IA foundations
IB IA structure, section by section
Written and cross-checked by IB Diploma graduates: Alexander (41), Alejandro (40), Martina (40), Victoria (38), Martin (35), Maria (34)
· Checked against official IB guidance · Editorial policy
There is no single IB-wide IA template. An Internal Assessment can be a scientific investigation, mathematical exploration, historical investigation, commentary, oral, fieldwork report, portfolio or another subject-specific task. The safest structure is the one that makes the current criteria for your exact subject and assessment session easy to satisfy.
Current science example: first assessment 2025
Biology, Chemistry and Physics now share the same four scientific-investigation criteria at SL and HL. These are assessment criteria, not mandatory section headings; your report can be organized differently as long as the required evidence is clear.
01 Research Design
6 marksDescribe the research question in a specific and appropriate context, explain methodological choices for collecting relevant and sufficient data, address relevant controls and safety/ethical/environmental issues, and give enough procedural detail for the investigation to be reproduced.
02 Data Analysis
6 marksRecord and process data clearly and precisely, use appropriate conventions for tables, graphs, units, decimal places and significant figures, consider uncertainties appropriately, and process data in a way that addresses the research question.
03 Conclusion
6 marksAnswer the research question with a conclusion that is consistent with the processed data and its uncertainties, then justify it through relevant comparison with accepted scientific context such as published values or theory.
04 Evaluation
6 marksExplain specific methodological weaknesses or limitations and their relative impact, then propose realistic improvements that directly address those weaknesses or limitations.
Why you must check your subject
Mathematics. The Internal Assessment is a mathematical exploration with criteria designed around mathematical communication, presentation, engagement/reflection and use of mathematics rather than the four science-investigation criteria above.
History and individuals & societies. Tasks can be investigations, fieldwork, commentaries or other subject-specific formats. Their source work, analysis and reflection requirements are not interchangeable with the science rubric.
Languages and the arts. Internal assessment may involve oral, performance, portfolio or other components rather than a single written investigation.
Curriculum changes. A structure that was correct for an older first-assessment year can become wrong after a course redesign. Always pair the subject name with the assessment session when checking requirements.
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Choose your subject →Sources & verification
Primary-source references used to verify key assessment facts on this page. Last source check: September 22, 2026.
The four-criterion example on this page applies to Biology, Chemistry and Physics scientific investigations from first assessment 2025. It is not a universal IA structure.
- IB — Diploma Programme assessment and examsOfficial overview showing that internal assessment varies across Diploma Programme courses and is criterion-related.
- IB — Biology in the Diploma ProgrammeCurrent Biology curriculum and scientific-investigation context, first assessment 2025.
- IB — Chemistry guide (first assessment 2025)Primary guide for the current Chemistry scientific investigation.
- IB — Physics guide (first assessment 2025)Primary guide for the current Physics scientific investigation.
Common questions
Is the IA structure the same for every IB subject?
No. Internal Assessment tasks, criteria, marks, weighting, format and limits are subject-specific and can change by assessment session. Use your current subject guide as the authority rather than copying a generic IA template.
What are the current Biology, Chemistry and Physics IA criteria?
For scientific investigations from first assessment 2025, the four criteria are Research Design, Data Analysis, Conclusion and Evaluation. Each is worth 6 marks, for 24 marks total, and the same criteria apply at SL and HL.
Should an IA use section headings?
Headings can make a report easier to follow, but a generic heading template is not an IB-wide assessment rule. Organize the work so the evidence and reasoning required by your subject criteria are easy to find, and follow any format requirements in the current subject guide.
How long should an IA be?
It depends on the subject and session. Biology, Chemistry and Physics scientific investigations from first assessment 2025 have a 3,000-word maximum. Other subjects use different word, page, oral or portfolio requirements, so check the current guide for your course.
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