Overview
The IB Computer Science Internal Assessment is worth 25% of your final Computer Science 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, criteria cover planning, solution design, development, functionality (video evidence), testing, and evaluation — product and documentation both matter.
Recommended structure
For the IB Diploma Programme, record of tasks → design (UML, wireframes) → development log → testing plan with normal/boundary/abnormal data → video demo → evaluation against success criteria.
Workflow for a top-band IA
For the IB Diploma Programme, scope a product finishable in time — calendar app, inventory, quiz. Use OOP at HL. Test every feature on video. Client feedback strengthens evaluation.
Common pitfalls
For the IB Diploma Programme, no test evidence; feature creep; code without comments; evaluation vague; academic honesty on borrowed code.
Criterion practice on MarkScheme
Draft sections can be checked against IB assessment language — [get feedback on your IA writing](/mark?subject=ib-computer-science-sl) where supported, and use syllabus [lessons](/ib/courses/computer-science-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.
Language choice?
Java, Python, JS etc. — pick what your school supports and you can test thoroughly.
SL vs HL?
HL expects more complex techniques (e.g. OOP, advanced data structures).
Theory exams?
CS past papers for Papers 1–3 alongside IA build.