How to answer GCSE 'compare' questions: what examiners actually want

Picture a science mock coming back with a big red line through a paragraph a student has clearly worked hard on. Ask what the question was: "Compare the two." They'd written a full, accurate description of the first thing, then a full, accurate description of the second — and scored almost nothing. Not because anything was wrong, but because they'd never actually put the two side by side. "Compare" is one of the most misread words on the whole paper, and the fix is small and teachable. Here's the plain version, parent to parent.

The one-sentence answer

A compare question asks your child to show how two things are similar and how they are different — set directly against each other, using comparative language — and it does not ask for a judgement about which is better. Describing each thing separately, however beautifully, is the classic way to lose the marks.

What the question is actually testing

The exam boards take their command words from a shared official list, and AQA's own definition of compare is telling: it asks students to describe the similarities and/or differences between things, not just write about one. That last clause is the whole game. The skill being tested isn't "do you know about thing A and thing B" — it's "can you hold them up against each other and see the relationship."

So the marks live in the comparison itself, not in the two descriptions. A student can know both topics perfectly and still score badly if the answer reads as two separate mini-essays glued together. The examiner is scanning for moments where the two things meet — and if those moments aren't on the page, there's nothing to reward.

The catch: you usually need both sides

Here's the bit that trips up the most students. On the extended compare questions — the ones worth real marks, especially in science — the mark scheme typically wants both similarities and differences, and often splits the marks between them. Write a brilliant list of ten differences and nothing else, and you'll still hit a ceiling. The same is true in reverse: all similarities, no differences, capped.

I want to be honest about a nuance here, because getting this slightly wrong is worse than not knowing it. AQA's official wording is "and/or" — which means not every compare question demands both. A short geography question that says "compare the values shown in Figure 3" may just want the numbers held against each other. An AQA history question that asks "in what ways are they similar?" is pointing you at similarity specifically. So the real rule is: give both by default, unless the question clearly asks for one. For most extended science compares, both is the safe answer. When in doubt, both.

The trick that turns two descriptions into a comparison

This is the single most useful habit, and it's almost mechanical. Every sentence in a compare answer should contain a comparative connective — a word that links the two things:

• For differences: whereas, however, in comparison, on the other hand, unlike.
• For similarities: both, similarly, also, like.
• And comparative adjectives everywhere: faster, larger, fewer, more reactive, higher.

Take a real science example. Asked to compare mitosis and meiosis, a weak answer describes each in a paragraph. A strong answer says: "Both are forms of cell division that produce daughter cells. However, mitosis produces two identical cells whereas meiosis produces four genetically unique ones; mitosis involves one division, whereas meiosis involves two." Same facts — but now every sentence is doing the comparing, and each linked point is a mark the scheme can award.

That's the second failure mode dealt with, too. Mark schemes generally give one mark per developed comparison, not per fact mentioned. "Take each point in turn and link it across both things" is the instruction that turns knowledge into marks.

Compare vs evaluate — the mix-up that quietly costs marks

Compare and evaluate get confused constantly, and they're marked very differently. An evaluate question wants your child to weigh evidence on both sides and then land on a judgement — a conclusion is compulsory. A compare question wants the side-by-side analysis but no verdict at all. Adding "so overall, mitosis is better" to a compare answer earns nothing and eats time your child doesn't have.

The quick test: does the question ask you to decide something? "Evaluate", "assess", "to what extent", "how far do you agree" all want a judgement. "Compare" just wants the relationship laid out. If you're not sure which word you're dealing with, our GCSE command words guide has the full glossary, and the mark schemes guide explains how the marks are actually counted underneath.

What compare looks like across subjects

Science is where compare does the most damage, because it comes up so often — comparing two reactions, two graphs, two organisms, aerobic vs anaerobic respiration, transition metals vs Group 1. These reward both sides and lean hard on comparative language. A common exam wording asks you to compare two things "using your own knowledge", worth anywhere from 2 to 6 marks.

History treats similarity and difference as a core historical skill in its own right. A typical AQA compare question asks students to compare two periods — "compare hospitals in the nineteenth century with those in the twentieth" — and to explain with specific reference to both. These are extended, several-mark questions, often similarity-led, and they need concrete historical detail from each period, not vague generalisation. No judgement required — that's a different question type.

Geography compare questions are frequently short and data-driven: compare two features on a map, two bars on a graph, two figures. Here the win is using actual values and comparative terms — "the first is roughly double the second" beats "they are different."

How to practise it in ten minutes

• Find three past-paper compare questions in your child's subject and read the mark schemes beside them. The pattern — how many marks, split how between similarity and difference — becomes obvious fast.
• Highlight the connectives in a model answer. If a sentence has no comparative word in it, it probably isn't earning a comparison mark.
• Do the "one sentence, two things" drill. Every sentence must mention both things being compared. It feels stilted at first and then becomes second nature.
• Check the command word twice. Compare, not evaluate. No judgement.

None of this is about knowing more content. It's about knowing what the word is asking for — which is exactly the kind of gap that makes a confident, well-prepared child lose marks they should have had.

A note on exam boards

I've used AQA examples because it's the most common board in England, but Edexcel, OCR and Eduqas run compare questions with the same basic demand — both sides where the question allows it, comparative language, no judgement. The exact mark allocations and question styles vary by subject and board, so the surest move is to pull two past-paper compare questions for your child's actual subject and board and read the mark schemes. That fifteen minutes teaches the skill better than any guide can.

Related guides

• GCSE command words: what 'describe', 'explain' and 'evaluate' actually want
• How to answer GCSE 'evaluate' questions
• GCSE mark schemes explained: how examiners actually award marks

Not sure whether this is the problem costing your child marks? Start with the diagnostic: why you keep losing marks in GCSE exams.

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I'm building Lightbulb Learning for my own daughter — revision that turns the day's actual class topic into a clear evening session, matched to her exam board and year. If that sounds useful for your child, you can join the early list below and I'll let you know the moment it opens.