Why you keep losing marks in GCSE exams (and how to find out which reason it is)

My daughter is just starting GCSEs, so I've been reading ahead on the question every parent eventually asks: how does a child who clearly knows the material still come out of a mock with a grade that makes no sense? Go through what examiners actually say in their reports and the answer usually isn't one big gap. It's the same handful of small leaks, repeated on question after question — and they turn out to be everyone's leaks. The boards flag the same patterns every single year.

Here's the short version: most GCSE marks are lost to technique, not knowledge. The content is usually in the student's head — it just doesn't reach the paper in the form the mark scheme pays for. The good news is that technique problems are diagnosable and fixable, often much faster than learning new content. This guide is the diagnostic: six patterns, what each one looks like, and — because I've written a separate deep-dive guide on each fix — where to go next.

First, how to run the diagnosis

You need a marked paper — a mock is perfect (if mocks are new territory, I've written a plain-English guide to GCSE mocks). Sit down with your child and go through it question by question, sorting every lost mark into one of the piles below. Don't argue about any individual question; you're looking for the pattern. In my experience one or two piles dominate, and that tells you exactly what to work on.

Pattern 1: Answering a question that wasn't asked

The symptom: the answer is good — sometimes genuinely impressive — but it's about the wrong thing. Marks lost with comments like "not answering the question" or nothing credited at all despite a full page of writing.

This one has two flavours. The first is autopilot: the student sees a familiar topic — osmosis, Macbeth's ambition, resistance in circuits — and starts writing what they revised before they've finished reading what's actually being asked. Examiners know students do this, and they deliberately vary the angle on familiar topics. The second flavour is missing the small words: not, only, between, a date range, "in Source B" — one skipped word and the whole answer is aimed at a different target.

The fix: read the question twice, underline the command word and the focus, and only then write. It sounds too simple to matter. It isn't — it's the single cheapest habit in this whole guide.

Pattern 2: Describing when the question says explain

The symptom: answers that say what happens but never why, marked with "describes only" or stuck in the bottom band of a levels grid.

Every command word is an instruction about what kind of answer earns the marks. Describe wants what happens; explain wants why, with a because-chain; evaluate wants a judgement, not a list. Examiner reports across the boards say the same thing every series: students lose marks because their answer doesn't match the verb, even when the content is right. A brilliant description of a question that asked for an explanation gets partial credit at best.

The fix: learn what each verb is actually asking for. This is exactly what my GCSE command words guide covers, word by word — it's the natural next stop if this pile is the big one.

Pattern 3: Writing the wrong amount

The symptom: two flavours again, and they often show up in the same student. Half a page written for a 1-mark "state" question — time and effort the mark scheme cannot pay for, because a "state one way" question credits exactly one way and ignores everything after it. And then three thin lines for the 6-marker at the end, which is marked on levels and needs developed, linked points to climb the grid.

The mark allocation printed next to every question is the exam paper telling your child how much an answer is worth — and most students never read it.

The fix: match effort to marks. For the small ones — state, give, identify, define — short is safe. For the big ones, the 6-mark question guide shows what a levels-marked answer needs that a list of facts doesn't.

Pattern 4: The invisible working

The symptom: maths and science papers where the answer line is filled in but the space above it is blank — and a single slip somewhere means the whole question scores zero.

On multi-step calculation questions, most of the available marks are usually for the method, not the final number. A student who shows every step can drop the final answer and still collect most of the marks; a student who does it all on the calculator and writes one number is betting everything on that number being perfect. Examiner reports across AQA, Edexcel and OCR cite missing working as one of the most consistent sources of lost marks in maths. Its close cousin is rounding too early — rounding a value mid-calculation, so the error compounds and the final answer misses the mark scheme's range even though the method was right. Keep full values in the calculator; round once, at the end.

And one more that surprised me: on AQA science papers, a correct statement can be cancelled out by a contradicting wrong one in the same answer — and if the contradictions match or exceed the marks available, the answer scores nothing. "Write everything and hope" isn't just inefficient. It can actively delete marks your child had already earned.

The fix: show every step, round last, and never scattergun. My guide to how GCSE mark schemes actually work unpacks method marks, levels grids and the contradiction rule properly.

Pattern 5: One-sided answers to two-sided questions

The symptom: compare questions answered by writing everything about one thing, then everything about the other — or worse, only one of them. Evaluate questions answered with a list of points for, and no against, and no judgement at the end.

Mark schemes are strict about this. On compare questions, an answer that only covers one side typically caps at one or two marks no matter how good it is — the marks are awarded for the comparisons, made with comparative language. Evaluate questions expect both sides and a conclusion that actually commits to a view.

The fix: structure that forces both sides onto the page — that is what a compare question is really asking for, and the evaluate questions guide shows the same discipline for evaluate. And if your child leans hard on PEEL paragraphs for everything, it's worth knowing AQA's own examiner reports warn that rigid structures can hold the best answers back.

Pattern 6: Running out of time

The symptom: the last questions blank or rushed — which is expensive, because the questions at the end of most papers are the big-mark ones. Ten careful minutes polishing a 2-mark answer at the start of the paper is ten minutes stolen from a 6- or 9-marker at the end.

The fix: time by marks, not by feel. A rough rule that works across most GCSE papers: about a minute per mark, with a few minutes held back for checking. A 4-mark question gets four-ish minutes; when they're up, move on and come back. This is a habit built in timed past-paper practice — it doesn't appear on exam day by itself.

What to do with the diagnosis

Count the piles. If "didn't know it" dominates, this is genuinely a revision problem — go back to the content. But if the marks are leaking through any of the six patterns above, more revision won't fix it, because the problem was never knowledge. Pick the biggest pile, read the guide that owns that fix, and practise it on past-paper questions with the mark scheme open. Technique errors repeat on every paper your child sits — which is exactly why fixing one recovers marks everywhere at once.

That mock that made no sense to us? Her piles were patterns 2 and 6. Two fixes, a few weeks of practice, and the next set of papers looked like a different student had sat them. Same knowledge. Better delivery.

Related guides

• GCSE command words: what exam questions are really asking
• GCSE mark schemes explained
• How to answer 6-mark questions
• How to answer evaluate questions
• GCSE mocks explained

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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.