Command Words — What the Examiner Expects

Every exam question contains a command word that tells you exactly what the examiner expects. Misinterpreting the command word is one of the most common reasons students lose marks. This lesson covers every command word used in the AQA GCSE Combined Science: Trilogy specification (8464) and explains what each one requires.

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Why Command Words Matter

• The command word determines the depth and style of your answer.
• A 2-mark "describe" question needs a different response from a 2-mark "explain" question.
• Learning command words is one of the fastest ways to pick up marks you would otherwise lose.

Exam Tip: Before writing anything, underline or highlight the command word in the question. This forces you to check what is actually being asked.

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AQA Command Word Table

Command word	What it means	What to do	Typical marks
State	Recall a fact or give a brief answer	Write a short, direct answer — no explanation needed	1
Name / Give / Identify	Recall or select from information provided	One word or short phrase — do not waste time explaining	1
Define	Give the precise meaning of a term	Use the scientific definition — be exact	1–2
Describe	Set out characteristics or features	Say what happens, step by step — do not explain why	2–4
Explain	Give reasons for something	Say what happens and why, using scientific knowledge	2–4
Compare	Identify similarities and/or differences	Write about both things; use comparative words (whereas, however, both)	2–4
Suggest	Apply your knowledge to an unfamiliar situation	The answer may not be directly in the specification — use logic and scientific principles	1–3
Calculate	Work out a numerical answer	Show all working, state the equation, include units	2–5
Determine	Use data or information to find an answer	May involve reading a graph, a table or carrying out a calculation	2–3
Evaluate	Judge the evidence or argument; weigh up strengths and weaknesses	Give advantages and disadvantages, then reach a reasoned conclusion	4–6
Justify	Give reasons to support a conclusion or decision	Back up your answer with evidence or scientific reasoning	2–3
Estimate	Give an approximate value using your knowledge or data	Show your reasoning; an exact answer is not expected but the method must be sound	1–2
Sketch	Draw approximately; key features must be correct	Label axes (graphs) or key parts (diagrams); exact precision is not required	2–3
Plan	Write a method for an investigation	Include equipment, variables, measurements, how to make it a fair test	6
Predict	Give an expected result based on understanding	Use your scientific knowledge; you may or may not need to explain	1–2
Complete	Fill in gaps in a table, diagram or sentence	Check you fill in every gap — marks are often lost by missing one	1–3
Draw	Produce a diagram or graph with accuracy	Use a ruler for straight lines; label clearly	1–3
Label	Add names or values to a diagram	Use lines (not arrows) pointing to the exact feature	1–2
Plot	Mark data points on a graph	Use small, neat crosses (×); do not join them unless instructed	2–3
Design	Plan an experiment or procedure	Include variables, apparatus, method and how to analyse results	4–6
Use information from…	Base your answer on the data or context given	Refer specifically to the information provided — do not rely solely on recall	varies

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Command Word Hierarchy

The diagram below shows how command words increase in cognitive demand, from simple recall to complex evaluation.

flowchart TD
    A["Low demand — AO1 Recall"] --> B["State / Name / Give / Define / Label"]
    C["Medium demand — AO2 Application"] --> D["Describe / Calculate / Compare / Suggest / Determine / Predict"]
    E["High demand — AO3 Analysis"] --> F["Explain / Evaluate / Justify / Plan / Design"]
    B --> C
    D --> E

Exam Tip: Higher-demand command words carry more marks. If you see "evaluate" or "explain", the examiner expects depth — a one-line answer will not score well.

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Common Mistakes with Command Words

Describe vs Explain — The Most Common Error

This is the single biggest source of lost marks across all three sciences.

Command word	What is needed	Example question	Good answer	Poor answer
Describe	Say what happens	"Describe the trend shown in the graph."	"As temperature increases from 20°C to 40°C, the rate of reaction increases. Above 40°C the rate decreases."	"The rate increases because particles have more kinetic energy." (This explains — it does not describe.)
Explain	Say what happens and why	"Explain why the rate increases."	"The rate increases because at higher temperatures the particles have more kinetic energy, so they collide more frequently and with more energy, meaning more collisions exceed the activation energy."	"The rate goes up as temperature goes up." (This describes — it does not explain.)

Exam Tip: If a question says "describe", do not give reasons. If it says "explain", you must give reasons — a description alone will score zero on the "explain" marks.

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Compare — The Two-Sided Rule

When asked to compare, you must mention both items. A statement about only one will not score.

• Wrong: "Enzymes work faster at 37°C."
• Right: "Enzymes work faster at 37°C whereas at 60°C they are denatured, so the rate of reaction is lower."

Use linking words: whereas, however, both, but, on the other hand, similarly.

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Evaluate — A Complete Judgement

"Evaluate" is the most demanding command word. You need to:

1. List advantages (or evidence for).
2. List disadvantages (or evidence against).
3. Reach a conclusion — which side is stronger and why?

Missing the conclusion is a very common error. Without it, you cannot reach the highest level.

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Suggest — Using Logic

"Suggest" questions test whether you can apply your knowledge to unfamiliar contexts. The answer may not be something you have explicitly learned. Do not panic — use scientific principles and the data provided to reason through the answer.

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Worked Example: Spotting the Command Word

Question: "A student investigated the effect of pH on enzyme activity. Describe the results shown in Figure 2 and explain the shape of the curve."

This question contains two command words: