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IB Computer Science Drill Guide: Papers 1-2, 75-Minute Pacing, 12-Week Plan
TUTORZONE EXAM DRILL GUIDE · IB COMPUTER SCIENCE (2027 SYLLABUS)
Built on the IB 2027 syllabus: Paper 1 (Theme A concepts plus the pre-seen case study) and Paper 2 (Theme B computational thinking and programming) are both 1 h 15 min, 50 marks, 35% at SL; at HL each is 2 hours, 80 marks, 40%, and Paper 2 adds OOP and abstract data types. The old Paper 3 has been removed, leaving two papers plus the internal assessment. Method only: what each paper tests, the drill order, how to spend 75 minutes, the usual mark losses, the error log and a 12-week timetable. For questions with answers, use the two original mock papers linked below.
How is IB Computer Science assessed, and what does each part carry?
Paper 1 (Theme A + case study): SL 50 marks (A 38 + B 12) (SL 35%／HL 40%); Paper 2 (Theme B computational thinking): SL 50 marks (HL 80) (SL 35%／HL 40%)
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 1 (Theme A + case study) | SL 50 marks (A 38 + B 12) | SL 35%／HL 40% | SL 1 h 15 min / HL 2 h |
| Paper 2 (Theme B computational thinking) | SL 50 marks (HL 80) | SL 35%／HL 40% | SL 1 h 15 min / HL 2 h |
IB Computer Science Paper 1 drilling technique: answer the command term exactly (outline gives the shape, explain gives mechanism plus consequence); show every step of binary/hex conversion (method marks survive); Section B case-study answers must cite specifics from the scenario – generic answers score nothing. Paper 3 no longer exists from 2027.
What each paper is actually testing
| Paper | Drill focus | How marks are lost |
|---|---|---|
| Paper 1 (Theme A + case study) | concepts + case study analysis | Paper 1 answers stay generic: Section B never cites the specific system, figures or constraints in the case study, and the concept questions treat every command term alike – an outline written as an essay, an explain answered with one definition |
| Paper 2 (Theme B computational thinking) | tracing + coding + databases | Paper 2 gives only the final answer: traces list no per-iteration values, code has no variables or edge cases, the B1 question asks for no code and gets code anyway, and OOP answers list attributes with neither methods nor a reason for encapsulation – often with a built-in (sort()) the question forbade |
What is each IB Computer Science paper really testing, and what should you drill?
Paper 1 (Theme A + case study): concepts + case study analysis; Paper 2 (Theme B computational thinking): tracing + coding + databases
Drill order: by topic, then by year, then the mark scheme
| Step | What you do | Why |
|---|---|---|
| 1. By topic | Work through each topic, starting with the paper that allows least help (no calculator / closed book) | Exposes what is genuinely not understood |
| 2. By year | Whole papers to time, one or two a week | Trains pace, stamina and question selection |
| 3. Mark scheme | Go through the marking scheme question by question and log the scoring steps you missed | Most lost marks are written wrong, not thought wrong |
Should drilling go by topic first or by year?
By topic first, then whole papers by year, then the mark scheme. The first third of the time goes topic by topic (8-10 years of the same topic back to back), the middle switches to timed whole papers, and the last fortnight only redoes the recurring errors from your log.
A 12-week drilling timetable
| Week | Phase | What to do |
|---|---|---|
| Weeks 1-3 | By topic: foundation | Topic by topic, starting with the easiest marks, building habits and recall |
| Weeks 4-6 | By topic: core | 8-10 years of the same topic back to back, errors classified by topic |
| Weeks 7-8 | By topic: advanced and electives | Elective and higher-order topics, now under time pressure |
| Weeks 9-10 | By year: timed papers | One full paper a week, timed, no reference materials |
| Week 11 | Mark scheme work | Question by question against the marking scheme; list the scoring steps you omitted |
| Week 12 | Plug holes and simulate | Only the recurring errors from your log, then one full exam simulation |
Subject-specific weighting for this timetable: Twelve weeks in four blocks: Theme A concepts, Theme B programming, the case study, then timed papers. Weeks 1-3 are the Paper 1 concept questions (A1 computer fundamentals, A2 networks, A3 databases, A4 machine learning), each answered to the command term inside its time and checked against the mark description. Weeks 4-6 move to B1 and B2: B1 in written steps only (input, process, output, edge cases), and three hand-written programs a week in B2, each run on a machine. Weeks 7-9 take B3 OOP (one class: attributes, methods, encapsulation) and start the case study for the session, mapping the system, its inputs and outputs and three constraints. Weeks 10-11 are timed whole papers, two each of Paper 1 and Paper 2 at 75 minutes. Week 12 redoes only the recurring error types and drills the answer length each command term expects.
