IBDP Subjects • Internal Assessment • Written by the PrepSeven Editorial Team, reviewed by certified IB Examiners

The Complete IB Internal Assessment Guide: How IAs Are Graded

Ask any IB Diploma student which piece of coursework caused them the most stress across two years, and the Internal Assessment is almost always in the running alongside the Extended Essay. Unlike your final exams, which test how well you’ve learned a fixed body of content under time pressure, the IA in each of your six subjects asks something different: can you apply your subject’s methods to a piece of independent, sustained work, and can you critically evaluate what you produce? Every DP subject has its own IA format — a lab report in the sciences, a set of commentaries in Economics, an oral presentation in English, a mathematical exploration in Maths — but underneath these differences sits a common assessment logic that, once understood, makes every subject’s IA far less mysterious. This guide, written by PrepSeven’s certified and former IB examiners, walks through what IAs actually are, how they’re graded, how they fit into your overall subject grade, and what separates high-scoring IAs from average ones across subjects.

What Is an Internal Assessment, and Why Does Every Subject Have One?

An Internal Assessment is a piece of coursework, marked initially by your own classroom teacher and then externally moderated by the IB, that forms part of your final grade in each of your six DP subjects. The core rationale is that certain skills — sustained investigation, primary research, extended oral communication, data collection and analysis — simply can’t be tested well in a timed written exam, no matter how well-designed the exam is. The IA gives you room to demonstrate exactly these skills, under conditions closer to how a professional in that field would actually work.

‘Internally assessed’ doesn’t mean unsupervised or informal — it means your own teacher does the initial marking against the same official IB criteria an external examiner would use, and the IB then reviews a sample of each school’s IAs during moderation to check that marking has been applied consistently and fairly across schools worldwide. If moderation finds a school’s marking is out of line with IB standards, grades across that entire subject cohort can be adjusted up or down accordingly — which is exactly why consistent, criteria-based marking matters so much to your school, not just to you individually.

IA Formats Across Different DP Subjects

While the underlying assessment logic is shared, the actual format of the IA varies significantly by subject group, and it’s worth understanding roughly how your own subjects differ before diving into any single one in depth.

• Sciences (Biology, Chemistry, Physics, ESS): a single extended practical investigation, typically written up as a structured lab report of around 6–12 pages, involving your own research question, data collection (experimental or from a reliable secondary source), analysis, and evaluation.
• Mathematics (AA and AI): a mathematical exploration — a personal investigation into a mathematical topic of your choice, demonstrating both mathematical technique and genuine mathematical curiosity, rather than a re-derivation of a standard textbook proof.
• Economics: a portfolio of short commentaries (typically three at SL, four at HL) applying economic theory and diagrams to real, recent news articles.
• Business Management: a written commentary analysing a real organisational issue or decision, using appropriate business tools and frameworks (SL typically one, HL typically two, depending on the current subject guide).
• Psychology: at SL, an experimental replication study; at HL, this may extend further depending on the current guide — always confirm exact current requirements with your teacher, since Psychology’s IA structure has been revised across syllabus versions.
• English A (Language and Literature / Literature): the Individual Oral — a recorded spoken commentary analysing a literary and/or non-literary extract in relation to a global issue.
• Language Acquisition (Language B): an individual oral assessment discussing a visual stimulus and a broader course theme in the target language.
• Visual Arts: a process portfolio and exhibition of art pieces, rather than a single written report, assessed on artistic development and technical/conceptual skill.

The Underlying Assessment Logic: What Most IA Criteria Actually Reward

Although the specific criterion names differ by subject, most DP subjects assess IAs against some version of the following underlying skills, which is worth understanding because it tells you where to focus your effort regardless of which subject’s IA you’re working on.

Formulating a Focused Question or Aim

Just as with the Extended Essay, a narrow, well-defined research question or investigative aim is the foundation everything else is built on. IAs built around vague or overly broad aims tend to produce unfocused data collection and thin analysis, regardless of subject.

Appropriate Methodology and Data Collection

Examiners assess whether your chosen method (an experimental design, a choice of news articles, a mathematical approach, a business framework) is actually well-suited to answering your question, and whether you’ve collected sufficient, relevant, and reliable data or evidence to support genuine analysis.

Analysis and Application

This is usually the most heavily weighted skill across subjects: correctly and insightfully applying subject-specific tools (statistical tests, economic theory, mathematical technique, literary or business frameworks) to your own data or evidence, rather than simply presenting the data and letting it ‘speak for itself.’

Evaluation and Reflection

Almost every subject’s IA rewards honest engagement with the limitations of your method, alternative interpretations of your evidence, and reflection on what you might do differently — this is very similar in spirit to the EE’s emphasis on critical thinking and the RPPF’s emphasis on genuine reflection.

Presentation and Structure

Clarity, appropriate use of subject conventions (citations, labelled diagrams, correct mathematical notation), and adherence to length or format requirements round out most subjects’ criteria, generally as a smaller but still meaningful component of the total mark.

