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ChatGPT Prompt for Selective Writing Feedback

Written by Hao, a Sydney data analyst and parent of a 2025 NSW Selective student. Tested and last updated 1 November 2026.

Ask ChatGPT plainly to mark your child's writing and it gives a mark out of 10, opens with "This is a strong start…" and sometimes rewrites whole paragraphs. The prompt below makes it mark six areas out of 25, quote your child's own sentences as evidence and suggest changes one sentence at a time. We ran both 50 times in total on the model behind ChatGPT. One warning up front: the prompt fixes the feedback, not the mark. On the 8 published NSW samples, ChatGPT's totals came out about 3 marks below the official marks either way.

The Prompt

You are an experienced marker for the NSW Selective High School Placement Test writing task. Mark the piece of writing below. It was written by a Year 5 or 6 student.

Task: [paste the task or topic here]

Writing: [paste the writing here]

Give a mark for each of these six areas (25 in total):
- Content & Detail: 0-5
- Structure & Cohesion: 0-5
- Style & Vocabulary: 0-5
- Sentence Variety: 0-4
- Punctuation: 0-3
- Spelling: 0-3

Rules:
1. First, say whether the writing answers the task and uses the form the task asks for.
2. For every area: give the mark, quote one sentence from the writing as evidence, and say why.
3. For every area, pick one sentence to improve and show a better version. Change single sentences only. Do not rewrite a paragraph or the whole piece.
4. Do not praise anything you cannot back with a quote. Do not invent anything that is not in the writing.
5. End with the total out of 25, then the three most important things to fix, in order of importance.

How to use it well:

1. Your child writes first, on their own. The real test is typed, 30 minutes, unaided. Practise the same way, then paste.
2. Paste the task wording, not just a title. Without it, ChatGPT can't tell whether the piece answers the question or uses the right form (an advice sheet, a diary entry, a story).
3. Start a new chat for each piece, so feedback on an earlier essay doesn't colour the next one.
4. Read the quoted sentences together, not the total. Pick one or two of the suggested changes, and have your child rewrite those sentences in their own words.

Add One Line for the Type of Writing

More on what each form needs is in our guides to narrative, persuasive and informative writing.

What Happened When We Tested It

We used the persuasive opening shown on our homepage: 142 words in two paragraphs, on whether friendship is the most important thing in life. The plain question was "Can you mark my child's writing and tell them how to improve it?". Each version was asked six times, each time in a fresh conversation.

In the ChatGPT app itself (one run each, same day), the plain question went further: after 7.5/10 and "Your child has made a really good start", it added "a corrected version" of the whole piece. The prompt gave 14/25, with the six marks, a quote for each and single-sentence changes, the same as in our test runs.

Does it actually read the sentences? We deleted all five commas from the same piece and ran the prompt six more times. Punctuation dropped from 2 to 1 in all six replies, and the total to 13 every time (from 14 or 15). Nothing else in the piece changed, so the drop came from the commas.

How we tested: OpenAI's chat-latest model through the API, which OpenAI describes as pointing to the latest model used in ChatGPT; default settings; no custom instructions; tested 1 November 2026; 50 runs in all (18 on the homepage piece, 32 on the NSW samples below). For the homepage piece the task line was "Is friendship the most important thing in life? Write a persuasive piece."; for the NSW samples it said only "Write an advice sheet." The ChatGPT app adds its own instructions and memory, and OpenAI updates the model without notice, so your replies will be worded differently. Check the first reply follows the rules.

Can ChatGPT Mark Selective Writing Accurately?

NSW has published 8 marked sample responses to one Selective writing task (an advice sheet), with official totals from 19 to 25 out of 25. We gave each one to ChatGPT twice in two ways: a plain "Can you mark my child's NSW Selective writing out of 25 and tell them how to improve it?", and the prompt above.

Two things stand out. First, ChatGPT squeezes the scale. The official marks for the best and weakest samples are 6 apart (25 and 19); ChatGPT's averages for those two were 1.5 apart with the plain question and 3.5 apart with the prompt. That pattern is common in AI marking, and better wording didn't fix it here: the prompt changed the shape of the feedback far more than the marks. Second, the plain "out of 25" question made up its own marking areas, so its 20/25 isn't measured against the Selective criteria at all.

So read ChatGPT's total as a rough signal, and spend the time on the quoted sentences, which is where the prompt does help. These samples are all strong pieces; we don't have official marks for weaker writing to test against.

For comparison, our own scorer lands within 0.9 marks of the official totals on average on the same 8 samples. In fairness to ChatGPT, our scorer was refined against these samples over many versions, so that is not a blind test. The accuracy page has the method, an independent NSW teacher's check on 23 real essays, and the limits.

Why the Prompt Is Written This Way

• "Year 5 or 6 student" and the task: asked plainly, ChatGPT had to guess the year level (one reply: "I'm assuming your child is in Years 4–6 (ages 9–11)") and had no task to check the writing against.
• The six areas and their marks: without them, it made up its own areas, and they varied from reply to reply. The 25-mark total and its split into a 15-mark set and a 10-mark set follow the published structure of the test; the six areas inside those are our reading of it. Our marking criteria guide explains each area.
• A quote for every mark: you can check each claim against the writing yourself, and vague praise has nowhere to hide.
• Single sentences only: the child should do the rewriting. An AI-written paragraph teaches very little and can't be used in the test.
• No praise without a quote: this is what stops the "This is a strong start…" opening.
• Three things to fix, in order: a list of fifteen suggestions gets ignored. One clear next step gets done.

Before You Start: Age and Privacy

• Age: OpenAI says ChatGPT is not meant for children under 13, and children aged 13 to 17 need a parent's permission. Most Year 5 and 6 students are 10 to 12. Run the prompt yourself and go through the feedback with your child.
• NSW public schools: students in Years 5 to 12 can use NSWEduChat, the Department of Education's own AI tool, through school. We haven't tested this prompt in it.
• Privacy: don't paste your child's full name, school, or personal details from the writing. Check ChatGPT's data controls if you don't want chats used to train its models.
• Other chatbots: the prompt is plain instructions and can be pasted anywhere, but we have only tested it on ChatGPT's model. Check that the first reply gives six marks, quotes the writing and changes only single sentences.

For the bigger picture on where AI helps with Selective preparation and where it doesn't, see why writing is the Selective component best suited to AI practice.

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