Is there Bell Curve in O Level Mathematics?

Paradigm Math School 22

One of the most common terms discussed during the O-level examinations is the existence (or non-existence) of the mysterious, and borderline terrifying concept of the “Bell Curve”

But what exactly is that?

The first thing to note is that, no, there is no Bell-Curve.

There is, however, Grade Moderation.


So, whats the difference?

O level and A Level grades are dependent on a grade boundary decided by the examiners in charge of that year.

O Level Math Bell curve

A bell curve, as the name suggests, is a curve in a bell-like shape.

What happens if an actual bell-curve system is used?

eg. when implementing the bell curve system for subject A

  • the highest grade is a 95
  • the lowest grade is a 70

If you put these grades into the bell curve grading system, the system will take ‘70’ as the lowest end of the spectrum, and hence consider it as an F9 grade. Doesn’t make much sense does it?

So now we know the bell-curve system isn’t used, but then, why the need for moderation?

Now lets say 80% of students taking O-levels score 75% and above for subject A. Should all 80% of them get A1?

Of course not, it wouldn’t make sense because placements in JC and upper-end Poly courses have limited intake. Without moderation, 80% of the cohort might just qualify to ACJC, VJC, etc. making it harder to gauge better performing students among the mass of those who scored 75% and above.

Hence, the term Moderation.

The scores you usually attribute to certain grades,

A1: 75%

A2: 70%

B3: 65%

B4: 60% , etc.

will be moderated to the score of the cohort.

So to limit the A1s, and A2s, the percentage requirements to obtain the grades will now look something like this,

A1: >90%

A2: 78%<x≤90%

B3: 68%<x≤78%, etc.

Note however that the lower ends of the bell curve remains as is.

eg. The C6 grade will remain at 50% even for an easy paper. This is because it doesn’t make sense to fail a student who did manage to score a passing mark of 50%


So in conclusion, there is still a form of moderation being implemented. And yes, unfortunately, that means your grades will still be affected by the performance of your batch-mates.

However, do not let this discourage you! But instead, use it as a guide to aim for improvement 😊

It is more important to be consistent, and take it a step at a time! After all, a little a day is all it takes✨

Cheering you on, The Paradigm team 🫶🏻

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