The strongest argument for preparing before A Levels is not made by anyone selling preparation. It is written into every Cambridge syllabus, in a section almost nobody opens.

It is called Previous study, or Prior knowledge, and it states what the course expects you to arrive already knowing.

Two kinds of material, treated completely differently

Every syllabus contains two things, and the distinction is the whole point.

Subject content is what the course teaches. It is sequenced, examined, revisited, and there is a professional responsible for it. Cambridge designs a full A Level around about 360 guided learning hours to deliver it, against roughly 130 for an IGCSE.

Assumed prior knowledge is what the course uses without teaching. It appears on day one, inside questions about other things, and no lesson is allocated to it because the syllabus already declared the assumption.

So one body of material has a teacher and the other does not. That is not an oversight; it is the design. And it is why “assumed” is the most consequential word in the document.

What six subjects actually say

Quoted from the current syllabuses rather than paraphrased, because the specificity is the point.

Mathematics 9709 assumes knowledge of Cambridge IGCSE Mathematics 0580 (Extended curriculum), or Cambridge International O Level 4024/4029. It then names two things directly: candidates should be able to carry out simple manipulation of surds, and should know the shapes of graphs of the form y = kxⁿ.

Physics 9702 recommends learners should have completed a course in Physics or Co-ordinated Science equivalent to Cambridge IGCSE or Cambridge O Level. Separately, it prints a mathematical requirements list and states that teaching those requirements should be included in the Physics course.

Chemistry 9701 and Biology 9700 use the same wording for their own subjects, and both accept Co-ordinated Science.

Economics 9708 recommends a course in mathematics equivalent to Cambridge IGCSE Extended or Cambridge O Level. Not Economics.

Business 9609 states: “We do not expect learners starting this course to have previously studied business.”

Psychology 9990 states the same about Psychology.

Literature in English 9695 recommends a course in English equivalent to IGCSE or O Level, and a level of English equivalent to first language English at IGCSE.

Computer Science 9618 recommends a course in Computer Science equivalent to Cambridge IGCSE or Cambridge O Level.

Read that list and the variety is striking. Some subjects require themselves. Some require nothing. One requires a different subject entirely.

Three things the list tells you

Nobody is checking. There is no gate. Your school sets its own entry grades, but the syllabus assumption is not verified at enrolment. A student who has never manipulated a surd can sit in a 9709 class from September, and the first time it matters will be week three.

A grade is not the requirement. Cambridge frames prior study as a completed course, not an achieved mark. This cuts both ways: an A* does not guarantee the specific skills are fluent, and a modest grade does not mean they are absent.

Open entry is not the same as no assumption. Economics 9708 is the trap. It genuinely does not expect prior Economics, which is how it is marketed and taught — while quietly expecting numeracy that some students chose the subject to avoid.

Why fluency is the real standard

The syllabus says “knowledge is assumed”. In practice the bar is higher than knowing.

Assumed skills do not appear as the question. They appear as step two of a question about something else. Cambridge 9709 requires the derivative of xⁿ for any rational n, and exam questions present terms as roots and reciprocals that must be rewritten as powers before you can differentiate at all.

A student who knows index laws but takes thirty seconds over them has spent their attention on the assumed part. A student for whom it is automatic spends the same lesson on the calculus.

Both know the material. Only one of them can use it at the speed the course moves.

That is why “I did that at IGCSE” is a weaker reassurance than it sounds, and why the useful test is not whether you can do something but whether it costs you thinking time.

Why the section is so easy to miss

Given how consequential it is, it is worth asking why almost nobody reads it.

Partly it is placement. Previous study usually sits in a Before you start section near the back, among administrative material about exam series and entry deadlines. Prior knowledge often appears at the front of the subject content, where readers are skimming towards the topics.

Partly it is length. In a document running to eighty pages or more, the assumed knowledge is a paragraph or two. It reads as preamble rather than as a requirement.

And partly it is audience. Syllabuses are written for teachers and exams officers rather than for students, so nothing in the design draws a sixteen-year-old’s eye to the one section that determines their first term.

None of which changes its status. The material named there is used from day one and taught nowhere, and that remains true whether or not anyone read it.

If your school runs an induction, this is a fair thing to ask about directly: which specific skills does the syllabus assume, and where does it say so. A good answer names them.

How to read your own syllabus

Fifteen minutes per subject, and it is free.

1. Go to the Cambridge International website and find your subject and exam years.
2. Open the syllabus PDF.
3. Find Before you start, usually near the back, and read Previous study.
4. Find Prior knowledge, often at the front of the subject content section.
5. Write out every skill named. It will be short.
6. For each, try a question where it appears as a step rather than as the topic, and mark it automatic, slow, or gone.

That final step is the one that produces something actionable, and it is the one students skip.

The variety is the useful part

Reading several of these statements together tells you something no single one does: the assumption is a deliberate design choice per subject, not a formality.

Computer Science 9618 requires a prior Computer Science course, because the theory genuinely builds on IGCSE material. Business 9609 and Psychology 9990 explicitly require nothing, because both are designed to be started cold. Economics 9708 requires mathematics rather than Economics, because the analysis is quantitative even though the content is new.

That variety has a practical consequence for anyone choosing subjects. A subject requiring no prior study is genuinely open, and a student worried about lacking background in it can stop worrying — the syllabus has already said so in writing.

Equally, a subject that does name a prerequisite means it. Computer Science 9618 assumes the IGCSE course, and a student arriving without it is outside the design rather than merely behind.

Checking which category each of your subjects falls into takes a few minutes and settles a surprising amount of anxiety in either direction.

What to do with the result

Anything in the automatic column needs nothing at all.

Everything in the slow or gone columns is the summer’s work, and it is usually a handful of items rather than a page. Three or four sessions a week of about forty minutes, writing full method every time, because 9709 gives no marks for unsupported answers from a calculator.

That comes to roughly twenty hours across a summer. Against 360 guided learning hours of teaching, it is obviously not a head start on the course, and it is not meant to be. It exists so that the material the syllabus declared assumed is actually there when the course assumes it.

If maths is on your list and the diagnosis is the part you would rather not do by guesswork, the Readiness Check in Pre-A Level Mathematics works through the 9709 assumptions and reports which sub-topics are secure.

For how the individual assumed skills feed into specific A Level topics, how IGCSE topics connect to A Level maps the prerequisites, and what to prepare before A Levels separates what a summer can close from what it cannot.

Frequently asked questions

What does Cambridge mean by assumed prior knowledge? +

Material the syllabus expects you to arrive already knowing, so it is used from day one but never taught. It appears in a section headed Previous study or Prior knowledge, usually about a page, and it is separate from the subject content the course actually covers.

Where do I find what my A Level assumes? +

In the syllabus PDF for your subject and exam years, free on the Cambridge website. Look for Previous study, usually in a Before you start section, and Prior knowledge, which often sits at the front of the subject content.

Does Cambridge require a specific IGCSE grade for A Level? +

No. Cambridge states prior study as having completed a course rather than achieving a grade. Mathematics 9709 assumes IGCSE 0580 Extended or O Level 4024/4029 without naming a mark. Any grade threshold you have been given is your school's own entry policy.

Do all A Levels assume prior study of the subject? +

No, and the differences are stated. Computer Science 9618 expects a prior Computer Science course. Business 9609 and Psychology 9990 state they do not expect prior study of the subject. Economics 9708 expects a mathematics course rather than an Economics one.

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