How IA Marks Convert Into Your Final Subject Grade

Your IA mark is combined with your external exam performance according to a subject-specific weighting set by the IB — commonly somewhere in the region of 20 to 30 percent of your total subject grade, though the exact percentage varies by subject and by SL versus HL, and can be revised across syllabus updates. This means that while your final exams typically carry more overall weight, a strong IA can meaningfully lift a borderline subject grade, and a weak IA can just as meaningfully hold back a subject where your exam performance was otherwise solid.

The Role of External Moderation

After your teacher marks your IA against the official criteria, the IB reviews a sample of IAs from your school (not necessarily including yours specifically) to check that your school’s marking is consistent with global standards. If moderation finds your school has been marking systematically too generously or too harshly compared to the standard, the IB can adjust the marks of the entire cohort in that subject up or down — which is why schools take criteria-consistent marking seriously, and why understanding the actual criteria yourself (rather than just trusting your own sense of whether the work is ‘good’) is genuinely useful preparation.

Common Mistakes Across IA Subjects

• Vague research questions or aims: the same problem that plagues weak Extended Essays shows up just as often in IAs — a question too broad to investigate meaningfully within the required length.
• Insufficient or unreliable data: too few trials in a science experiment, too small or unrepresentative a dataset in a Humanities-based IA, or over-reliance on a single source.
• Description instead of analysis: presenting data, results, or events without meaningfully interpreting what they show or why they matter to the research question.
• Ignoring uncertainty and limitations: particularly costly in the sciences and mathematics, where error analysis and methodological limitations are explicitly rewarded, but relevant across subjects.
• Poor structure and presentation: missing labels, inconsistent citation, unclear organisation, or exceeding word/page limits, all of which cost marks under presentation-related criteria.
• Starting too late: as with the EE, IAs completed under time pressure rarely allow for the kind of iteration and reflection that distinguishes top-scoring work.

A General IA Timeline That Works Across Subjects

1. Early planning: identify a research question or investigative aim, and check its feasibility (access to data, sources, equipment, or interview subjects) before committing significant time.
2. Data collection or research: gather your evidence methodically, keeping detailed records so you can revisit exactly what you did and why during the analysis and reflection stages.
3. Draft analysis: apply the relevant subject-specific tools rigorously, and resist the temptation to simply present data without interpreting it.
4. Draft evaluation and reflection: be honest about limitations and alternative interpretations — this is not an admission of failure, it’s exactly what top markbands reward.
5. Full draft review: get feedback from your teacher (and, if possible, a subject-specialist tutor) against the actual official criteria before finalising.
6. Final polish: check formatting, citations, word/page limits, and labelling conventions specific to your subject before submission.

How PrepSeven Helps With Your Internal Assessments

PrepSeven’s tutors are certified and former IB examiners across every DP subject group, which means we’ve personally marked the exact kind of IAs you’re working on and know precisely what separates a markband 5 from a markband 7 response in your specific subject. Rather than generic writing help, we work through your actual research question, data, and analysis against the real official criteria for your subject.

• Subject-specific IA consultations from tutors who have examined real IAs in that subject
• Feasibility checks on research questions and data access before you commit significant time
• Criterion-by-criterion draft review, matched to your specific subject’s current official IA criteria
• Support with data analysis, statistical methods, and evaluation across sciences, humanities, and maths

Frequently Asked Questions

Q1. How many IAs do I have to complete overall?

You complete one IA per DP subject, so a standard Diploma candidate taking six subjects will complete six separate Internal Assessments, each following that subject’s specific format and criteria.

Q2. Can I improve or resubmit my IA after my teacher has marked it?

This depends entirely on your school’s internal deadlines and policies — many schools build in time for a draft review and revision before the final submission is sent for moderation, but once officially submitted to the IB, it typically cannot be resubmitted.

Q3. Do IAs count differently if I take exams in a different session than originally planned?

IA marks are generally tied to when the coursework itself was completed and submitted through your school, rather than to your exam session specifically, but exact policies around deferred or split exam sessions should always be confirmed directly with your school’s DP coordinator.

Q4. How important is data quantity in science IAs?

Sufficient, reliable data matters more than sheer quantity — a smaller dataset collected rigorously with proper repeated trials and error consideration will typically outscore a larger dataset gathered carelessly, since examiners assess data quality and appropriate analysis rather than raw volume.

Q5. Is it possible to change my IA topic partway through?

Yes, particularly early in the process — many strong IAs go through some narrowing or refinement of the original research question or aim once initial data collection reveals what’s actually feasible, and this is a normal part of a well-managed IA process.

Q6. Do all subjects weight the IA the same percentage of the final grade?

No — IA weighting varies by subject and by SL versus HL, and can be revised across IB syllabus updates, so always check your specific subject’s current official weighting with your teacher rather than assuming a fixed universal percentage.

Q7. What’s the single biggest factor in scoring well on an IA?

Across almost every subject, the combination of a focused, answerable research question and genuine analytical depth (rather than description) in your write-up accounts for the largest share of the difference between average and top-scoring IAs.