Grammar is the most visible target in OET Writing — and paradoxically, it’s often not where most marks are actually lost. Candidates who obsess over grammar while neglecting Content and Organisation frequently plateau at Grade C.
That said, systematic grammar errors do cost marks on the Language criterion (scored /7), and in some cases bleed into Conciseness & Clarity. More importantly, certain grammar patterns are so common among OET candidates that fixing them produces an immediate, measurable improvement.
This post covers the five most common grammar errors in OET Writing, with clinical examples and corrected versions.
Where Grammar Sits in the OET Marking Scheme
| Criterion | Score | Relevance to Grammar |
|---|---|---|
| Purpose | /3 | Indirectly — a grammatically broken opening can obscure the reason for writing |
| Content | /7 | Indirectly — errors that create clinical ambiguity |
| Conciseness & Clarity | /7 | Directly — run-on sentences, convoluted phrasing |
| Genre & Style | /7 | Directly — incorrect register markers |
| Organisation & Layout | /7 | Minimal |
| Language | /7 | Primary criterion for grammar, spelling, punctuation |
Grade B target: 350–440 (converted from /40). A Language score of 5/7 is consistent with Grade B; 4/7 or below puts pressure on all other criteria to compensate.
The key insight: grammar errors are penalised proportionally to their frequency and their impact on meaning. An occasional article error won’t fail you. A systematic pattern of tense inconsistency that makes it unclear when events occurred will.
Error 1: Incorrect Article Use (a / an / the)
Article errors are the single most common grammar issue for OET candidates whose first languages do not use articles — this includes speakers of Filipino languages, Malayalam, Hindi, Arabic, and many others.
The rules in clinical writing context:
- “The” — use when referring to a specific, already-identified item or one that is unique in context
- “A / an” — use when introducing something for the first time or referring to one of many
- No article — used with uncountable nouns (pain, hypertension, management) and plural general nouns
Common errors and corrections:
| ❌ Error | ✅ Correction | Rule |
|---|---|---|
| ”She was admitted to a hospital." | "She was admitted to hospital.” | In British/Irish/Australian clinical English, ‘hospital’ as an institution takes no article |
| ”He has the hypertension." | "He has hypertension.” | Uncountable medical conditions take no article |
| ”She underwent the appendectomy." | "She underwent an appendectomy.” | First mention of a procedure — use ‘an‘ |
| “Patient has a pain in right shoulder." | "The patient has pain in the right shoulder.” | ’Pain’ is uncountable; ‘right shoulder’ is a specific anatomical location |
| ”A chest X-ray showed consolidation." | "Chest X-ray showed consolidation.” OR “A chest X-ray showed consolidation.” | Both acceptable; ‘a’ is correct if you’re introducing it for the first time |
British vs. American usage: OET uses British English conventions. “She was admitted to hospital” (no article) is correct in British English. “She was admitted to the hospital” is American English — acceptable but not preferred in OET.
Practice sentence — spot the errors:
The patient was transferred to a ward after the surgery. She had the fever and the tachycardia on first postoperative day.
Corrections: “a ward” → “the ward” (specific ward she was transferred to); “the fever and the tachycardia” → “a fever and tachycardia” (fever is countable and being introduced; tachycardia is uncountable); “on first postoperative day” → “on the first postoperative day.”
Error 2: Subject-Verb Agreement with Clinical Nouns
Clinical writing involves collective nouns, medical team references, and compound subjects that frequently trip up non-native writers.
Common clinical subject-verb errors:
| ❌ Error | ✅ Correction | Note |
|---|---|---|
| ”The team were consulted." | "The team was consulted.” | In standard clinical written English, collective nouns take singular verbs |
| ”His blood pressure and heart rate was elevated." | "His blood pressure and heart rate were elevated.” | Compound subject joined by ‘and’ takes plural verb |
| ”A course of antibiotics were prescribed." | "A course of antibiotics was prescribed.” | The subject is ‘a course’ (singular), not ‘antibiotics‘ |
| “The results of the blood test was normal." | "The results of the blood test were normal.” | The subject is ‘results’ (plural), not ‘test’ |
A reliable test: mentally remove the prepositional phrase (“of antibiotics”, “of the blood test”) to find the true subject, then match the verb.
“A course [of antibiotics] → was prescribed.” ✓ “The results [of the blood test] → were normal.” ✓
Error 3: Tense Sequencing in Clinical Histories
OET letters frequently mix past and present tense in ways that create ambiguity about when events occurred. Examiners flag this under both Language and Conciseness & Clarity.
The OET tense framework:
- Past simple — for completed events (admission, procedures, investigations performed, past diagnoses)
- Present simple — for ongoing conditions, current medications, and the patient’s current status
- Past perfect — for events that occurred before another past event (“She had been prescribed metformin prior to admission”)
- Present perfect — for conditions that began in the past and are still relevant (“She has been managed conservatively for three weeks”)
Common tense errors:
| ❌ Error | ✅ Correction | Issue |
|---|---|---|
| ”He was admitted and presents with chest pain." | "He was admitted and presented with chest pain.” | Inconsistent shift from past to present for a completed admission event |
| ”She undergoes surgery last Tuesday." | "She underwent surgery last Tuesday.” | ’Last Tuesday’ is a past time marker — requires past simple |
| ”The patient had a fall and is now treated with analgesia." | "The patient had a fall and is now being treated with analgesia.” | Present progressive for ongoing treatment is more precise |
| ”She has been discharged yesterday." | "She was discharged yesterday.” | ’Yesterday’ is a specific past marker — use past simple, not present perfect |
Before and After — Tense Inconsistency in a Clinical History Paragraph:
❌ With errors:
Mr. Hassan was admitted on 12 April with shortness of breath. He has a history of COPD and takes salbutamol regularly. On admission, his oxygen saturation is 88% on room air. He receives nebulised bronchodilators and is now improved.
