Assessment Objectives
Every exam question is tagged with an Assessment Objective (AO1–AO3) that describes the cognitive level required. Higher AO numbers demand more complex thinking. AO4 is used exclusively for the Internal Assessment (IA).
AO1 Demonstrate Knowledge & Understanding
Recall and state facts, definitions, concepts, principles and terminology accurately.
- Facts, concepts, principles and terminology in computer science
- Appropriate methods, techniques and skills for computational thinking
AO2 Apply and Use
Use knowledge in familiar and unfamiliar contexts; carry out procedures and present information.
- Facts, concepts, principles and terminology in computer science
- Appropriate methods and skills to solve problems using computational thinking
- Appropriate methods to present information in computer science
AO3 Construct, Synthesise, Analyse & Evaluate
Produce and critique solutions; weigh evidence; form reasoned conclusions.
- Problem specifications, system requirements, success criteria, testing strategies and programs
- Appropriate techniques to solve a problem
- Relevant data, information and technological explanations for solutions
AO4 Computational Thinking (IA only)
Demonstrate the application of computational thinking skills to solve real-world problems using computer science solutions.
- Used exclusively for the Internal Assessment (IA)
- Not assessed in Paper 1 or Paper 2
Exam Composition
Both Paper 1 and Paper 2 split marks evenly between lower-order (AO1 + AO2) and higher-order (AO3) questions. This same ratio applies at both SL and HL — HL simply covers more content, not a harder mark distribution.
Paper 1
- AO1 + AO2 questions test recall, definitions, calculations, tracing algorithms and short-answer description.
- AO3 questions ask you to evaluate trade-offs, justify decisions, construct diagrams, and discuss solutions in depth.
Paper 2
- Same 50 / 50 split as Paper 1.
- Paper 2 focuses on programming and computational thinking topics.
Exam Strategy Tip
- Half of every paper rewards knowing your content — learn definitions, identify key terms, practise tracing algorithms.
- The other half rewards thinking — practise structuring arguments, comparing alternatives and using evidence.
- Watch the command term! A question saying State needs one line; Evaluate needs paragraphs with evidence.
AO1 Command Terms AO1
AO1 questions test straightforward knowledge and recall. Answers should be concise and accurate — no extended justification is expected unless a higher-AO part follows.
Define AO1
"Give the precise meaning of a word, phrase, concept or physical quantity."
Exam tip: Write a single, tight sentence that captures the essential meaning.
Avoid examples unless specifically asked — the mark is for the definition itself.
Learn the exact IB phrasing for key terms (e.g. "An algorithm is a finite set of well-defined
instructions for solving a problem").
Label AO1
"Add labels to a diagram."
Exam tip: Each label must be placed clearly with an arrow or line pointing
to the correct part of the diagram. Spelling must be close enough to be unambiguous.
Check how many marks are available — that tells you how many labels are required.
List AO1
"Give a sequence of brief answers with no explanation."
Exam tip: One word or phrase per item is usually enough. Do not
waste time explaining — you will not earn extra marks for it and it costs you time.
Match the number of items to the number of marks available.
State AO1
"Give a specific name, value or other brief answer without explanation or calculation."
Exam tip: A single word, phrase or number is sufficient. Like List,
adding explanation will not earn extra marks. Often used at the start of a multi-part question
to set up a later Explain or Evaluate.
AO2 Command Terms AO2
AO2 questions require you to apply knowledge — carrying out a procedure, producing a specific answer, or giving an account in context. More detail is expected than AO1, but deep analysis is not yet required.
Calculate AO2
"Obtain a numerical answer showing the relevant stages in the working."
Exam tip: Always show your working, even if the final answer is wrong —
method marks are awarded for correct intermediate steps. Include units where applicable.
Round only at the final step unless told otherwise.
Describe AO2
"Give a detailed account."
Exam tip: Cover what happens and how it works, but you
do not need to say why (that is Explain). Use correct technical vocabulary.
Aim for one mark-worthy point per mark available. Bullet points or prose are both fine.
Distinguish AO2
"Make clear the differences between two or more concepts or items."
Exam tip: Focus on differences only — similarities are not rewarded
here (Compare is for similarities; Compare and contrast asks for both). A table with two columns (one per item) is a neat way
to organise your answer. State each difference explicitly rather than describing each item
in isolation.
Estimate AO2
"Obtain an approximate value."
Exam tip: An estimate is an informed approximation — show the reasoning
that leads to your figure. Marks are usually given for a sensible method rather than a
single exact answer. State any assumptions you make.
