Students lose marks on questions they understood. It happens constantly in the sciences, and the mechanism is almost always the same: they were asked to explain something and they described it instead.
Command words are not writing style. They are a contract. The word at the front of the question tells you the shape of the answer the mark scheme has been written to accept, and if your answer is the wrong shape the marks are not there to be given, however correct the content is.
Here is what each one is actually asking for.
State, give, name, write down
What it wants: the answer, alone, with nothing attached.
What it does not want: justification, working, or a sentence.
These are the one mark questions and they are the fastest marks on any paper. “State the unit of momentum” wants kg m/s. It does not want a paragraph about how momentum is mass times velocity.
The mistake here is not usually getting it wrong. It is spending ninety seconds writing three sentences for one mark, and then running out of time on a question worth six.
Describe
What it wants: what happens. The observable facts, in order.
What it does not want: why.
If a question says “describe what happens to the rate of reaction as temperature increases”, the answer is that it increases, and increasingly steeply. That is it. That is the mark.
Describe questions on graphs are a whole genre of their own and they are marked on specific features: the direction, the shape, where it changes, and quoted values from the axes. That last one is where the marks go. “The volume goes up then levels off” is one mark. “The volume rises steadily to 40 cm³ by 25 seconds, then levels off” is often two, because it used the data.
The habit: if there is a graph or a table in front of you and the question says describe, quote a number from it.
Explain
What it wants: why. A causal chain, link by link.
What it does not want: a restatement of what happened.
This is the big one, and it is where most avoidable marks are lost in GCSE science.
The mark scheme for an explain question is a chain, and each link is a separate mark:
The rate increases (1) because the particles have more kinetic energy (1) so more collisions have energy above the activation energy (1)
Three marks, three links. A student who writes “the rate increases because the particles move faster” has the first link and half of the second. They understood the chemistry perfectly. They scored one of three, because they jumped from cause to effect without writing the middle.
The habit: when you see “explain”, write the word because or so at least once, and then check that every step of the chain is on the page rather than in your head. If the question is worth 3 marks, you are looking for roughly three links.
Compare
What it wants: both things, in the same sentence, on the same criterion.
What it does not want: a paragraph about A followed by a paragraph about B.
This is the most mechanically failed command word in the set. Comparison marks are almost always awarded for a linked statement. “Arteries have thick walls. Veins have valves” is two facts and frequently zero comparison marks. “Arteries have thicker walls than veins” is one comparative statement and one mark.
The habit: use the word “whereas”, “than”, or “both”, in every sentence.
Suggest
What it wants: a plausible answer you have not been taught.
What it does not want: you to panic because you do not recognise it.
“Suggest” is a signal that this is an application question. The content is not in the specification and the examiner knows it. They are testing whether you can apply something you do know to a context you have not seen.
The mark scheme for a suggest question is usually generous and accepts several different valid lines. Which means the worst possible response is a blank space, and a sensible attempt using the right principles frequently scores.
Calculate and determine
What it wants: the number, plus the working.
Determine is the stricter of the two: it usually implies you have to obtain something from a graph or given data first, rather than plugging into a formula.
Both nearly always carry method marks: the substitution line and the unit are the two most commonly missing marks on the whole paper.
Evaluate, justify, assess, discuss
What it wants: both sides, and then a decision.
What it does not want: a list.
These are the extended answers, and they are marked in levels rather than points, which works differently enough to be worth its own article: how levels marking really works. The thing that lifts an answer into the top band is almost never more content. It is the judgement: a conclusion that follows from what you just wrote, and says which way the evidence falls.
A very large number of otherwise strong answers stop one sentence short of the top band because they laid out the advantages and disadvantages beautifully and then never said which mattered more.
The habit: finish with “overall”, and then commit to something.
The two minute check that catches most of this
Before you start writing, do this:
- Underline the command word.
- Look at the marks available. It tells you how many distinct things to say. Four marks means four creditable points, not one point said at length.
- Check the shape matches. Explain needs a “because”. Compare needs a “than”. Evaluate needs an “overall”.
That is it. It takes seconds and it catches the most expensive error in the paper, which is a right answer in the wrong shape.
One thing worth knowing about the words themselves
Command words are defined by each exam board, and the definitions are published. AQA, Edexcel, OCR and WJEC all put a command word glossary in the specification or in a standalone document, and they are not identical between boards.
They are also not identical between subjects at the same board. “Evaluate” in A-level biology and “evaluate” in GCSE geography are asking for related but different things.
If you are revising seriously, find your board’s list for your subject and read it once. It is a page long and it is the highest return reading in the entire specification.
For the teacher who handed this out
The version of this that changes results is not a poster on the wall. It is marking one class set, counting how many marks went to shape rather than content, and handing the class that number.
Marky records each question part separately with the specific point that was missing, which turns that count into a list rather than an impression: for example, that most of the group dropped the same middle link on 4(b). That is also the raw material for feedback students actually act on. See how a marked paper looks.