Overview
For the IB Diploma Programme, a top-band ERQ answers the exact question in the first sentence, then proves that answer with two or three studies used as evidence and critical thinking woven through every paragraph — not a study dump followed by one thin evaluation. That single blueprint is worth all 22 marks, and this guide shows how to build it under a 45-to-50-minute clock, criterion by criterion.
How the ERQ is marked — the five criteria
The IB Psychology extended-response question (ERQ) is marked out of 22 across five criteria. Knowing exactly what the top band of each one demands is the difference between writing what feels like a good essay and writing what actually scores.
| Criterion | Marks | What the top band needs |
|---|---|---|
| A — Focus on the question | 2 | Identify the problem and demand of the question and stay on task throughout; no drift into unrelated material |
| B — Knowledge and understanding | 6 | Relevant, accurate, detailed psychology with correct terminology used precisely |
| C — Use of research to support the answer | 6 | Relevant studies explained and used to build the argument — not described in an isolated block |
| D — Critical thinking | 6 | Developed, balanced evaluation: methodology, cultural or gender bias, alternative explanations, contradictory findings, real-world application, areas of uncertainty |
| E — Clarity and organization | 2 | Clear, structured and well-organized from start to finish |
The two-mark criteria (A and E) are thresholds — get focus and organization right and you stay in contention, but they will not lift you into the top band. The essay is won or lost on the two six-mark criteria in the middle: C, use of research, and D, critical thinking. Most students who stall at a 5 lose marks in the same two places — they describe studies instead of using them, and they tack on a thin, one-sided evaluation at the end. Fix those two habits and you fix the essay.
The command term sets the demand for criterion A: "discuss" wants both sides, "evaluate" a reasoned judgement, "to what extent" an argument about how far the evidence supports a claim, "contrast" the differences drawn out. Answer the wrong demand and you cap focus and knowledge before writing a word of analysis.
The paragraph structure that scores
For the IB Diploma Programme, every body paragraph in a strong ERQ follows the same five-move shape — learn it once and you can write to it on any prompt:
- Point — a claim that directly answers the question.
- Study explained — the aim, procedure and key findings of a relevant study, in enough detail to count as real knowledge (criterion B).
- Use it — the crucial move: show how the study supports your point. "Because this study found X, we can argue Y about the question." This is criterion C.
- Critical thinking — evaluate the evidence: a methodological strength or limitation, a possible bias, an alternative explanation, or how far it generalizes. This is criterion D.
- Link back — one sentence tying the paragraph to the exact wording of the question.
Two or three paragraphs built like this, plus a short focus statement and a conclusion that gives your judgement, is a complete top-band essay. Criteria C and D are baked into every paragraph rather than saved for a separate section — that is the whole trick.
Criterion C — using research to build an argument
For the IB Diploma Programme, criterion C is about using research, not listing it. The question is not "do you know some studies?" but "does each study earn its place by advancing your answer?" The gap is easiest to see with a before-and-after.
Describing (caps you at mid-band): "Loftus and Palmer (1974) showed participants a car crash video and asked how fast the cars were going using different verbs. Those who heard 'smashed' gave higher speed estimates than those who heard 'hit'. This shows memory can be reconstructed."
Accurate and detailed — it earns criterion B — but it just sits there, never connecting to the specific question.
Using (top band): "On a question about the reliability of memory, Loftus and Palmer (1974) is direct evidence against it. Because merely changing the verb from 'hit' to 'smashed' shifted speed estimates upward, the study shows that post-event wording can distort a memory that was accurately encoded — so eyewitness memory cannot be treated as a fixed recording. This supports the argument that memory is reconstructive rather than reproductive, exactly what the question probes."
Same study, same facts — but the second version names the claim, shows the mechanism, and links back to the question. Two studies used like this out-score four merely parked in the middle of the page.
Criterion D — developing critical thinking
For the IB Diploma Programme, criterion D is where most 5s stall, and it fails in two predictable ways: the evaluation is bolted on at the end instead of woven through, and it is one-sided instead of balanced.
Developed critical thinking draws on a menu of angles — you need a few, applied to your studies rather than recited generically:
- Methodology — lab control versus ecological validity, sample size, control groups, whether the operationalization actually measured the construct.
- Bias — cultural bias (was the sample WEIRD — Western, educated, industrialized?), gender bias, demand characteristics.
- Alternative explanations — could a confound or a rival theory account for the same finding?
- Contradictory findings — does another study point the other way? Naming a genuine tension is high-value analysis.
- Application and uncertainty — where the finding matters outside the lab, its limits, and what the evidence still cannot settle.
"Balanced" is the word that trips people up. A one-sided demolition of every study is as weak as no evaluation at all: if you attack a study's low ecological validity, acknowledge the control the lab setting bought you, then weigh the two sides into a judgement in your conclusion. That weighing — not the length of your critique — is what moves criterion D from a 4 to a 6.
Planning and timing under exam pressure
For the IB Diploma Programme, you typically get around 45 to 50 minutes per ERQ. Spend the first five planning and the essay writes itself faster.
- Minutes 0–5: plan. Underline the command term and topic. Write your one-line answer — that becomes your focus statement. Jot the two or three studies you will use and, next to each, the point it proves and the sharpest evaluation angle.
- Minutes 5–40: write. Short focus paragraph, then body paragraphs to the five-move shape, glancing at the command term as you go.
- Minutes 40–48: conclude and check. A conclusion that gives a balanced judgement, then a quick read for focus and organization (criteria A and E — cheap marks to protect).
If you run short on time, sacrifice a third study before you sacrifice the critical thinking on your first two. Depth of use beats breadth of coverage.
Choosing and banking studies you can deploy
For the IB Diploma Programme, you cannot improvise studies in an exam, so the work happens beforehand. For every study, keep a one-line record: researcher and year, aim, procedure, key finding, one strength, one limitation, and — the part most students skip — which questions it can answer. A single well-understood study often covers several prompts across an approach.
Aim for a compact bank you know deeply rather than a long list you half-remember, and pick studies that are evaluable — ones with an obvious methodological talking point or a contradicting study nearby, because those hand you criterion D for free. Our free IB Psychology SL course and HL course link every syllabus topic to lessons, flashcards and practice tasks, so the bank builds topic by topic.
Common mistakes that cap you at mid-band
This section covers Common mistakes that cap you at mid-band — what IB examiners reward most often in past papers and coursework.
- Describing, not using. The single most common reason ERQs stall — accurate descriptions that never connect to the question. Criterion C rewards use.
- One-sided evaluation. Only attacking (or only praising) is not balanced; criterion D wants both sides developed into a judgement.
- Bolt-on critical thinking. One evaluation paragraph at the end instead of analysis woven through.
- No focus. Drifting off the exact demand, or answering the wrong command term, quietly caps criteria A and B.
- Listing studies. Four name-checked in a row is an inventory, not an argument. Two used well beats four described.
How MarkScheme helps you practise
Self-marking gets you a long way, but the biggest gains hide in the gap between what you think your essay does and what an examiner sees. After a timed ERQ, [get your essay marked](/mark) against the same A–E criteria the IB uses, so you can pinpoint where criterion C and D marks are leaking — is a study described but not used, or is your evaluation one-sided? Pair that with the free [SL](/ib/courses/psychology-sl) and [HL](/ib/courses/psychology-hl) courses to keep filling the study bank, and drill against real [SL past papers](/blog/ib-psychology-sl-past-papers-guide) so the whole learn-practise-mark cycle lives in one place.
Frequently asked questions
This section covers Frequently asked questions — what IB examiners reward most often in past papers and coursework.
How many studies do I need in an ERQ?
Two or three well-chosen studies is the sweet spot. Each needs its aim, procedure and findings explained, and — more importantly — each must be used to answer the question. Two studies genuinely deployed as evidence out-score four you only describe.
How do I get criterion D marks?
Weave balanced, developed evaluation through the essay instead of tacking one paragraph on the end. Apply real angles — methodology, cultural or gender bias, alternative explanations, contradictory findings, application, uncertainty — to your studies, keep both sides in view, and settle it with a judgement that matches the command term.
What's the difference between describing and using a study?
Describing states what the researchers did and found — that earns criterion B. Using takes that finding and shows how it supports a claim about the question ("because the study found X, we can argue Y"), which earns criterion C, where the top-band marks are.
How long should an ERQ take?
Around 45 to 50 minutes: roughly five planning, thirty-five writing, and the last few concluding and checking focus and organization.
Do "discuss" and "evaluate" want the same essay?
No. "Discuss" wants a genuine both-sides treatment, "evaluate" wants a reasoned judgement, and "to what extent" wants an argument about how far the evidence supports a claim. Answer the wrong demand and criterion A suffers. See how to hit the top markbands in essays and IB markbands explained.