IB Internal Assessment Tutor

The International Baccalaureate (IB) Internal Assessment (IA) is a compulsory, teacher-marked and externally moderated component of every Diploma Programme subject, completed during the two-year course and submitted ahead of the May or November session. It carries 20% of the final grade in the Group 4 sciences and Mathematics: analysis and approaches, 30% in Economics (Standard Level) and 25% in History (Standard Level), enough to shift a final grade by a full boundary.

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What the Internal Assessment Requires

Each IA is assessed against a set of criteria that are unique to the subject. In the sciences (Biology, Chemistry and Physics), the single Scientific investigation is worth 20% of the final grade at both Standard and Higher Level under the syllabus first examined in 2025. In History, the Historical investigation is worth 25% of the final grade at Standard Level under the syllabus first examined in 2017. In Mathematics: analysis and approaches, the Exploration is worth 20% of the final grade at both levels under the syllabus first examined in 2021. The specific criteria descriptors differ by subject, so a student should mark their own draft against their own subject's current criteria rather than a generic checklist. These are not interchangeable. A student who writes a strong general essay or a competent science report may still score poorly if they have not understood what the specific criteria are actually asking for.

The IA also requires a topic that is genuinely investigable within the constraints of the format. In the sciences, this means a research question that can be answered through primary data collection with controlled variables. In Mathematics, it means an exploration with a clear personal angle and sufficient mathematical sophistication for the level. In History, it means a focused historical question that can be addressed through source analysis and secondary research within the IB's word limit for the Historical investigation. Choosing the wrong kind of topic — too broad, too descriptive, or not suited to the format — is one of the most common and costly mistakes students make.

How Much Weight Each Subject's IA Carries

The Internal Assessment's share of the final grade is set by the IB for each subject and published in its own Diploma Programme subject brief - the short reference document the IB itself distributes for every course. The table below is drawn directly from those briefs, with the Standard Level (SL) and Higher Level (HL) weighting shown separately where the two differ, and the syllabus year each subject was first examined under its current assessment model.

In the three Group 4 sciences - IB Physics, Biology and Chemistry - the Internal Assessment is a single Scientific investigation: an open-ended, student-designed enquiry written up as a report capped at a maximum of 3,000 words, worth 20% of the final grade at both SL and HL under the syllabus first examined in 2025. In Mathematics: analysis and approaches, the equivalent component is the Exploration, also worth 20% at both levels under the syllabus first examined in 2021; a student taking IB Maths should check which of the two mathematics courses - analysis and approaches, or applications and interpretation - they are enrolled on, since the assessment models differ. In Economics, the IA is a portfolio of three commentaries, each analysing a different published extract from the news media using a different key economic concept, worth 30% of the final grade at Standard Level under the syllabus first examined in 2022 - not a single commentary. In History, the Historical investigation is an enquiry into a topic of the student's own choice, worth 25% of the final grade at Standard Level under the syllabus first examined in 2017. In Psychology, the experimental study is worth 25% of the final grade at SL and 20% at HL, where an additional written paper reduces its share; a student working on IB Psychology IAs needs to design, run and report a simple experiment while following the IB's ethical guidelines. In Language A: language and literature, the individual oral - a recorded response linking one literary work and one non-literary body of work to a common global issue - is worth 30% of the final grade at SL and 20% at HL, both under the syllabus first examined in 2021.

Where Students Most Often Go Wrong

• Misreading the criteria: Students often write what feels like a strong piece of work without checking whether it actually addresses each criterion. Evaluation in the sciences, for example, requires specific discussion of methodological limitations and realistic improvements — not a general conclusion.
• Choosing an unworkable topic: A research question that is too broad, too descriptive, or reliant on data that cannot be collected within school constraints will limit the mark regardless of how well it is written.
• Weak personal engagement: Several subjects explicitly assess whether the student has demonstrated genuine intellectual curiosity and independent thinking. Formulaic or generic approaches score poorly here.
• Poor structure and presentation: In Mathematics and the sciences, correct labelling of graphs, tables, and units is assessed directly. In History and Economics, the organisation of the argument affects the Communication or Structure criterion.
• Leaving it too late: The IA requires multiple drafts. Students who begin close to the deadline rarely have time to act on teacher feedback or refine their analysis meaningfully.

How the Assessment Is Marked

Your teacher marks your IA using the official IB markbands for your subject. A sample of work from each school is then sent to an external IB examiner, who moderates the teacher's marks. If the examiner finds a consistent pattern of over- or under-marking, all marks from that school are adjusted accordingly. This means your final mark is not simply your teacher's judgement — it is calibrated against the global IB standard. Students whose work genuinely meets the criteria at the top of each markband are protected by this process; students whose work has been generously marked by a teacher may find their grade adjusted downward.

Our IB Internal Assessment specialists support students across all subjects with the design, data collection, analysis, and write-up stages of their IAs, helping them produce work that meets the IB's specific assessment criteria. We're rated 4.8/5 on Trustpilot. Book a free consultation to discuss your child's subject and where they need most support in the IA process.

Understanding the markbands — not just the criteria headings — is therefore essential. The difference between a 3 and a 4 out of 4 on a given criterion is often a specific quality of analysis or a particular type of reflection that the markband descriptor makes explicit. Tutors who know the IB system can help students understand exactly what those descriptors require.

The IB runs two examination sessions each year: the May session, sat mainly by schools following a Northern Hemisphere academic year, and the November session, sat mainly by schools in the Southern Hemisphere. A student's Internal Assessment is submitted electronically by their school ahead of the deadline set for whichever session the student is registered for, and the same teacher-mark-then-external-moderate process applies to both - neither session is an easier route to the same grade boundaries.

How Tuition Helps — and What It Cannot Do

A tutor from Leading Tuition will work with you on the process and understanding that underpin a strong IA. This means helping you interpret the assessment criteria for your specific subject, evaluate whether your chosen topic is appropriate, plan a methodology or structure that fits the format, and improve the quality of your analysis and reasoning through the drafting process. Tutors can review drafts and give detailed feedback on where your work meets the criteria and where it falls short — the same kind of diagnostic reading an experienced examiner would apply.

What a tutor cannot do — and will not do — is write any part of the IA for you. The IB's academic integrity policy is clear, and the consequences of a breach are serious. All work submitted must reflect your own understanding and effort. Tuition develops your ability to produce that work to the highest standard; it does not substitute for it. The IA is one part of a wider IB Diploma: if your child also needs support in other subjects or with the Extended Essay or Theory of Knowledge, our full IB tuition range covers every Diploma subject and component.

Reviewed September 2026: Internal Assessment weightings, formats and first-examination years checked against the International Baccalaureate Organisation's own Diploma Programme subject briefs (ibo.org).

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