Coherence and cohesion: what is actually being marked
A quarter of your Writing score, and the criterion candidates most often try to game. The usual attempt — adding more linking words — makes it worse.
Two different things in one criterion
Coherence is whether your ideas follow each other. Could a reader summarise your argument after one pass? Cohesion is the surface machinery that signals the connections: linking words, pronouns, repeated and substituted nouns.
They fail independently. An essay can be full of connectors and still incoherent, because the connectors announce relationships the ideas do not actually have. That is the more common failure, and it is the one produced by memorised templates.
Linking words: the trap
The advice to "use linking words" is repeated so often that candidates treat their count as the score. It is not. Overuse and mechanical use are weaknesses in their own right.
Firstly, pollution is a serious problem. Moreover, it affects health. Furthermore, governments should act. In conclusion, pollution is bad.
Four connectors, four sentences, no argument. Each one announces an addition, so nothing develops — the essay lists rather than reasons.
Pollution is usually framed as an environmental problem, but its clearest cost is medical: respiratory illness rates in the worst-affected cities are several times the national average. That cost falls on public health budgets, which is why the argument for regulation is financial as much as ethical.
Two connectors, both doing real work. But marks a genuine contrast; which is why marks a genuine consequence.
The test for any connector: remove it. If the relationship between the sentences is still obvious, the connector was decoration. If the sentences now seem unrelated, it was carrying meaning.
Paragraphing
Paragraphing sits inside this criterion, and it is worth being precise about what counts.
A response with no paragraph breaks at all is a real weakness. One unbroken block gives the reader no structure to hold on to, and it usually reflects an essay that was not planned. This is the paragraphing problem that costs marks.
A short paragraph is not a fault. There is no required number of paragraphs and no required length. A two-sentence paragraph that makes one point cleanly is fine. So is a four-paragraph Task 2 essay, or a five-paragraph one.
The working rule is one central idea per paragraph, visible in the first sentence or two. If you cannot say what a paragraph is about in a few words, it is doing more than one job and should be split — not because of length, but because the reader cannot follow two arguments at once.
The invisible half: referencing and substitution
This is what separates cohesion that reads naturally from cohesion you can hear. Instead of repeating a noun, competent writing points back at it.
- Pronouns. it, they, this, these, such — provided the reference is unambiguous. "This is a problem" after a paragraph with three ideas leaves the reader guessing which one.
- Substitution. Naming the same thing a second way — the policy, this approach, the measure — rather than repeating the full phrase.
- Ellipsis. Leaving out what is already understood, so the sentence does not restate its own context.
Candidates who repeat the same noun phrase in every sentence are penalised twice: once here, for absent referencing, and once under Lexical Resource, for repetition.
A quick self-check
- Read only the first sentence of each paragraph. Do they alone outline your argument? If not, your topic sentences are not carrying the structure.
- Count your connectors. More than roughly one per two sentences is usually decoration.
- Find every this and it and ask what exactly it refers to. If you hesitate, the examiner will too.
- Check that no paragraph makes two separate points.
Where it fits
Coherence and cohesion is one of four equally weighted criteria — see how IELTS Writing is scored for how the four combine. It is often the cheapest criterion to lift, because it responds to planning rather than to years of language acquisition, which makes it a useful target if you are trying to move from 7 to 8.
Not sure whether your linking is helping or hurting? IELTS Writing Checker scores coherence and cohesion separately from the other three criteria and points to the specific places it breaks down. Try it — writing is free, or see pricing.