How OET Writing Is Scored
Since August 2018, your OET writing letter is marked by two trained assessors against six criteria — Purpose, Content, Conciseness & Clarity, Genre & Style, Organisation & Layout, and Language — published by CBLA (Cambridge Boxhill Language Assessment), which owns the OET. Their marks are combined and scaled to a result from 0 to 500 and a grade from A to E, with Grade B (a score of 350) the level most healthcare regulators require. This page explains exactly how those marks are produced — and to turn a specific number into a grade, use the OET score calculator.
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In short
- Two trained assessors mark your letter against six criteria — Purpose on a 0–3 band, the other five on 0–7.
- Their marks are combined and scaled to a 0–500 writing result, reported as a grade from A to E.
- Grade B = 350 is the writing level most regulators require. There is no "B+" grade.
How Your Writing Score Is Produced
Your 0–500 writing result is not a single reader's opinion. It is built in four steps, which is why targeted feedback on the right criterion moves your grade.
- 1
Two assessors mark independently
Every writing script is marked by two trained CBLA assessors who do not see each other's marks. This double-marking moderates any unusual single judgement.
- 2
Each criterion is scored on its own band
Purpose is scored on a 0–3 band; Content, Conciseness & Clarity, Genre & Style, Organisation & Layout, and Language are each scored on a 0–7 band. Purpose therefore carries slightly less weight than the other five — but all six matter.
- 3
Marks are combined and scaled to 0–500
The criterion marks from both assessors are combined and statistically scaled onto the 0–500 OET scale, so the writing sub-test is comparable across different test versions.
- 4
The 0–500 score maps to a grade A–E
Your scaled score is reported as both a number and a letter grade. Grade B (350) is the level most healthcare regulators require in writing.
OET Writing Grade Scale (Score to Grade)
The official numerical bands that map your 0–500 writing score to a grade. These are the same bands used across all four OET sub-tests. To convert a specific number, use the OET score calculator.
| Writing score | Grade | What it means |
|---|---|---|
| 450–500 | A | Very high proficiency — well above any regulator requirement |
| 350–440 | B | The standard most regulators require (NMC, GMC, HCPC, AHPRA) |
| 300–340 | C+ | Accepted by some regulators in 1–2 sub-tests when combining sittings |
| 200–290 | C | Below most healthcare requirements |
| 100–190 | D | Well below requirements |
| 0–90 | E | Lowest band |
Each sub-test is graded separately — there is no overall OET score, so a strong Reading grade cannot lift a weak Writing grade. Source: CBLA (Cambridge Boxhill Language Assessment) official scoring information.
The 6 OET Writing Assessment Criteria
Each criterion is scored by two trained CBLA assessors — Purpose on a 0–3 band, the other five on 0–7. Your combined scores are scaled to a writing result from 0 to 500, reported as a grade from A to E.
1. Purpose
Is the reason for writing immediately clear? Does the opening establish why the letter is being sent and what the writer wants the reader to do?
2. Content
Is the necessary clinical information included and accurate? Has the writer selected the relevant case notes and left out what the reader does not need?
3. Conciseness & Clarity
Is the letter free of repetition and padding? Does every sentence carry new, relevant information that the reader can follow on a first read?
4. Genre & Style
Is the tone and register appropriate for professional healthcare correspondence and for this specific reader? Does it read as authentic clinical writing?
5. Organisation & Layout
Is information logically sequenced and well-paragraphed? Does the letter follow professional letter conventions (salutation, structure, sign-off)?
6. Language
Are grammar, vocabulary, spelling, and punctuation accurate and appropriate for the clinical context, with enough range to communicate precisely?
What Each Criterion Measures in Detail
The following breakdown is based on the official OET assessment criteria published by CBLA (Cambridge Boxhill Language Assessment), which owns the OET. Based on our analysis of 11,000+ corrected letters, the criteria most candidates struggle with are Purpose, Content, and Genre & Style — not Language. For a criterion-by-criterion deep dive on where marks are lost, see the full OET writing criteria guide.
1 Purpose
This criterion assesses whether the reason for writing is immediately clear to the reader. The opening must establish why the letter is being sent and what the writer wants the reader to do — the single most common point of failure in OET letters.
2 Content
This criterion measures whether the right clinical information has been selected from the case notes and reported accurately. It assesses the candidate's judgment about what the reader needs to know — including what to leave out.
