Source: https://www.reddit.com/r/singapore/comments/73cmgi/o_level_bellcurve/

It is well known that the “bell curve” is applied to the O Levels result. The most notorious example is E Maths, where 90+ or high 80s is required for the top grade of A1. The traditional mark of 75 is only enough for B3/B4 in the actual O levels.

Update: According to official sources, “grade boundaries” instead of bell curve is being applied to O Levels / A Levels. Technically, there is a subtle difference between the two since the bell curve refers to the normal distribution in statistics. Hence, technically, “bell curve” is not applied to O levels. However, for laymen, “grade boundaries” and “bell curve” are essentially the same thing, meaning that the percentage of A1s or As is being externally controlled by the examiners in the form of “grade boundaries”. It is definitely **not** the case that 75 marks is sufficient for A1 in ‘O’ Levels, or 70 marks is sufficient for A in ‘A’ Levels. It is being moderated and controlled via the “grade boundaries” determined by Cambridge which depends on the difficulty of the paper and possibly other factors like the cohort’s overall performance.

The quintessential discussion on bell curve in O Levels is this Reddit post: https://www.reddit.com/r/SGExams/comments/c1jqzr/o_levels_no_bell_curve/.

According to multiple users on Reddit, the bell curve estimate for Maths in 2016 is:

Emath: 95Estimated a 92. Was pretty confident that I’ll get an A1. My math teacher even said that it’ll be ~88 due to the difficulty of the paper. Ended up with an A2 zzz.

Amath: 90Paper 1 was tricky but paper 2 was manageable. Same thing as above. Estimated a 87, but got an A2.

“2015 O levels, I got double A1s for both maths.

My E-Math estimate is on 96% and A-Math on 90%.The curve on E-Math is far steeper than A-Math, but if you wanna get the double A1s, grind and aim for perfection.”

For the A2/B3 grade, it is less demanding, but still significantly above 70:

Bellcurve is always unfavourable to E Maths student but kinda favourable to A Maths student.

I think I only got

78-79% for E Mathsand I gotA2in the end.While for

A Maths, I know I only got60-64%and in the endB3.

Other sources like Kiasuparents gave the following estimate:

Even if people minus a lot of marks for working… The emath A1 won’t be less than 85.. The paper is too easy. That’s why They moderate the bell curve up by so much.

And not only my teachers, but teachers in other schools as well have told their students that

if they think a score of ~75 can get them an A1, they should b expecting a B3/B4 instead.

Do you have any experience with the bell curve? Share your experience in the comments below!