Overview
The IB Biology Internal Assessment is worth 20% of your final Biology grade — often the difference between a 5 and a 7 when exams go wrong. Unlike past papers, the IA is coursework you control months before exams. This guide explains criteria, structure, and the mistakes moderators see every year.
What examiners mark
For the IB Diploma Programme, five criteria: Personal engagement, Exploration, Analysis, Evaluation, and Communication. Moderators check that your investigation is yours — authentic question, appropriate method, processed data, and honest limitations.
Recommended structure
For the IB Diploma Programme, typical layout: title, research question, introduction, hypothesis, variables, methodology, safety/ethics, raw data, processed tables/graphs, statistical test, conclusion, evaluation (strengths + limitations + extensions). Keep within the 6–12 page guide limit excluding appendices.
Workflow for a top-band IA
For the IB Diploma Programme, pick a narrow, measurable question you can answer with school lab equipment. Pilot the method once. Photograph setup for engagement. Use a statistical test only when justified (e.g. t-test for two means).
Common pitfalls
For the IB Diploma Programme, cookie-cutter topics without personal angle; no uncertainty; correlation presented as causation; copying online IA structures; weak evaluation that only says "more time".
Criterion practice on MarkScheme
Draft sections can be checked against IB assessment language — [get feedback on your IA writing](/mark?subject=ib-biology-sl) where supported, and use syllabus [lessons](/ib/courses/biology-sl) to strengthen methodology and subject vocabulary.
Frequently asked questions
This section covers Frequently asked questions — what IB examiners reward most often in past papers and coursework.
HL vs SL Biology IA?
Same criteria and weighting — depth and complexity should match your level, not a different rubric.
Can I use AI to write it?
No — academic honesty applies. AI-drafted text risks malpractice findings.
Past papers help?
IA skills differ from exams — but Biology past papers plus lessons reinforce data-handling for Paper 2.