3 Conciseness & Clarity
This criterion assesses whether information is communicated efficiently and unambiguously. A strong letter has no repetition or padding, and every sentence is clear on a first read. Courtesy filler and repeated points lower the score here.
4 Genre & Style
This criterion evaluates whether the tone, register, and conventions match professional healthcare correspondence and the specific reader. It goes beyond grammar to assess whether the letter reads as authentic clinical writing.
5 Organisation & Layout
This criterion assesses how the letter is structured and sequenced. A well-organised letter guides the reader logically from the purpose through the supporting detail to the closing request, using clear paragraphing and professional letter conventions.
6 Language
This criterion assesses the accuracy and range of grammar, vocabulary, spelling, and punctuation. Since August 2018 it combines the earlier grammar/cohesion and vocabulary areas into a single criterion covering all language control.
What Grade B Requires in Each Area
Grade B (score of 350) is the minimum accepted by most healthcare regulatory bodies, including the NMC, GMC, and AHPRA. To achieve it, candidates need consistently strong scores across all six criteria — there is no single area you can afford to neglect.
Purpose
The reason for writing is clear from the opening. The reader can immediately tell what is being requested and why, with no vague or generic introduction.
Content
Case notes are accurately interpreted and the relevant information is selected for the reader. No significant factual errors or critical omissions.
Conciseness & Clarity
The letter is focused, with at most minor redundancy. Information is communicated clearly without repetition or courtesy padding.
Genre & Style
Tone and register are consistently professional and appropriate for the reader. Minor lapses in style do not impede communication.
Organisation & Layout
The letter follows a logical structure with clear paragraphing. Layout conventions are observed and information flows naturally from opening to closing.
Language
Grammar, vocabulary, spelling, and punctuation are generally accurate with good control. Minor errors do not impede meaning.
Frequently Asked Questions
How is OET writing scored?
Since August 2018, OET writing is scored across six criteria by trained assessors at CBLA (Cambridge Boxhill Language Assessment, which owns the OET). The criteria are: Purpose, Content, Conciseness & Clarity, Genre & Style, Organisation & Layout, and Language. Each criterion is scored by two assessors — Purpose on a 0-3 band and the other five on 0-7 — and the six criterion scores are scaled to an overall writing result from 0 to 500, reported as a grade from A (highest) to E (lowest).
How do the six criteria become a single writing score?
Two trained assessors mark your letter independently against all six criteria — Purpose on a 0–3 band and the other five on 0–7. Their marks are combined and statistically scaled to produce your writing result from 0 to 500, which is then reported as a grade from A to E. Because two assessors mark every script, an unusual single mark is moderated rather than decided by one reader.
What is the OET writing grade scale?
OET reports your writing as a numerical score from 0 to 500 and a letter grade: A is 450–500, B is 350–440, C+ is 300–340, C is 200–290, D is 100–190, and E is 0–90. There is no 'B+' grade. Most healthcare regulators require Grade B, a score of 350, in the writing sub-test. To convert a specific score to a grade, use the OET score calculator.
What score do I need for Grade B in OET writing?
Grade B in OET writing corresponds to a score of 350 out of 500. To achieve it, candidates need consistently strong performance across all six criteria: a clear Purpose, accurate and relevant Content, Conciseness & Clarity without repetition, an appropriate Genre & Style for the reader, logical Organisation & Layout, and accurate Language. A weakness in any single criterion can pull the overall result below 350.
Which OET writing criterion is the hardest to score well on?
Based on our analysis of 11,000+ corrected letters, the criteria most candidates struggle with are Purpose, Content, and Genre & Style, not Language. Purpose requires an opening that immediately establishes why the letter is being written; Content requires selecting the right case-note information for the reader; and Genre & Style requires a professional tone and register that go beyond general English proficiency.
Are all six OET writing criteria weighted equally?
Not quite. Five criteria — Content, Conciseness & Clarity, Genre & Style, Organisation & Layout, and Language — are each scored on a 0-7 band, while Purpose is scored on a 0-3 band, so it carries slightly less weight. All six still matter: a weakness in any single area can pull your overall result below Grade B.
Get Scored on All 6 Criteria
Our OET writing correction service assesses your letter against all six official criteria and provides specific, actionable feedback to help you improve where it matters most.