Choosing subjects at IGCSE and A Level

Subject choice is the decision families find hardest, partly because it is made twice — once at 14, when almost nothing is closed off, and again at 16, when quite a lot is. Understanding which choice actually constrains the future makes both easier.

At IGCSE and O Level, keep the base broad

At this stage the constraint is not really university entry, it is A Level entry. A student who drops a science or takes only the shortest mathematics route can find specific A Levels unavailable two years later. Practical guidance that holds across most curricula:

• Mathematics and a language of instruction are effectively compulsory.
• Take at least two sciences if any science, medicine, or engineering pathway is conceivable. Three keeps everything open.
• Eight to nine subjects taught well beats eleven taught thinly. Grades matter more than count, and every additional subject taxes the same revision weeks.
• One subject the student genuinely enjoys is not a luxury. It sustains the other seven.

At A Level, work backwards from the destination

Here the logic inverts: start from where the student might apply, and read actual entry requirements rather than assumptions about them. Two patterns are worth knowing.

Some degrees have hard prerequisites. Medicine, dentistry and veterinary science generally require chemistry and usually biology. Engineering requires mathematics and physics. Economics at competitive universities usually requires mathematics. If a subject is a prerequisite anywhere on the shortlist, it is not optional.

Most other degrees are flexible, but reward coherence. Three subjects that tell a consistent story — say, mathematics, economics and geography — read better in an application than three unconnected ones, and make the personal statement easier to write honestly.

Combinations that quietly close doors

A student taking three essay subjects cannot easily move into a quantitative degree later; a student taking three sciences with no writing-heavy subject may find the extended writing in a humanities-adjacent degree difficult. Neither is wrong. Both should be chosen deliberately rather than by drift.

Questions worth asking before deciding

• Which subjects does the student actually want to study for two years?
• What are the real entry requirements for three plausible destinations?
• Is the school strong in the subjects being chosen, and who teaches them?
• Does the combination leave at least two different degree families open?
• What is the plan if one subject proves harder than expected?

If you cannot answer the second question, that is the place to start. Entry requirements are published, specific, and change less than rumour suggests — and reading them yourself will settle most of the debate at home.