Identify AO2
"Provide an answer from a number of possibilities."
Exam tip: Read the question carefully — there is a definite correct answer
to select, not an opinion to form. Usually a short answer (a name, a term, a line of code).
Brief justification may earn an extra mark if offered, but is not required.
Outline AO2
"Give a brief account or summary (a further mark can be given for adding more detail to your answer)."
Exam tip: Start with the key idea, then add one layer of supporting detail
to pick up the bonus mark. An Outline sits between State (bare fact) and
Describe (full account). Think: "headline + one supporting sentence."
Trace AO2
"Follow and record the actions of an algorithm."
Exam tip: A trace table (one column per variable, one row per step) is the
standard format. Update every variable at every iteration — do not skip unchanged
values. Marks are awarded for correct intermediate states, not just the final output.
Write neatly so the examiner can follow your logic.
AO3 Command Terms AO3
AO3 questions reward higher-order thinking — constructing, synthesising, analysing and evaluating. These carry more marks and require structured, evidenced responses. Simply describing or listing facts is not enough.
Compare AO3
"Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout."
Exam tip: Compare means similarities only (IB Computer science
FAQ, 2026). Each point should be true of both items and name both of them: "Both A and B …".
Differences are not rewarded, and neither are two separate descriptions.
Compare and contrast AO3
"Give an account of similarities and differences between two (or more) items or situations, referring to both (all) of them throughout."
Exam tip: Not on the official list of command terms, but the IB says it can be used
when both similarities and differences matter (it was used in the specimen paper). Give at least one
similarity ("Both …") and at least one difference ("A uses X, whereas B uses Y"), linking the two items
in every point. A table with a similarities column and a differences column works well.
Construct AO3
"Display information in a diagrammatic or logical form."
Exam tip: Produce the correct type of diagram (flowchart, UML, truth table,
binary tree, etc.) as indicated by the context. Label all components clearly. Marks are
awarded for logical accuracy, not artistic quality. Follow IB conventions for shapes and
notation where relevant.
Deduce AO3
"Reach a conclusion from the information given."
Exam tip: Your conclusion must follow logically from evidence
provided in the question — do not introduce outside information. Show the reasoning
chain: "Because X, therefore Y." A bare conclusion without reasoning typically earns
partial credit only.
Discuss AO3
"Offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence."
Exam tip: Present multiple perspectives — advantages and
disadvantages, alternative approaches, or contrasting arguments. Back each point with
evidence or a specific example. End with a clear, supported conclusion. A one-sided
answer cannot achieve full marks.
Evaluate AO3
"Make an appraisal by weighing up the strengths and limitations."
Exam tip: Identify both strengths and limitations — one-sided
answers lose marks. After listing them, make a judgement about the overall value or
suitability. Use specific technical criteria to justify your weighting rather than vague
phrases like "it is good/bad."
Explain AO3
"Give a detailed account including reasons or causes."
Exam tip: Go beyond Describe — always answer why or
how something works or happens. The classic pattern is "X happens because Y,
which leads to Z." Each complete cause-and-effect chain is worth a mark. Avoid just
restating facts without connecting them to reasons.
Justify AO3
"Give valid reasons or evidence to support an answer or conclusion."
Exam tip: State your position first, then provide specific evidence or
reasoning for it. Each reason should directly support the conclusion — tangential points
do not earn marks. Unlike Evaluate, you are defending one position rather than
presenting both sides.
Sketch AO3
"Represent by means of a diagram or graph (labelled as appropriate). The sketch should give a general idea of the required shape or relationship, and should include relevant features."
Exam tip: A sketch does not need to be perfectly precise, but it must show
the correct overall shape, trend or structure and include key labels. Mark axes and
label important points (peaks, intersections, asymptotes). Neatness helps the examiner
award marks — use a ruler for straight lines.
Suggest AO3
"Propose a solution, hypothesis or other possible answer."
Exam tip: There is usually no single correct answer — marks reward
a plausible, reasoned suggestion rather than the exact answer. Apply your
knowledge creatively to the scenario given. Back up your suggestion with a brief
explanation of why it could work.
To what extent AO3
"Consider the merits or otherwise of an argument or concept. Opinions and conclusions should be presented clearly and supported with appropriate evidence and sound argument."
Exam tip: This is the highest-demand command term. Structure your answer as
an essay: introduce the proposition, present evidence for, present evidence
against, then reach a nuanced conclusion that specifies the degree to which
the statement holds ("largely true because…, but limited by…"). Vague conclusions like
"it depends" without elaboration earn minimal credit.