student's understanding throughout the class, not just the ones who volunteer answers.
One of the least-discussed benefits of genuinely small classes is that teachers can detect confusion before students articulate it. A student who doesn't understand something may not know they don't understand it — or may be too embarrassed to say so. In a class of 15 or more, this student can remain invisible for weeks.
In a class of 6, an experienced teacher will notice within a session. The student who pauses slightly before copying down a step, who asks a clarifying question phrased in a way that reveals a specific misconception, who gets a right answer for a wrong reason — all of these are visible at 6, invisible at 15.
Over the course of a term, this difference compounds significantly. Students in genuinely small classes accumulate fewer unaddressed gaps. They build on more solid foundations. Their confidence — which is itself a significant predictor of academic performance — is better maintained.
Six students per class is not a marketing number. It is the number at which we believe genuine individual attention becomes reliably possible — not occasionally possible when a student speaks up, but as a structural feature of every session.
We have had conversations about whether to increase class sizes to serve more students and improve margins. Our answer has consistently been no — because the benefits we believe we can deliver are contingent on that number, and we're not willing to compromise on it.
If you're comparing tuition options for your child, the single most useful question to ask is: how many students are in the class, exactly? Not "do you offer small group tuition?" — but the actual number, in the specific class your child would join.
Lumi's small group classes in Bishan and Clementi are built around the six-student class. Come and try a free class — no commitment.
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