Command Words in GCSE Exams: What ‘Describe’, ‘Explain’ and ‘Evaluate’ Actually Want

Two students can know exactly the same biology and walk out of the same exam with different grades. The difference is often not knowledge at all. It is that one of them answered the question that was asked, and the other answered the question they wished had been asked. The word that decides which of those you do is the command word— the verb at the start of the question. “Describe”, “explain” and “evaluate” are not interchangeable ways of saying “write about this.” Each one tells the examiner exactly what they are allowed to give you marks for.

Learning to read command words is one of the cheapest grade improvements available. It costs no extra revision. It just means spending the first three seconds of every question working out what kind of answer the mark scheme is waiting for.

Why the command word is really an instruction to the examiner

When a chief examiner writes a question, they write the mark scheme at the same time, and the command word is what links the two. If a question says “describe”, the mark scheme rewards a sequence of correct observations. If it says “explain”, the same facts earn nothing unless they are joined by reasons. The examiner is not being difficult — they are marking against a scheme built around that specific verb. Answer a “describe” question with a beautiful explanation and you can still lose marks, because the marks on offer were for something you did not do. This is the same principle behind reading the mark scheme itself, which we cover in what a mark scheme actually is.

The command words that matter most

There are more than a dozen command words across the boards, but a handful account for the majority of the marks. These are the ones worth knowing cold.

State, give, name, identify

These want recall and nothing else. One word or one short phrase, no reasoning, no context. If a question says “state one factor that affects the rate of reaction”, the answer is “temperature” — not a paragraph about collision theory. Writing more wastes time you need elsewhere and never earns extra marks. The instruction is asking you to retrieve a fact, so retrieve it and move on.

Describe

“Describe” wants what happens, in the right order, without reasons. Describe the trend on a graph and you say what it does — rises steadily, then levels off after 40 seconds — using figures from the axes. You are not asked why it happens. The classic error is to explain when you were asked to describe: the reasons take time and earn nothing, while the actual marks, for reading specific values off the graph, go unclaimed.

Explain

“Explain” wants reasons. The word “because” should appear, or be strongly implied, in almost every sentence. A useful test: if you could write your answer as a chain of “this happens, which causes this, which causes this”, you are explaining. If your answer is a list of facts with no links between them, you are describing, and an “explain” mark scheme will not reward it. Explaining why an enzyme stops working above 50 °C means naming the cause (the enzyme denatures), the mechanism (the active site changes shape), and the consequence (the substrate no longer fits) — three linked ideas, not one restated three ways.

Compare

“Compare” requires you to talk about both things in the same sentence, using a connective — “whereas”, “in contrast”, “both”. Two separate paragraphs, one on each thing, is not a comparison and often scores half marks at best. “Arteries have thick walls whereas veins have thin walls” is one comparison point. “Arteries have thick walls. Veins have valves.” is two facts that never meet, and a comparison mark scheme is looking for the meeting.

Calculate

“Calculate” wants a number, the correct units, and — crucially — the working that got you there. The working is not decoration. It carries most of the marks, which is why a wrong final answer with correct working can still score highly. This is important enough that it has its own article: how method marks work.

Evaluate, assess, justify, to what extent

These are the top-band command words, and they all want the same thing: two sides weighed against each other, followed by a judgement. It is not enough to list advantages and disadvantages. You have to come down on one side and say why, based on the points you have made. Most students who lose the final marks on these questions do so not because their content is weak but because they stop at “on the other hand” and never reach a conclusion. These almost always appear as extended-response questions — see how 6-mark questions are marked for how the banding works.

Suggest

“Suggest” is the board’s signal that you will not have seen this exact situation before. It is testing whether you can apply what you know to something unfamiliar. There is often more than one acceptable answer, so you are being marked on whether your reasoning is scientifically sound, not on whether you recalled a specific fact. Do not panic when you see “suggest” on a context you do not recognise — that unfamiliarity is deliberate, and the marks are for thinking, not memory.

How to build the habit

The technique is simple to state and takes practice to make automatic: before you write a single word, underline the command word, and say to yourself what kind of answer it wants. Recall? Reasons? A judgement? Then check the mark allocation — a two-mark “explain” wants two linked reasons, a six-mark “evaluate” wants a structured argument. The number of marks is a direct instruction about how much to write.

The fastest way to internalise this is to practise on real questions and see, immediately, which marking points your answer hit and which it missed — because the gap is almost always a mismatch between the command word and what you actually wrote. That is exactly what Exaim does: you answer a real exam-style question, and your response is marked against the board’s mark scheme point by point, so a “describe” answer to an “explain” question shows up straight away, with the reasons you needed to add. Browse the GCSE courses to find your subject and board.