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IB ESS Paper 1: Case Data into the Systems Model
A case study is only worth marks once the systems model carries it
Paper 1 works from case material and data, testing whether real material can be carried back into the systems model. The usual loss is quoting numbers and stopping: no trend, no limitation, no link to inputs, outputs and feedback. Every paragraph needs one sentence naming the systems relationship it shows.
How is IB ESS Paper 1 assessed, and what does each part carry?
Paper 1 (case study data analysis): all questions compulsory: analyse and evaluate the case-study data; 1 (SL 25% / HL 30%); Paper 2 (short answer and structured essays): Section A short-answer and data questions, all compulsory; Section B s (50% (SL/HL))
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 1 (case study data analysis) | all questions compulsory: analyse and evaluate the case-study data; 1 hour and 25% at SL, 2 hours and 30% at HL | SL 25% / HL 30% | SL 1 h / HL 2 h |
| Paper 2 (short answer and structured essays) | Section A short-answer and data questions, all compulsory; Section B structured essays with a limited choice; 2 hours at SL and 2.5 at HL, 50% at both | 50% (SL/HL) | SL 2 h / HL 2.5 h |
Paper 1 technique: with a case study, first copy out the key figures (area, rates, concentrations, prices), then calculate and always give units. Evaluation answers should cover ecological, economic and social dimensions and quote the data. At SL allow about 1.5 minutes per mark; at HL the material is longer, so skim it before answering. HL candidates should be ready with the three lenses: environmental law (compensation and regulation), environmental economics (PES, carbon pricing, externalities) and environmental ethics.
What each paper is actually testing
| Paper | Drill focus | How marks are lost |
|---|---|---|
| Paper 1 (case study data analysis) | copy the data, then calculate and evaluate | Numbers quoted with no trend and no limitation. |
| Paper 2 (short answer and structured essays) | clear Section A first, keep half the time for essays | The command term misread, describing where evaluation was asked. |
What is each IB ESS Paper 1 paper really testing, and what should you drill?
Paper 1 (case study data analysis): copy the data, then calculate and evaluate; Paper 2 (short answer and structured essays): clear Section A first, keep half the time for essays
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: Weeks 1-3: a command-term table, one answer skeleton each for describe, explain, evaluate and discuss, circling the term before writing.\nWeeks 4-6: case cards in four lines, location and scale, key data, systems linkage, one limitation.\nWeeks 7-9: data reading, one trend sentence, two limitations, then the link back to the model.\nWeeks 10-12: two timed questions a week until every paragraph carries a systems sentence, then unseen cases in the final fortnight.
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 (case study data analysis) | SL 1 h / HL 2 h | about 1.5 min per mark at SL |
| Paper 2 (short answer and structured essays) | SL 2 h / HL 2.5 h | about 50 min on Section A |
How should the time be split inside each IB ESS Paper 1 paper?
Paper 1 (case study data analysis): about 1.5 min per mark at SL; Paper 2 (short answer and structured essays): about 50 min on Section A
The drilling mistakes that cost the most marks
| Mistake | What it looks like | What actually happens | Instead |
|---|---|---|---|
| Sequestration divided instead of multiplied | Writing 12,000 / 3.2 | The total is area x rate | 38,400 tonnes of carbon a year |
| Loss period inverted | Using 480 / 12,000 | Years = area / annual loss | 25.0 years |
| Multiple reported as a percentage | Writing 2.4 as 2.4% | A multiple is a division of totals | 2.4 times |
| Removal rate over the outflow | Using 12.6 as the denominator | The removal rate uses the inflow of 42.0 | 70.0% |
| Evaluation limited to revenue | Ignoring carbon, flood protection and biodiversity | Compare service value with development income | services worth 2.4 times aquaculture |
The error log and the mark scheme
Three columns: the question and the case used; the systems relationship that should have been named; whether the loss was command term, data, linkage or limitation. Command-term slips get the stem copied out and the skeleton rewritten.
How many years should you drill?
Cases change every year and old data goes stale, while the question shapes and command terms stay stable, so five years is used to learn the asking pattern with recent material substituted in.
How many years of past papers is enough?
Cases change every year and old data goes stale, while the question shapes and command terms stay stable, so five years is used to learn the asking pattern with recent material substituted in.
Frequently asked questions
Is this page a mock paper or a drilling guide?
This is the IB ESS Paper 1 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 ESS Paper 1 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 concepts alone carry an answer when the case is unfamiliar?
Concept marks run out quickly. Each answer needs one named case and one figure, with systems reasoning doing the rest.
Must a data question always include a graph?
Only when asked. For a trend description, state direction, size and period in words, since a wrong sketch reads as a misunderstanding.
Official references
| Resource | What to use it for |
|---|---|
| IB ESS subject brief (first assessment 2026) | Confirm the times, weightings, internal assessment and HL lenses |
| IB official ESS curriculum page | Check the syllabus topics and assessment model |
| https://www.tutorzone.com.hk/en-ib-ess-paper-2-mock-2027/ | IB ESS Paper 2 short answer and essay drilling mock |
Related: practice area · IB ESS Paper 2 drilling mock
Next step: find a tutor / register as a tutor
After drilling, the hard part is telling a conceptual error from a writing error. Tell us the year group, the school and your available times, and TutorZone will match you with a tutor who knows the HKEAA assessment requirements.
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