What programming language does IB Computer Science use?

Written papers use IB's own examination pseudocode, not a named language. Java appears in the Object-Oriented Programming option (Paper 2, Option D). The Internal Assessment can be written in almost any language your school supports — Python, Java, JavaScript, or a database-driven tool — because it is marked on process and documentation, not on language choice.

What is the difference between SL and HL Computer Science?

Both sit Paper 1 and Paper 2 and complete the same Internal Assessment. HL adds Topics 5–7 (abstract data structures, resource management, control systems), extra HL-only material in the option, and Paper 3, which is based on a case study released by the IB each year.

How is the Internal Assessment marked?

Against five criteria: planning, solution overview, development, functionality and extensibility (shown in a screencast), and evaluation. The recommended workload is around 30 hours. Most lost marks come from thin design documentation and evaluations that ignore client feedback, not from the code itself.

Do I need to memorise the HL case study?

No. Paper 3 asks you to apply concepts from the case study to new situations, so you need to understand the technology it covers and the technical vocabulary in the released glossary well enough to reason with it under exam conditions.

IB Computer Science

AP / IB · Computer Science

IB Computer Science is assessed very differently from other programming courses: you write answers in IB's own pseudocode rather than a real language, you answer to command terms and markbands, you sit an options paper on top of the core, and you produce an Internal Assessment worth 30% (SL) or 20% (HL). These sessions work through the SL/HL core topics, the option your school teaches, HL abstract data structures and resource management, and — for HL — the annually released case study. Sessions are spoken one-on-one with an AI tutor, so you can talk through a network diagram or a recursion trace out loud and be pushed on the wording of your answer.

Start a session on IB Computer Science

What this covers

Reading and writing IB examination pseudocode: arrays, collections with hasNext/getNext/resetNext, and the loop patterns examiners expect in Paper 1
Core Topics 1–6: system fundamentals and stakeholder issues, primary/secondary memory and the machine instruction cycle, packet switching and network protocols, boolean logic and binary/hex conversion, and translating a problem into an algorithm
HL Topics 5–7: stacks, queues, linked lists, binary trees, recursion traces, plus resource management, scheduling and the role of the operating system
Your Paper 2 option — Databases (normalisation, transactions), Modelling and Simulation, Web Science, or Object-Oriented Programming in Java
The Internal Assessment: scoping a problem with a real client, success criteria, record of tasks, design overview, development justification and the evaluation
HL Paper 3: extracting the underlying concepts from the case study and applying them to unseen scenarios rather than reciting research

Where learners get stuck

Writing exam answers in Java or Python syntax instead of IB pseudocode: Students who learned to code elsewhere default to the syntax they type daily. IB pseudocode has specific conventions — loop while, end loop, output, and the collection access methods — and examiners mark against constructs, so mixed-syntax answers lose method marks even when the logic is correct.
Treating the IA as 'build something impressive': The criteria reward a documented, client-driven development process, not code difficulty. Learners spend weeks adding features and then lose marks on Criterion B design overview, the record of tasks, or an evaluation that lists no client feedback and no realistic extensions.
Confusing an abstract data structure with how it is stored: A stack is defined by push/pop behaviour, but it can be implemented with an array or a linked list. Questions asking students to 'discuss the use of a linked list rather than an array' expect trade-offs in insertion cost and memory allocation; students often answer by describing what a linked list is instead.
Answering 'describe' and 'evaluate' questions the same way: Command terms carry mark weight. A two-mark 'outline' and a six-mark 'evaluate' about, say, RAID or virtual memory need different structures, and students who write one dense paragraph for both are capped by the markband.

What a session looks like

You talk through problems aloud with the tutor. A typical session might start with a past-paper question on the machine instruction cycle, move into you dictating pseudocode line by line while the tutor checks your loop conditions and array indices, then finish by rewriting a weak six-mark answer with the command term in mind. For IA work, the tutor asks the questions a moderator would: who is your client, which success criterion does this feature meet, what evidence do you have. Sessions can also trace recursive calls or walk a query through a normalised schema step by step.

Helpful to know first

Enrolment in or preparation for IB Computer Science SL or HL, and knowing which Paper 2 option your school teaches
Basic programming in any language: variables, conditionals, loops, functions and arrays
Comfort with binary and hexadecimal number bases, or willingness to review them early
For HL, some prior exposure to objects and classes before starting abstract data structures

Questions

What programming language does IB Computer Science use?: Written papers use IB's own examination pseudocode, not a named language. Java appears in the Object-Oriented Programming option (Paper 2, Option D). The Internal Assessment can be written in almost any language your school supports — Python, Java, JavaScript, or a database-driven tool — because it is marked on process and documentation, not on language choice.
What is the difference between SL and HL Computer Science?: Both sit Paper 1 and Paper 2 and complete the same Internal Assessment. HL adds Topics 5–7 (abstract data structures, resource management, control systems), extra HL-only material in the option, and Paper 3, which is based on a case study released by the IB each year.
How is the Internal Assessment marked?: Against five criteria: planning, solution overview, development, functionality and extensibility (shown in a screencast), and evaluation. The recommended workload is around 30 hours. Most lost marks come from thin design documentation and evaluations that ignore client feedback, not from the code itself.
Do I need to memorise the HL case study?: No. Paper 3 asks you to apply concepts from the case study to new situations, so you need to understand the technology it covers and the technical vocabulary in the released glossary well enough to reason with it under exam conditions.