IB Command Terms Explained (With Answer Scaffolds)

Every IB exam question starts with a command term, and every command term is a promise about what earns the marks. Students lose marks on command terms all the time, and almost never because they don't know the content. They answer a different question from the one being asked.

Below is what each of the most common terms asks for, in my own words (every subject guide ends with an official glossary of them), the trap I see most with each one, and the scaffolds I teach.

The most common command terms

Term	What it asks for	The trap
State	A short, specific answer: a name, a value, a word or two. No reasons, no working.	Writing a paragraph. Extra explanation earns nothing and costs time.
Define	The exact meaning of the term, precise enough that it couldn't describe anything else.	Giving an example instead of a definition.
Outline	The main points in a few lines, without the detail.	Writing as much as for "describe". Outline is shorter.
Describe	A full, detailed picture of what something is like or what happens.	Explaining why. Describe is what and how, not why.
Explain	The detail plus the reasons or causes behind it: the "why".	Stopping at the first reason.
Compare	The ways two or more things are alike, keeping all of them in view the whole time.	Listing differences. In IB, "compare" means similarities.
Compare and contrast	Both the likenesses and the differences, with the items linked point by point rather than treated one at a time.	Describing item A, then item B, without ever linking them.
Analyse	Take it apart to show the key parts and how they fit together.	Summarising instead of taking it apart.
Suggest	A plausible answer, hypothesis or solution that you can back with reasoning, even if you can't be certain.	Freezing because you "don't know". Suggest wants a sensible, reasoned proposal.
Evaluate	Strengths and limitations weighed against each other, ending in a judgement.	Only listing weaknesses, or never reaching a judgement.
Discuss	A balanced look at several arguments or factors, each with evidence, leading to a clear conclusion of your own.	One-sided answers, or no conclusion.

These are my paraphrases, not the IB's wording. The official definitions are in the glossary at the end of each subject guide, and the lists and wording vary slightly between subjects (Chemistry, for example, has a shorter list than Biology), so check the one for your subject.

Marks tell you the length

Before you write a word, look at the marks. In most IB mark schemes, one mark goes to one distinct, correct point. A 4-mark "explain" needs about four separate points, each with its reason, not one point stretched across four sentences.

A quick check after writing: number your points in the margin. If you have two points for four marks, you're not done. If you have nine points for two marks, you've wasted time that the next question needed.

How examiners actually award those points, including what the M and A marks in maths schemes mean, is in my guide to reading IB mark schemes.

Scaffolds for the hard ones

Define: the rucksack test

A definition names the category, then the feature that makes it different. "A rucksack is a bag made for your back." Apply it every time:

Enzyme: a biological catalyst (category) that speeds up a specific reaction without being used up (difference).

If your answer starts with "for example" or "it's when", it's not a definition yet.

Explain: the because-chain

Students write one reason and stop. Push each reason one link further:

Cause → why that matters → what follows from it → real example.

"Water has a high specific heat capacity (cause), because energy is needed to break the hydrogen bonds between molecules (why). So water temperature changes slowly (what follows), which keeps lakes and the oceans thermally stable for the organisms living in them (example)."

Justify: claim, evidence, reasoning

"Justify" was the weak spot an MYP teacher flagged for one of my students' entire class, and it's the same in the DP. The structure is CER:

Claim: your answer, in one sentence.
Evidence: a specific fact, figure, data point or example.
Reasoning: why that evidence supports the claim.
For longer answers: however (the strongest counterpoint) and a final judgement.

Evaluate: weigh, then judge

Evaluate needs both sides and a verdict. A simple pattern:

One or two strengths, each with why it matters.
One or two limitations, each with why it matters.
A judgement: on balance, how useful, valid or convincing is it, and for what?

In Psychology, evaluate studies against the question you're answering. "Small sample size" can be written about almost any study, so it shows nothing on its own. A limitation that is specific to this question shows understanding.

Discuss: the balanced review

Discuss is evaluate with more range. Several factors or arguments, evidence for each, and a conclusion that actually follows from what you wrote. The most common way to lose marks here is a conclusion that just repeats the introduction.

Biology long answers: draw it

In Biology, a clear, labelled diagram can earn marks quickly when the question allows it. That applies especially to "describe" and "explain" questions about structures and processes. Labels must point unambiguously at the right structure, and "annotate" means a short note, not a single word ("Ribosome: site of translation", not just "ribosome"). My full long-answer method is in how to answer IB Biology Paper 2.

The same logic runs through Paper 1B and Paper 2 in the sciences: see Biology Paper 1B and Chemistry Paper 2 for command terms applied to data and calculations.

A three-question check before you hand in

From my coaching notes, these three questions catch most command-term errors:

Which command term is it? Underline it before you start writing.
Does my answer do exactly that? Definition or example? Describe or explain? Similarities or differences?
Do my points match the marks? Count them.

Practise it

Command terms only stick through practice on real-style questions. In Heptavo, every question shows the mark scheme after you answer, so you can see exactly which points earned the marks. Your own past papers with their mark schemes work just as well. The habit to build is comparing your answer to the scheme point by point.