How long should written feedback be?

For a typical 1500 to 2500 word assignment, two or three targeted comments in the script and a three to five sentence summary is usually enough. More than that tends to bury the points that matter.

Should I correct every spelling and grammar error?

Usually not. Correct the first few examples, name the pattern, and suggest a strategy or support service. Marking every error takes time and hides the more important comments.

What is feed-forward?

Feed-forward is feedback written to help with future work rather than only judging the completed task. It names a habit or technique the student can apply on their next assessment.

Writing feedback students actually act on

Feedback6 min readUpdated 29 September 2026DeepMarking team

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Many students look at the mark, skim the comments, and never open the script again. Often that is a reasonable response to feedback that describes what was wrong with a finished piece of work they will never submit again. This guide covers how to write comments that point to the next task, how specific to be, how long to write, and how to keep the tone useful, with examples of weak comments rewritten.

Feedback versus feed-forward

Most comments look backwards: "Your analysis was superficial." That is an accurate judgement, but the student cannot do anything with it. The essay is gone.

Feed-forward takes the same observation and turns it into an instruction for next time: "In your next essay, after each quote, add a sentence that says what the quote shows about your argument. That is the step that was missing here."

You do not need to abandon backward comments. Students need to understand why they got the mark. But the most useful comment on any script is usually the one that names a transferable habit they can change.

A practical rule: for every script, write at least one comment that would still make sense if the student read it just before starting the next assessment.

Be specific enough to act on

Vague comments are the most common reason feedback goes unused. "Needs more depth", "watch your structure" and "good work" feel like feedback to write but give the student nothing to do.

Specific comments have three parts:

What you saw, with a location if possible.
Why it matters for the criterion.
What to do instead, next time.

You will not always manage all three, but aiming for them keeps comments grounded.

Weak comments rewritten

Weak comment	Rewritten
Needs more critical analysis.	Paragraphs 3 to 5 summarise each study in turn. To reach Distinction, compare them: where do the findings agree, where do they conflict, and which do you find more convincing and why?
Good structure.	Your introduction states the argument and each section heading maps to one step of it. Keep doing this: it made your reasoning easy to follow.
Referencing needs work.	Several paraphrases on pages 2 and 3 have no citation. Every time you use someone else's idea, cite it, even if you have not quoted directly.
Your conclusion is weak.	Your conclusion introduces a new point about funding that is not discussed earlier. Next time, use the conclusion to restate your answer and say what follows from it, rather than adding new material.
Unclear.	I could not tell whether "this" in the second sentence refers to the policy or the outcome. Naming the thing directly ("this policy") would fix it.
Well done!	This is a strong report. The clearest improvement would be in the discussion: link each limitation you list to how it might affect your results.
Poor code quality.	Your `process_orders` function is 140 lines and does three separate jobs. Split it into smaller functions with descriptive names; it will also make testing each part easier.
Needs to engage with the question.	The question asks you to evaluate the policy, but most of the essay describes how it works. Spend at least half your word count on whether it achieved its aims and what the evidence says.

How much to write

More feedback is not better feedback. A script covered in thirty marginal notes buries the two comments that matter. Students generally cannot act on more than a few points at once.

A structure that works for most written assessments:

Two or three targeted comments in the script, placed at the point where the issue appears.
A summary of three to five sentences at the end: one sentence on the main strength, one or two on the main thing to improve with a concrete next step, and one on the mark if the rubric does not make it obvious.

For a 2000 word essay that is around 100 to 180 words in total. For a short weekly task, one well chosen sentence is often enough.

Resist correcting every typo. If spelling or grammar is a real problem, correct the first two or three examples, name the pattern, and point to support: "I've marked three spelling errors on page 1; there are more of the same kind throughout. A read-aloud check before submitting would catch most of them."

Tone

Students read tone as closely as they read content, and harsh comments tend to be remembered long after the advice is forgotten.

Some guidelines that hold up:

Comment on the work, not the person. "This paragraph does not support its claim" rather than "you have not understood".
Be direct about problems. Softening a real issue until it disappears is not kind. "There is a significant problem with your method" is fine if it is followed by what the problem is.
Avoid sarcasm and rhetorical questions. "Did you read the brief?" might be satisfying to write. It gives the student nothing.
Mean the praise. Generic praise at the start of every comment ("Great effort!") teaches students to skip it. Specific praise tells them what to keep doing.
Watch for patterns. If you find yourself writing sharper comments late in a marking session, take a break.

The "feedback sandwich" of praise, criticism, praise is widely used, but students often learn to skip the bread. It is usually clearer to state the main strength and the main improvement plainly, in that order.

Link comments to the rubric

Where the assessment uses a rubric, name the criterion in your comments. "For Use of evidence, you are at Credit: each claim has a source. To move up, explain why the source supports the claim, not just that it does." This helps the student read the rubric as a map, and it helps markers stay consistent because comments and levels line up.

Make it easy to act on

Even well written feedback goes unused if students never engage with it. A few practices help:

Release comments before the mark. Some units release comments a day or two ahead, or ask students to read feedback and write one sentence on what they will change before seeing their grade.
Ask for a feedback response on the next task. A short cover note ("In this essay I worked on linking evidence to claims, as suggested in Assessment 1") prompts students to reopen old comments and lets you check whether they did.
Time it. Feedback that arrives after the next task is due is mostly wasted. If turnaround is tight, a short, fast comment is worth more than a detailed one that comes too late.

A complete example

Here is a summary comment on a second year sociology essay marked at 64 (Credit):

It is 90 words, names one strength, one main improvement with a concrete method, links to two criteria, and closes with a small but real positive. A student can read it in thirty seconds and know what to try next time.

Common questions

How long should written feedback be?: For a typical 1500 to 2500 word assignment, two or three targeted comments in the script and a three to five sentence summary is usually enough. More than that tends to bury the points that matter.
Should I correct every spelling and grammar error?: Usually not. Correct the first few examples, name the pattern, and suggest a strategy or support service. Marking every error takes time and hides the more important comments.
What is feed-forward?: Feed-forward is feedback written to help with future work rather than only judging the completed task. It names a habit or technique the student can apply on their next assessment.

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