OET Writing Guide
OET Writing Criteria: All 6 Explained
OET writing is assessed against 6 official criteria developed in partnership with Cambridge Boxhill (the joint venture that runs OET). Understanding each criterion is the first step to reaching Grade B (350+).
In short
- OET Writing is marked on 6 criteria, each scored 0–14, combined and scaled to 500; Grade B needs 350+.
- Under the 2026 rubric, Purpose and clinical relevance of Content are applied more strictly — strong grammar alone no longer reaches Grade B.
- Most candidates lose Grade B on Content selection and Purpose, not on Language.
350+
out of 500
Score required for Grade B
6
all equally important
Assessment criteria
0–14
combined & scaled to 500
Scale per criterion
The 6 OET Writing Assessment Criteria
Each criterion assesses a different dimension of your letter. Strong performance across all six is required for Grade B.
Purpose
Score 0–3Does the letter achieve its communicative purpose?
This criterion asks whether your letter does what it is supposed to do. The examiner checks whether the purpose is immediately clear, whether the letter is addressed to the right person, and whether the overall tone and structure serve the reader's needs. A letter that confuses the recipient about its purpose will score poorly here regardless of grammar quality.
Key tips
- State the purpose in your opening sentence
- Confirm who you are writing to and why
- Close with a specific action or request for the reader
Content
Score 0–7Have you selected the right information from the case notes?
This is the most technically demanding criterion for many candidates. You must select only the case note information relevant to the specific reader and purpose — omitting irrelevant details, expanding on what matters, and never fabricating information not in the notes. Including too much (listing every case note item) and too little (missing critical history) both reduce your score.
Key tips
- Ask: does this piece of information help THIS reader?
- Expand clinical acronyms and summarise where appropriate
- Never invent details not present in the case notes
Conciseness & Clarity
Score 0–7Is the letter focused without losing essential information?
Examiners assess whether you communicate clearly and without unnecessary repetition. Long, rambling sentences reduce your score even if grammatically correct. A 180-word letter that covers everything relevantly scores higher than a 300-word letter that repeats itself or includes irrelevant detail.
Key tips
- Aim for 180–200 words — neither too short nor too long
- Avoid repeating information across paragraphs
- Use active voice and direct phrasing where clinically appropriate
Genre & Style
Score 0–7Does the letter read as genuine professional clinical correspondence?
OET letters are professional documents, not academic essays or personal letters. This criterion assesses whether your letter sounds like authentic clinical correspondence between healthcare professionals. The tone should be formal but not stuffy, specific to the professional register of the healthcare sector, and free of conversational phrasing.
Key tips
- Use professional healthcare register throughout
- Avoid casual language ('the patient is feeling better')
- Match formality level to the recipient's profession
Organisation & Layout
Score 0–7Is information structured logically with clear paragraphing?
Information in OET letters should flow in a logical clinical sequence: purpose → relevant background → current situation → required action. Each paragraph should address one topic. Examiners check whether transitions between paragraphs are smooth and whether the letter layout matches professional letter conventions.
Key tips
- Use clear paragraph breaks between topics
- Follow the logical sequence: purpose → background → current → action
- Include a salutation and closing appropriate to the letter type
Language
Score 0–7Is grammar, vocabulary, and punctuation accurate throughout?
Language is assessed across grammar, vocabulary range, spelling, and punctuation. Errors that impede understanding are penalised most heavily. Consistent minor errors (e.g., article omissions or preposition misuse) reduce your score even if meaning remains clear. A wide range of accurate medical and professional vocabulary improves your score.
Key tips
- Review your use of articles (a/an/the) — a common error area
- Vary vocabulary — avoid repeating the same terms
- Check spelling of all medical terms before the exam
What each criterion looks like at band 300, 350 and 400
The same six criteria, shown at three score points on the WCS internal scale (which tracks the official descriptors): band 300 (Grade C+), band 350 (Grade B), and band 400 (high Grade B). Under the 2026 rubric, the jump from 300 to 350 is almost always Purpose and Organisation, not Language.
| Criterion | Band 300 (Grade C+) | Band 350 (Grade B) | Band 400 (high Grade B) |
|---|---|---|---|
| Purpose | Announces the letter ("I am writing to inform you…") rather than the request. | States the request and the action wanted in the first two sentences. | Request, action and timeframe all explicit and calibrated to the recipient. |
| Content | Most relevant facts present, but one omission or one irrelevant inclusion. | All relevant facts present, selected for the recipient's needs. | Complete and prioritised — the most important fact comes first. |
| Conciseness & Clarity | Some courtesy padding or one repeated point. | Tight, with at most one redundant phrase. | No redundancy; every sentence carries new clinical meaning. |
| Genre & Style | Register mostly correct; one phrase too formal or too casual. | Register consistent with the recipient throughout. | Framing precisely matched to the recipient's role. |
| Organisation & Layout | Paragraphs present but not in the most useful order. | Logical order: purpose, history, current status, plan, closing. | Order optimised so the recipient can act after one read. |
| Language | Minor errors that do not impede meaning. | Clean grammar and precise clinical vocabulary. | Varied sentence structure, no errors, natural register. |
See the matrix applied to a complete letter in the band 350 discharge letter walkthrough, or test your own letter with the free Writing Checker.
"Most candidates who score below Grade B have strong grammar — the gap is almost always in content selection and task fulfilment. They include too much, include the wrong things, or never make their purpose clear. Grammar alone will not get you to 350."
How to Use the Criteria in Practice
Before writing
Identify the purpose, the reader, and which case note information is relevant to that reader. Criteria 1 and 2 are decided before you write your first word.
While writing
Check each sentence: does it serve the reader? Is it adding new information or repeating something already said? Criteria 3 and 4 are built sentence by sentence.
After writing
Review paragraph flow, check grammar and spelling, verify your opening and closing are complete. Criteria 5 and 6 are confirmed in your review phase.
After getting feedback
When you receive a correction, cross-reference each comment with the relevant criterion. Build a list of your personal weak areas to target in the next practice letter.
Related guides: Top OET writing tips · OET writing test format · Referral letter guide · Discharge letter guide
Frequently Asked Questions
What are the 6 OET writing criteria?
What score do I need for OET Grade B?
Which OET writing criterion is most important?
Did the OET writing criteria change in 2026?
What is the difference between a band 300 and a band 350 letter?
Related OET Writing guides
Continue your preparation with these related resources.
OET Scoring Criteria →
How the 6 criteria are assessed and where most candidates lose marks.
Grade B Sample Letters →
20 worked sample letters by profession × scenario with line-by-line annotations.
Mistake Clinics by Profession →
10 profession-specific mistake clinics — wrong vs right examples per criterion.
Grade A vs B vs C Compared →
Three letters from the same case notes at three bands — what moves you up one.
OET Writing Correction
See how your letter scores against all 6 criteria
Dr Mariam's OET writing team assesses every letter against the same 6 criteria your official examiner uses. You receive a detailed annotated PDF showing exactly where marks are being lost — and how to fix it.
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