Quick Answer
In an exam question, outline means give a brief account or summary: state the main points clearly, without detailed development or reasons. Define asks for the precise meaning of a term. Describe asks for a detailed account of what something is or how it happens. Explain adds reasons or causes. So an outline is shorter than a description, and neither asks you why.
What You'll Learn
- Outline = a brief account or summary: the main points, briefly, no reasons.
- Define = the precise meaning of a word, phrase, concept or physical quantity.
- Describe = a detailed account of features, steps or patterns, still without reasons.
- Explain = a detailed account including reasons or causes.
- The marks tell you how many points to make and how far to develop each one.
Define, outline, describe and explain at a glance
These command terms ask for different things, not just different lengths. The definitions below are the IB's, from the glossary of command terms in the DP subject guides. Many exam boards use the words the same way: AQA's list, for example, defines outline as 'set out main characteristics' and describe as 'set out characteristics'.
- State: 'Give a specific name, value or other brief answer without explanation or calculation.' A word, a number or a short phrase.
- Define: 'Give the precise meaning of a word, phrase, concept or physical quantity.' One accurate sentence, ideally in the wording of your syllabus.
- Outline: 'Give a brief account or summary.' The main points, one short sentence each, and nothing more.
- Describe: 'Give a detailed account.' The features, steps or pattern, each developed with specific detail, but with no reasons.
- Explain: 'Give a detailed account including reasons or causes.' What happens and why or how it happens.
Pro Tip
Two questions sort most of these. Does the question want the meaning of a term? Then define. Does it want reasons? Then explain. If neither, decide between outline (brief) and describe (detailed) by the marks.
What outline means in a question
When a question says outline, it wants a short summary of the main points. Think of it as the headlines of a topic: each key point stated clearly and accurately, with just enough detail to be correct, and no development, examples or reasons beyond that. Outline does not mean draw an outline or make a plan. Outline questions are usually short and carry few marks. Some illustrative examples:
- Biology: 'Outline the role of helicase in DNA replication.' Helicase unwinds the double helix and separates the two strands by breaking the hydrogen bonds between complementary bases. Two clear points, then stop.
- Economics: 'Outline two functions of money.' Money acts as a medium of exchange, so goods do not have to be bartered. It also acts as a store of value, so purchasing power can be saved for later. Two functions, one short sentence each.
- History: 'Outline the military terms imposed on Germany by the Treaty of Versailles.' The army was limited to 100,000 men, conscription was banned, Germany was not allowed an air force, the navy was restricted and the Rhineland was demilitarised.
- Psychology or business: 'Outline one limitation of this study' or 'Outline one advantage of this strategy.' Name the limitation or advantage and say in one sentence what it is. The question has not asked you to explain its effect.
Watch Out
Writing more than an outline needs earns nothing extra. Reasons, extended examples and evaluation in an outline answer cost you time you need for the higher-mark questions.
What describe means, and how it differs from outline
Describe asks for a detailed account. You still say what is there or what happens, as in an outline, but you develop each point with specific detail: names, stages, values, features. You do not give reasons. The easiest way to see the outline vs describe difference is to take one topic both ways. Outline DNA replication: the double helix is unwound and the strands separated, each strand acts as a template, and new complementary strands are built, giving two identical molecules. Describe DNA replication: you give the same steps with the detail that makes each one precise, such as helicase breaking the hydrogen bonds, free nucleotides pairing with the exposed bases by complementary base pairing, and DNA polymerase joining them into a new strand. When the question gives you data or a graph, describe means:
- State the overall trend or pattern first.
- Quote specific values with units, including the highest and lowest points.
- Note changes in the rate or direction of change, and where they happen.
- Point out anomalies or exceptions.
- Compare series if there is more than one, using the figures.
- Stop before explaining why. If the question wanted causes, it would say explain or suggest.
Pro Tip
Outline vs describe in one line: an outline names the main points, a description develops each of them. Neither gives reasons.
What define means
Define asks for the precise meaning of a word, phrase, concept or physical quantity. Precision is the whole task: a definition that misses one key word can lose the mark. Learn the definitions in your subject guide's syllabus content and use their wording. A definition is not an example, a description of what the thing does, or a sentence that repeats the word being defined. Illustrative examples of tight definitions:
- Biology, osmosis: the net movement of water molecules across a partially permeable membrane from a region of lower solute concentration to a region of higher solute concentration.
- Economics, opportunity cost: the value of the next best alternative given up when a choice is made.
- Physics, momentum: the product of an object's mass and its velocity.
- A weak version for comparison: 'opportunity cost is when you have to choose between things'. It is vague, has no 'next best alternative' and would usually not earn the mark.
Outline vs explain, and outline and explain
Explain asks for a detailed account including reasons or causes, so it goes further than both outline and describe. Outline says what the main points are. Explain says why or how they happen and links each cause to its effect. If a question says outline one cause of inflation, naming and briefly stating the cause is enough: for example, rising costs of production, such as wages or imported raw materials, pushing up prices. If it says explain how rising production costs can cause inflation, you need the chain of reasoning: higher costs reduce what firms are willing to supply at each price, short-run aggregate supply shifts left, and the price level rises. When a question has two parts, such as outline X and explain Y, answer each part to its own depth: a short summary for the first and a reasoned account for the second.
How much to write: let the marks decide
The command term tells you what kind of answer to give. The mark allocation tells you how much. Short-answer markschemes usually list the creditable points, so these rules of thumb work across most subjects.
- Define, 1 or 2 marks: one precise sentence. A second sentence only if the term has two essential parts.
- Outline, 2 marks: two distinct, correct points, about one sentence each.
- Outline, 3 or 4 marks: three or four distinct points. Brief does not mean fewer points than marks.
- Describe, 3 marks or more: as many developed points as there are marks, each with specific detail or data.
- Check past papers and markschemes for your subject to see how points are credited in practice.
Common mistakes with these command terms
Most lost marks on low-tariff questions come from answering a different command term from the one on the paper.
- Explaining when asked to outline: reasons earn nothing and eat time.
- Outlining when asked to describe: bare points without the detail that carries most of the marks.
- Defining with an example instead of a meaning, or repeating the word in its own definition.
- Dropping a key word from a learned definition, such as net or partially permeable in osmosis.
- Describing a graph without numbers or units, or slipping into causes the question did not ask for.
- Making fewer points than there are marks on an outline question because it says brief.