IGCSE Command Words Guide
What Examiners Want — How to Answer the Key Command Words
Based on the command word definitions in Cambridge IGCSE syllabuses
Subscribe for Your Free Command Words Guide
Subscribe with your email to unlock the full guide and the printable PDF.
State
Give a brief answer without explanation...
Explain
Give reasons for something happening...
The Golden Rule
Always match your response to the command word. If the question says "State", don't explain. If it says "Explain", don't just state. Use the number of marks as a guide to how many separate points to make.
1 Basic Recall (Low Demand)
State
Short answerWhat it means: Say it clearly and briefly. No explanation needed.
Example Q: State the function of the nucleus.
Good answer: "Controls cell activities" or "Contains genetic material"
Not needed: "The nucleus is important because it controls..." (State does not ask why, so this only uses up time)
Define
What it means: Give the exact meaning of a term. Learn the syllabus definitions and use their key terms.
Example Q: Define osmosis.
Good answer: "The net movement of water molecules through a partially permeable membrane, from a region of higher water potential (a dilute solution) to a region of lower water potential (a concentrated solution)"
Tip: Learn each syllabus definition with all of its key terms
Give
What it means: Produce an answer, either from information you are given (a table, graph or passage) or from memory. No explanation needed.
Example Q: Give two greenhouse gases. [2]
Good answer: "Carbon dioxide and methane"
Identify
What it means: Name, pick out or recognise something, often from a diagram, data or other information you are given.
Example Q: Identify structure X in the diagram.
Good answer: "Mitochondrion"
2 Understanding (Medium Demand)
Describe
Say whatWhat it means: Say what something is like or what happens, covering its key features. Say what, not why.
Example Q: Describe what happens to the chromosomes when a cell divides by mitosis.
Good answer: "Before mitosis, each chromosome is copied exactly. During mitosis the copies separate, so each new nucleus gets the same number of chromosomes. Two genetically identical cells are formed."
Tip: Use sequence words (first, then, finally) for processes
Outline
What it means: Give just the key points, briefly: the main steps or ideas, not every detail.
Example Q: Outline the role of enzymes in digestion.
Good answer: "Enzymes break down large insoluble molecules into small soluble molecules that can be absorbed."
Calculate
What it means: Work out an answer from the facts, figures or information given. Always show your working.
Example Q: Calculate the magnification if the image is 5 mm and the actual size is 0.05 mm.
Good answer: "Magnification = image size ÷ actual size = 5 ÷ 0.05 = ×100"
Tip: Write the formula, show substitution, give the answer with units (if it has any)
Sketch / Construct
What it means: "Sketch" = a simple freehand drawing that shows the key features (in the sciences, keep the proportions roughly right). "Construct" (Mathematics) = draw it accurately, for example with a ruler and compasses.
Tips: Use a sharp pencil. Label clearly. Draw large enough to show detail.
Determine
What it means: Find a value or answer using given data or from a graph/diagram. Often requires calculation or reading from data.
Example Q: Determine the acceleration from the graph.
Good answer: "Gradient = (20-0)/(4-0) = 5 m/s²"
3 Application & Analysis (Higher Demand)
Explain
Say why or howWhat it means: Give reasons or purposes: say why and/or how something happens, make the links between ideas clear, and back them up with relevant evidence. Use "because", "therefore", "so".
Example Q: Explain why the rate of photosynthesis increases as light intensity increases.
Good answer: "Light provides the energy for photosynthesis. At low light intensity, light is the limiting factor, so more light means chlorophyll absorbs more light energy and glucose is made faster."
Bad answer: "Because there is more light" (no mechanism)
Tip: Explain goes beyond describing: say why or how, and link each point to the next.
Compare
What it means: Point out similarities and/or differences between two things. Make each point about both things.
Example Q: Compare arteries and veins.
Good answer: "Arteries have thick muscular walls whereas veins have thin walls. Arteries carry blood away from the heart but veins carry blood towards the heart."
Bad answer: "Arteries have thick walls. Veins have valves." (not comparative)
Tip: Use comparative words: "whereas", "but", "while", "both", "neither"
Deduce
What it means: Reach a conclusion from the information given. Use logic and evidence.
Example Q: The graph shows enzyme activity stops at 70°C. Deduce what has happened.
