KS2 Writing Best-Fit Judgements: How AI Can Support Borderline Decisions

KS2 writing teacher assessment is an important statutory responsibility, but it can also be one of the more time-consuming aspects of assessment in Year 6. Teachers need to consider evidence across a pupil’s writing, apply the statutory framework accurately and make professional judgements where attainment is not completely clear-cut.

This is particularly challenging when a pupil appears to sit on the boundary between working towards the expected standard (WTS), working at the expected standard (EXS) or working at greater depth (GDS).

A rounded approach to assessment, supported by effective moderation and appropriate use of AI assessment tools, can make this process more manageable. Rather than replacing professional judgement, technology can help teachers review evidence more quickly, identify areas that deserve closer attention and provide a useful second opinion when judgements are less straightforward.

For a broader introduction to the statutory expectations, see our guide to understanding the DfE writing assessment framework for KS1 and KS2.

Understanding Statutory KS2 Writing Assessment Requirements

At the end of Key Stage 2, schools in England must make a statutory teacher assessment judgement for writing.

The Key Stage 2 teacher assessment guidance published by the Standards and Testing Agency sets out how schools should make and moderate these judgements.

For pupils working within the KS2 framework, there are three standards:

• working towards the expected standard (WTS)
• working at the expected standard (EXS)
• working at greater depth within the expected standard (GDS)

The full requirements are set out in the government's teacher assessment frameworks at the end of Key Stage 2.

Teachers assess pupils against the relevant ‘pupil can’ statements using evidence from writing produced independently.

Unlike a test taken on a single day, writing assessment draws on what a pupil can demonstrate through their classroom work over time. This inevitably requires a degree of professional judgement.

The statutory guidance recognises this and gives teachers flexibility to reach a rounded judgement about a pupil’s overall attainment.

What Does ‘Best-Fit’ Mean in Practice?

The phrase ‘best-fit’ is often used informally when discussing writing assessment. In practice, however, this should not mean simply deciding which standard a pupil appears closest to.

Teachers must still assess the pupil against all of the ‘pupil can’ statements within the standard at which they are being judged.

The important distinction is that writing is not assessed as though every statement were simply a box that must appear an identical number of times.

A pupil may demonstrate some skills frequently and others only where the purpose and form of the writing make them appropriate. For example, evidence of consistent verb tense might reasonably appear across almost every piece of writing, whereas integrating dialogue to develop character will naturally only be relevant to certain forms of narrative writing.

Teachers therefore consider the evidence as a whole and ask:

Does this collection of writing convincingly demonstrate that the pupil is working at this standard?

This is where professional judgement becomes essential.

The statutory guidance also allows teachers to exercise discretion where a pupil has a particular weakness. If there is good reason to believe that one weakness is an exception to an otherwise secure standard of writing, that weakness does not necessarily have to prevent the pupil from being judged at that standard.

For more on applying the framework in day-to-day assessment, see how to use the DfE writing framework to improve KS2 writing assessment.

Why KS2 Writing Assessment Is Not Just a Checklist

Assessment frameworks are useful because they provide common expectations. But using them too mechanically can make assessment unnecessarily difficult.

Imagine a pupil whose writing consistently demonstrates strong composition, appropriate vocabulary, accurate sentence construction and secure punctuation. One particular aspect of spelling, however, remains noticeably weaker.

A checklist approach might encourage the teacher to focus almost entirely on the missing evidence.

A rounded assessment asks a different question:

Is this weakness representative of the pupil’s overall standard of writing, or is it a particular weakness within an otherwise convincing body of evidence?

This does not mean ignoring framework statements. Teachers still need evidence against the standard being awarded.

Instead, it recognises that writing is complex. Pupils rarely demonstrate every aspect of writing with exactly the same level of consistency.

The distinction becomes particularly important for pupils close to assessment boundaries.

What If the Evidence Is Inconsistent?

Inconsistent writing is common.

A pupil might produce an excellent narrative but a much weaker explanation text. They might punctuate accurately in several pieces but make noticeably more errors when attempting more complex sentence structures. Another pupil may demonstrate features associated with greater depth occasionally without sustaining them across their writing.

When this happens, avoid allowing one unusually strong or weak piece to dominate the judgement.

Instead, consider:

• whether the skill appears across different pieces and purposes
• how frequently and independently it is demonstrated
• whether weaker evidence is typical or exceptional
• whether the pupil has demonstrated the relevant skill in more recent writing
• whether the collection provides sufficient breadth to support the overall judgement

The aim is to identify the standard that most accurately represents what the pupil can demonstrate independently across their writing.

The DfE's KS2 English writing exemplification materials can be particularly useful where teachers want to compare their judgement with examples of writing that have been assessed against national standards.

Borderline WTS, EXS and GDS Judgements

Borderline decisions are often where assessment takes the most time.

Consider these simplified examples.

Borderline WTS to EXS

A pupil writes clearly for different purposes and generally controls tense well. Their vocabulary is appropriate and their writing is coherent. However, aspects of the expected-standard statements remain inconsistent across several pieces.

The question is not simply whether an example of a particular skill can be found somewhere in the pupil’s books.

Teachers need to consider whether the collection as a whole provides convincing evidence that the relevant expected-standard statements have been met.

If several important aspects remain insecure, WTS may still be the most accurate judgement.