Use it properly: this is not a checklist to finish. Every week must keep time for redoing errors, or from week 9 you will be repeating the same batch.
Pacing
| Paper | Time | Suggested split |
|---|---|---|
| Paper 1 (Theme A + case study) | SL 1 h 15 min / HL 2 h | about 55 min Section A, 20 min Section B |
| Paper 2 (Theme B computational thinking) | SL 1 h 15 min / HL 2 h | includes an algorithmic-thinking question with no code |
How should the time be split inside each IB Computer Science paper?
Paper 1 (Theme A + case study): about 55 min Section A, 20 min Section B; Paper 2 (Theme B computational thinking): includes an algorithmic-thinking question with no code
The drilling mistakes that cost the most marks
| Mistake | What it looks like | What actually happens | Instead |
|---|---|---|---|
| Binary conversion without steps | Final answer only | Show each 4-bit grouping | method marks |
| Generic case-study answer | Theory only | Must cite scenario specifics | cite the scenario |
| Command terms treated alike | Outline written long | Outline gives only the shape | answer the command term |
| Still drilling Paper 3 | Using legacy material | Paper 3 removed from 2027 | only Papers 1 and 2 |
The error log and the mark scheme
Four columns: command term (outline, describe, explain and evaluate all written to the same length), case-study citation (does Section B quote the specific system, figures and constraints), code process (per-iteration values in traces, edge cases handled, no forbidden built-ins) and OOP structure (attributes, methods, reason for encapsulation – which is missing). Three entries in the third column means next week is hand-written code and tracing only; three in the second means copying the case study’s three key constraints onto the draft before every answer.
How many years should you drill?
2027 is the first assessment of the new IB Computer Science course, so there are no past Papers 1 and 2 to drill (the old course was last examined in 2026, and its papers included Paper 3 and four option papers that no longer exist). The order is therefore: build the Theme A/B knowledge map from the official subject brief and textbook examples, then drill the topics that survive from the old course (computer fundamentals, networks, databases, programming basics), and finally rehearse the new shape – the Python and Java versions, and the B1 question that forbids code – on original mocks and school papers. Do not treat old Paper 3 or option papers as “past papers”: those question types are not on the new papers.
How many years of past papers is enough?
2027 is the first assessment of the new IB Computer Science course, so there are no past Papers 1 and 2 to drill (the old course was last examined in 2026, and its papers included Paper 3 and four option papers that no longer exist). The order is therefore: build the Theme A/B knowledge map from the official subject brief and textbook examples, then drill the topics that survive from the old course (computer fundamentals, networks, databases, programming basics), and finally rehearse the new shape – the Python and Java versions, and the B1 question that forbids code – on original mocks and school papers. Do not treat old Paper 3 or option papers as “past papers”: those question types are not on the new papers.
Frequently asked questions
Is this page a mock paper or a drilling guide?
This is the IB Computer Science drilling guide: assessment structure, drill order, a 12-week timetable, pacing, common mark losses and the error-log method. For questions with answers, use the IB Computer Science mock papers linked under Related.
By topic or by year first?
By topic. Eight to ten years of the same topic back to back is what exposes repeating errors; going straight to whole papers just repeats the same batch under time pressure.
How should the error log be written?
Do not copy out questions. Per error record four things: question reference, which step failed (concept, wording, calculation), what the mark scheme requires, and the correct action next time.
Can I still use papers from the old course (2026 or earlier)?
Only as a question-type reference, not as new-paper practice. The old papers had Paper 3 (an HL case-study extension) and four option papers (databases, modelling and simulation, web science, OOP), all removed from 2027; the case study now sits in Paper 1, and Paper 2 always requires programming in Python or Java. The old Theme A concept questions and programming basics are still worth doing; skip the rest.
Do SL candidates need B4 abstract data types?
No – B4 (stacks, queues, linked lists, binary trees and recursion) is HL only. SL covers B1 computational thinking, B2 programming and B3 OOP for a single class. B2 already expects 2D arrays, string handling and file processing at SL, so time spent on B4 is wasted.
Official references
| Resource | What to use it for |
|---|---|
| IB Computer Science curriculum update (IBO) | Confirm the Paper 1/2 marks and times |
| https://www.tutorzone.com.hk/en-ib-psychology-paper-1-mock-2027/ | IB Psychology Paper 1 drilling mock |
Related: IB Computer Science Paper 1 original mock (Theme A plus case study, with answers) · Paper 2 original mock (Theme B, worked answers) · practice area
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