✅ Corrected:
Mr. Hassan was admitted on 12 April with shortness of breath. He has a history of COPD and takes salbutamol regularly. On admission, his oxygen saturation was 88% on room air. He received nebulised bronchodilators and has since improved.
What changed: “is 88%” → “was 88%” (past event on admission); “receives” → “received” (completed treatment); “is now improved” → “has since improved” (present perfect for ongoing outcome).
Error 4: Misuse of Relative Clauses (who / which / that)
Relative clause errors are common and affect the clinical precision of your letter — particularly when describing patients, conditions, and procedures.
The rules:
- Who — refers to people
- Which — refers to things (and is used for non-restrictive/non-defining clauses)
- That — refers to things (and is used for restrictive/defining clauses)
Common OET errors:
| ❌ Error | ✅ Correction | Note |
|---|---|---|
| ”The patient which was admitted…" | "The patient who was admitted…” | Patients are people — use ‘who‘ |
| “The medication that she is allergic to…" | "The medication to which she is allergic…” | Formal clinical register avoids ending with a preposition |
| ”She has asthma, that is well controlled." | "She has asthma, which is well controlled.” | Non-restrictive clause — use ‘which’ with a comma |
| ”The wound which is on her left leg is healing." | "The wound on her left leg is healing.” OR “The wound, which is on her left leg, is healing.” | Simplify when the relative clause adds only location |
Register note: In formal clinical writing, “the medication to which she is allergic” is preferred over “the medication that she is allergic to.” The OET Genre & Style criterion rewards clinical register precision — preposition stranding (ending with ‘to’, ‘for’, ‘from’) is acceptable but slightly informal.
Error 5: Run-On Sentences and Comma Splices
Run-on sentences and comma splices are among the most penalised Language errors in OET Writing because they also cost marks on the Conciseness & Clarity criterion. A letter that is difficult to parse is not clinically useful.
What a run-on sentence looks like:
The patient was admitted with severe abdominal pain she has a history of gallstones and she has been vomiting for two days and she is currently nil by mouth and her pain is rated 8/10.
This is one sentence doing the work of five. It fails Language (punctuation/structure) and Conciseness & Clarity (not easy to act on).
What a comma splice looks like:
She was reviewed by the surgical team, they recommended conservative management initially.
Two independent clauses joined by only a comma — this is incorrect. Options to fix:
- Full stop: She was reviewed by the surgical team. They recommended conservative management initially.
- Semicolon: She was reviewed by the surgical team; they recommended conservative management initially.
- Coordinating conjunction: She was reviewed by the surgical team, and they recommended conservative management initially.
- Subordinating conjunction: Following review by the surgical team, conservative management was recommended initially.
Before and After — Run-On in OET Context:
❌ Run-on version:
Mrs. Nguyen is a 55-year-old woman who was admitted on 18 April with increasing shortness of breath and she has a history of heart failure and she is on furosemide and ramipril and her chest X-ray shows bilateral pleural effusions and she has been commenced on IV diuretics.
✅ Corrected version:
Mrs. Nguyen, a 55-year-old woman with a background of heart failure, was admitted on 18 April with worsening dyspnoea. She is currently managed with furosemide and ramipril. Chest X-ray demonstrated bilateral pleural effusions, and she has been commenced on intravenous diuretics.
Word count: Run-on version: 64 words in one sentence. Corrected version: 52 words in three sentences — shorter, clearer, and higher scoring on both Language and Conciseness & Clarity.
Quick Reference: The 5 Errors at a Glance
| Error | Criterion Impact | Quick Fix |
|---|---|---|
| Article errors (a/an/the) | Language | Remove article for uncountable nouns; use ‘the’ for specific/identified items |
| Subject-verb agreement | Language | Identify the true subject; ignore prepositional phrases |
| Tense inconsistency | Language + Conciseness | Past simple for completed events; present simple for current status |
| Relative clause misuse | Language + Genre | ’Who’ for people; ‘which’ for non-defining clauses; ‘that’ for defining |
| Run-on sentences | Language + Conciseness | One idea per sentence; use full stops, semicolons, or subordination |
Grammar Is Not Your Biggest Problem
If you’re making all five of the errors above frequently, grammar is worth addressing. But if your Language criterion is already around 5–6/7 and you’re still not reaching Grade B, the issue is almost certainly Content or Organisation — not grammar.
Most OET candidates who struggle to reach Grade B are:
- Missing required case note items (Content)
- Including distractors (Content)
- Organising chronologically rather than thematically (Organisation)
These criteria carry up to /7 each and are far harder to self-assess than grammar. Criterion-specific feedback — not grammar correction alone — is what moves the needle.
Practise with a free scored letter at /blog/oet-writing-practice-test-free to find out which criteria are actually costing you marks.
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