Borderline EXS to GDS

Another pupil writes confidently across several genres. Their writing is technically accurate, vocabulary is well chosen and they adapt their style effectively for different audiences.

Occasionally, however, they produce sophisticated features associated with greater depth only when the task strongly encourages them.

Here, the teacher needs to consider whether those features represent the pupil’s normal independent writing or isolated examples of stronger performance.

Greater depth should reflect a convincing body of evidence, rather than a handful of impressive sentences.

A Particular Weakness

A third pupil demonstrates the expected standard convincingly across their writing but has one identifiable weakness that is noticeably less secure.

If the teacher has good reason to judge that this is an exception to the pupil’s overall attainment, the statutory guidance allows professional judgement to take precedence over requiring perfect performance against every aspect of the framework.

Crucially, the teacher should be able to explain and evidence that decision during moderation.

These examples are deliberately simplified. Actual judgements should always be made using the statutory framework, supporting guidance and the pupil’s own body of independent writing.

Use Evidence Across Several Pieces of Writing

One way to make assessment more reliable is to avoid asking individual pieces of writing to prove too much.

Different tasks naturally provide different opportunities.

A narrative may provide particularly useful evidence of characterisation, dialogue and cohesion. A persuasive letter might reveal how effectively a pupil selects vocabulary for audience and purpose. Writing completed elsewhere in the curriculum can provide further evidence of how independently and consistently skills are applied.

Looking across several pieces gives teachers a much clearer picture than repeatedly searching one piece for every possible assessment statement.

It can also make borderline decisions easier.

If a feature appears securely across different contexts, confidence in the judgement increases. If it appears once and then disappears from subsequent writing, further evidence may be needed.

The DfE's KS2 teacher assessment guidance makes clear that teacher assessment should draw on a broad range of evidence and knowledge of how a pupil has performed over time and in different contexts.

Moderation Should Be a Professional Conversation

Moderation plays an important role in maintaining consistent writing assessment.

But productive moderation is more than two teachers comparing highlighted checklists.

The most useful conversations often centre on the reasoning behind a judgement:

Which evidence makes you confident this pupil is EXS?

Is this weakness typical of their writing?

Does this feature appear independently elsewhere?

Is the evidence sufficiently consistent for GDS?

Discussing the evidence in this way helps teachers develop a shared understanding of the standards and can increase confidence when making future judgements.

The same principle applies during statutory external moderation. Where a teacher has applied the ‘particular weakness’ provision, they should be prepared to explain why the awarded standard remains the most accurate description of the pupil’s overall attainment.

The Standards and Testing Agency describes external moderation as a collaborative process designed to validate teacher assessment judgements and ensure they are consistent with national standards. Schools can find further information in the official KS2 teacher assessment and moderation resources.

Where AI Writing Assessment Can Help

AI assessment tools can provide useful support during this process.

A tool such as WriteAssess can analyse a piece of pupil writing against relevant assessment criteria and quickly highlight strengths, possible gaps and areas that warrant closer inspection.

This can be particularly useful when:

• a teacher wants a second opinion on a borderline judgement
• several pieces need to be reviewed before moderation
• teachers want to compare their interpretation of evidence
• a subject leader wants to identify patterns across a class or cohort
• an assessment does not immediately match the teacher’s initial impression

Rather than starting every assessment from scratch, the teacher has an additional analysis to consider.

This has the potential to reduce some of the repetitive work involved in assessment while allowing teachers to spend more time on the aspects that genuinely require professional judgement.

We've explored this in more detail in how AI writing assessment can support DfE writing standards in KS2.

For schools particularly concerned about marking and assessment time, you can also read our guide to how AI writing tools can reduce teacher workload in KS1 and KS2.

AI Should Be a Second Opinion, Not the Final Judgement

AI assessment has important limits.

It does not have the teacher’s wider knowledge of the pupil. It may be analysing only one writing sample from a much broader collection. It cannot determine every aspect of the conditions under which that piece was produced, and an automated judgement should never override stronger classroom evidence.

There is also an important distinction between using AI to assess completed independent writing and allowing AI to help a pupil produce or edit the writing itself.

The statutory guidance on independent writing states that writing produced using AI, or edited or rewritten following feedback from large language models, should not be used as independent evidence for statutory teacher assessment.

For that reason, AI assessment tools should support the teacher, not write or improve the pupil’s assessed work.

The final judgement remains with the teacher.

This is not simply a safeguard against technology. Professional judgement is an intentional part of KS2 writing assessment because writing cannot always be reduced to a completely mechanical set of rules.

A More Efficient Approach to KS2 Writing Assessment

Reducing assessment workload does not have to mean reducing the quality of assessment.

A more efficient process is to gather a suitable range of independent writing, use the statutory framework to identify the standard supported by the evidence, investigate genuine areas of uncertainty and use moderation where professional discussion would help.

AI can add another useful layer to that process by quickly analysing writing and drawing attention to evidence teachers may want to examine.

The result is not automated teacher assessment.

It is teacher assessment with better support.

By combining evidence across pupils’ writing, a rounded understanding of the statutory framework, professional moderation and carefully used AI tools, schools can make KS2 writing judgements that are both manageable for teachers and grounded in the evidence pupils actually produce.

WriteAssess helps primary school teachers assess pupils’ writing in seconds using AI, with assessments grounded in official DfE writing criteria and exemplification.

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