IB Math IA Criteria: How the 20 Marks Are Split

The mark split

Two things fall out of that table immediately. Use of Mathematics is the largest single criterion at 6 marks, so a topic that never demands anything harder than substituting into a formula has capped your score before you start. But Presentation and Mathematical Communication together are worth 8 — more than E — and they are almost entirely within your control regardless of how ambitious your topic is.

Students routinely obsess over the first point and neglect the second. Careful structure, defined variables, labelled axes and consistent notation are eight marks that require diligence rather than mathematical insight.

Criterion A — Presentation (4 marks)

This is about whether the reader can follow you. A strong exploration states its question early, moves through it in an order that makes sense, and finishes by answering the question it asked. The body should run roughly 12 to 20 pages.

The most common way to lose marks here is padding: long introductions about why the topic is interesting, background theory that never gets used, or appendices of raw calculation that belong in the argument or nowhere. Concision is explicitly rewarded.

Criterion B — Mathematical Communication (4 marks)

Notation, not prose. Every variable defined before use, consistent symbols throughout, graphs with labelled and scaled axes, and equations set out properly rather than written inline as sentences.

Small habits carry these marks: say what x represents and in what units, do not silently switch from t to T halfway through, and make sure every figure is referred to in the text. None of this requires better mathematics — only care.

Criterion C — Personal Engagement (3 marks)

Examiners are looking for evidence that the exploration is genuinely yours. That comes through in the choices you make and explain: why this question, why this method over an obvious alternative, what you tried that did not work.

Engagement is not the same as an emotional introduction about loving maths since childhood. It shows in independent thinking — collecting your own data, adapting a standard method to your situation, or testing something the textbook does not.

Criterion D — Reflection (3 marks)

Reflection means analysing why something works, not reporting that it did. The marks sit in interrogating your assumptions, comparing a model against reality, and being specific about limitations.

This is why a topic with genuine uncertainty scores better than one where you know the answer before you start. If there is nothing to question, there is nothing to reflect on, and three marks quietly become unreachable. A meaningful reflection appears throughout the work, not only in a paragraph at the end.

Criterion E — Use of Mathematics (6 marks)

The heaviest criterion, and the one your topic decides. The mathematics has to be relevant, correct, and at a level appropriate to your course — commensurate with the syllabus or slightly beyond it.

Level is judged against your course, so what earns full marks for an AI student may score poorly for an AA student, and vice versa. A useful test at HL: could an SL student follow your exploration unchanged? If yes, the mathematical level is probably too low. Check what your course actually covers on the IB mathematics page or in your subject guide before committing to a topic.

Where to start

Work backwards from Criterion E. Pick the mathematics you find most compelling in your course, form a narrow and genuinely measurable question from it, then check that the question leaves room for Personal Engagement and Reflection. Only then start writing.

If you are still at the topic stage, the IA topic ideas guide covers topics by mathematical area and the overdone ones to avoid. For help judging whether a topic can actually reach the top of Criterion E, that is exactly the kind of question one-to-one sessions are useful for.

Frequently asked questions

How many marks is the IB Math IA out of?

20 marks, which is 20% of your final grade at both SL and HL. They split as Presentation 4, Mathematical Communication 4, Personal Engagement 3, Reflection 3 and Use of Mathematics 6.

Which IA criterion is worth the most?

Criterion E, Use of Mathematics, at 6 marks. It is the single heaviest criterion and it is largely determined by your topic, since a topic that never requires mathematics beyond the routine cannot demonstrate the depth the criterion rewards.

How long should the IB Math IA be?

The body should run roughly 12 to 20 pages. Concision is rewarded under Criterion A, so padding the length with unused background theory or raw calculation works against you rather than for you.

What is the difference between Criterion A and Criterion B?

Criterion A, Presentation, is about the structure and coherence of the whole piece: can a reader follow the argument from question to conclusion. Criterion B, Mathematical Communication, is about the mathematics itself being written properly: defined variables, consistent notation, labelled graphs and correctly set out equations.

How do you get Personal Engagement marks?

By making and explaining genuine choices: why this question, why this method rather than an obvious alternative, and what you tried that did not work. Collecting your own data or adapting a standard method to your situation demonstrates it. An emotional introduction about enjoying mathematics does not.

Does the IA level differ between AA and AI?

Yes. Criterion E is judged against your own course, so mathematics that is appropriately demanding for an AI student may be judged too routine for an AA student. Choose a topic that sits at or slightly beyond your own syllabus.

Can a tutor help with the Math IA?

Yes, and the most valuable point to get help is before you start writing, when the topic is still being chosen. A topic that caps Criterion E caps your total, and that is very difficult to repair once the exploration is written. The work is done over weeks rather than under exam conditions, so it suits one-to-one support well.