Good answer: "The enzyme has been denatured because the high temperature has changed the shape of the active site, so the substrate can no longer fit."
Predict
What it means: Say what is likely to happen, based on the information given and what you know.
Example Q: Predict what will happen to the rate of reaction if the temperature is increased.
Good answer: "The rate of reaction will increase."
Tip: If the question also asks you to explain, add the reason: the particles have more kinetic energy, so they collide more often and more of the collisions have enough energy to react.
Suggest
What it means: Apply your knowledge to an unfamiliar situation. There may be more than one correct answer.
Example Q: Suggest why plant A grew taller than plant B.
Good answer: "Plant A may have received more light/water/minerals, or had less competition, or was a different variety."
Tip: "Suggest" often means the answer isn't directly in your notes — think logically!
Justify
What it means: Back up a statement or decision with evidence or a reasoned argument.
Example Q: The temperature of a reaction mixture rises from 20 °C to 32 °C. Justify the statement that the reaction is exothermic.
Good answer: "The temperature rose by 12 °C, which shows thermal energy was transferred to the surroundings, so the reaction is exothermic."
4 Evaluation (Highest Demand)
Evaluate
What it means: Judge how good, important or valuable something is (in some questions, Evaluate means work out an amount or value instead). Weigh up the evidence, consider strengths and weaknesses, and give a conclusion.
Example Q: Evaluate the use of insecticides in farming.
Good answer: "Advantages: kill insect pests, so crop quality and yield improve. Disadvantages: can also kill helpful insects such as pollinators, and can harm other organisms in food chains. Overall: useful for producing more food, but best used only when needed, to limit harm to other species."
Discuss
What it means: Explore the topic in detail, in an organised answer. Where there are arguments on different sides, cover them and finish with a conclusion.
One way to structure it: Point 1 (for) → Point 2 (against) → Point 3 (for) → Conclusion
Analyse
What it means: Break down information into components. Examine relationships and patterns.
Example Q: Analyse the data in Table 1.
Good answer: Quote specific data. Identify trends. Explain anomalies. Link to scientific principles.
Quick Reference Table
| Command Word | What to Do | Key Words to Use |
|---|---|---|
| State / Give | Brief answer, no explanation | — |
| Define | Give the exact meaning | "...is defined as..." |
| Describe | Say what happens (not why) | "First... then... finally..." |
| Calculate | Show working + answer + units | Formula → substitution → answer |
| Determine | Find value from data/graph | Read, measure, calculate |
| Explain | Give reasons why or how | "because...", "therefore...", "so..." |
| Compare | Similarities and/or differences | "whereas", "but", "both", "while" |
| Evaluate | Pros, cons, then judgement | "Advantage...", "However...", "Overall..." |
| Suggest | Apply knowledge to new context | "This could be because..." |
| Justify | Back up a statement with evidence | "This shows that...", "The evidence for this is..." |
Subject Formula Sheets
© LumiExams.com | IGCSE Command Words Guide | Based on the command word tables in Cambridge IGCSE syllabuses
Frequently Asked Questions
What is the difference between Describe and Explain in IGCSE?
Describe means set out the main points or features: what something is like or what happens (the 'what'). Explain means give reasons: say why and/or how something happens, make the links clear and back them up with evidence (the 'why' or 'how'). For example: Describe the trend = 'It increases then decreases'. Explain the trend = 'It increases because... then decreases because...'
What does 'State' mean in IGCSE exams?
State means give the answer clearly and briefly, with no explanation. A short phrase is often enough: 'State the name of the process' needs just the name, not a description of how it works.
How do I answer 'Evaluate' questions in IGCSE?
Evaluate means make a judgement about how good, important or valuable something is; in some questions it means working out an amount or value instead. For a judgement, weigh up the evidence, consider the points for and against, and reach a conclusion you can justify.
What command words are used in IGCSE exams?
Common IGCSE command words include: State, Define, Identify, Give (basic recall); Describe, Outline, Calculate (understanding); Explain, Compare, Suggest, Predict (application); Evaluate, Discuss, Analyse (evaluation). Each requires a different type of response. Each Cambridge IGCSE syllabus lists the command words used in its exams, with their meanings, so check the list for your subject.
Last updated