GCSE command words: what 'describe', 'explain' and 'evaluate' actually want

Command words are the instruction words at the start of a GCSE exam question — describe, explain, calculate, evaluate — and they tell your child how to answer, not what the topic is. Get the command word wrong and the marks disappear, even when the knowledge is all there.

That last part is the bit that took me too long to understand as a parent. When my daughter lost marks on a science mock, my first assumption was that she didn't know the material. She did. She'd written a perfectly accurate description in answer to a question that said explain — and the mark scheme had no marks to give for it. Nobody had ever sat me down and told me that GCSE papers are written in a small, precise vocabulary, that the exam boards publish a glossary for it, and that the difference between a 4 and a 6 on a question is often the difference between knowing that vocabulary and not.

So here it is — the glossary, decoded, parent to parent. I've used AQA's official command words list for GCSE science as the source, because AQA is the most common board in England and science is where these words do the most damage. The same logic applies across subjects and boards, with small variations I'll flag at the end.

The three that cost the most marks

If your child learns nothing else from this page, it should be the difference between these three.

Describe — say what happens. A describe question wants the facts, the events, or the process, accurately and in order. What it does not want is reasons. "The temperature rises, the particles move faster, the reaction speeds up" — that's a description. No because required.

Explain — say why it happens. This is the one. An explain answer must give reasons, and the single most useful habit a student can build is this: an explain answer should contain the word "because" (or "so", or "therefore"). If it doesn't, it's probably a description wearing an explain costume, and the mark scheme will treat it as one. This describe-into-explain slip is, in my experience watching my own daughter revise, the most expensive five-letters-of-difference in the whole exam.

Evaluate — weigh it up, then judge. An evaluate question wants evidence considered on both sides — for and against — using the information in the question plus your child's own knowledge, finished with an actual judgement. The two classic ways to lose marks: arguing only one side, and weighing both sides beautifully but never landing on a conclusion. The judgement isn't optional decoration; it's the point of the question.

The full list, in plain English

These are AQA's GCSE science command words, grouped by what kind of answer they want. The definitions below are my plain-English versions of AQA's official ones — the meaning is theirs, the translation is mine.

The short-answer family: give, name, write, identify, choose, define. All of these want brevity. Give, name and write signal that a word, phrase or single sentence is enough — no explanation, no description. Identify means name it or pin it down. Choose means pick from the options provided. Define means state the meaning of a term. The trap here runs the opposite way to explain: students write a paragraph where a word would do, burning time they need later in the paper.

The maths-and-data family: calculate, determine, estimate, measure, use. Calculate means work out the answer using the numbers in the question. Determine means use the data or information given to reach an answer. Estimate means give a sensible approximate value. Measure means read off a value for a quantity. And use is sneakier than it looks: when a question says "use the information in the figure", answers that ignore the figure score nothing — the marks are attached to using what's given, not to general knowledge of the topic.

The drawing family: draw, sketch, plot, label, complete. Draw means produce or add to a proper diagram. Sketch explicitly permits roughness — approximately right is the brief. Plot means put given data points on a graph. Label means add the right names to a diagram. Complete means fill in the space provided — a gap in a table, a sentence, a diagram.

The practical family: plan, design, show. Plan means write a method — the steps of an experiment. Design means set out how something will be done. Show means lay out structured working or evidence that leads to the stated conclusion — in maths-flavoured questions this means every step visible, not just the destination.

The thinking family: compare, suggest, predict, justify. Compare requires both things to appear in the answer — similarities and/or differences — and writing about only one of them is the classic way to lose half the marks. Suggest means the situation is new: your child hasn't been taught this exact example, and the question wants them to apply what they do know to it. Predict means give a plausible outcome. Justify means back the answer with evidence from the information supplied — not just assert it.

And one for chemistry: balance means balance the chemical equation. At least that one says what it means.

Why does "suggest" appear on things they've never studied?

Because that's its job, and it's worth telling your child this directly: a "suggest" question is not a sign they missed a lesson. The examiner has deliberately chosen an unfamiliar context to test whether the underlying idea has actually been understood, rather than memorised alongside one specific example. A plausible answer rooted in the right principle earns the marks. Students who don't know this freeze — they assume the question is about content they've somehow never seen, when it's really the same content in a costume.

How to actually practise this

The cheapest revision win I know: take a past paper, ignore the content entirely, and just circle the command word in every question. Then ask one question per circle — "what shape of answer does this want?" One word? A because-sentence? Both sides and a judgement? Working shown? It takes ten minutes per paper and it trains the reading habit that exams actually reward.

The second win is mark schemes. They're free on every board's website, and they show, question by question, what the command word converted into marks. A child who reads three mark schemes for evaluate questions will write a better evaluate answer than one who revises the topic for another hour — because the failure was never the topic.

A note on other boards and subjects

I've used AQA science as the spine of this guide because it's the most common combination, but the system is the same everywhere: the definitions descend from a shared Ofqual list, and AQA, Edexcel, OCR and Eduqas publish per-subject command word pages with very similar meanings. Where it gets subject-flavoured is at the edges — discuss in humanities wants alternative viewpoints aired; evaluate in English leans on textual evidence rather than experimental data. The structure of the demand, though — what vs why, one side vs both, short vs shown working — travels across all of them. If you want the exact list for your child's subject and board, search "[board] [subject] GCSE command words" and use the board's own page, or ask the subject teacher — they'll know which definitions the mark scheme is written against.

If you're still earlier in the journey and deciding between science routes, my guide to Combined vs Triple Science covers how the two compare — including the exam differences where these command words eventually show up.

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I'm building Lightbulb Learning for my own daughter — revision that turns the day's actual class topic into a clear evening session, matched to her exam board and year, with practice questions marked the way real mark schemes mark them, command words and all. If that sounds useful for your child, you can join the early list below and I'll let you know the moment it opens.