Cohesion vs. Coherence, Explained Simply

Cohesion and coherence are graded together under a single IELTS Writing criterion, which is precisely why so many candidates conflate them — yet they measure two genuinely different things, and misunderstanding the difference leads to a specific, avoidable failure: essays that are stitched together with linking words yet still read as disorganised, or essays that flow logically but get marked down for lacking visible connective language. Knowing which one a weak paragraph is actually failing at is the first step to fixing it.

Cohesion is the mechanical, surface-level glue: linking words and phrases (however, therefore, in addition, as a result), pronoun reference back to something already named (it, this, they, such an approach), and lexical chains — related vocabulary that ties a paragraph's sentences to the same idea without repeating one word (funding, subsidy, financial support, public investment, all referring to one underlying concept across a paragraph). A reader can usually spot weak cohesion immediately: sentences sitting next to each other with no visible signal of how they relate.

Coherence is different: it's whether the writing actually makes sense as a connected argument when you step back from the sentence level. Are the ideas organised in a logical order? Does each paragraph build on what came before rather than repeating or contradicting it? Would a reader who had never seen the question still understand, from the essay alone, what point is being made and why? Coherence lives at the level of the whole essay, not the individual sentence.

It's entirely possible to write a paragraph that is mechanically well-linked while still being confusing. Consider: "Firstly, the government should fund the arts. Moreover, some people enjoy visiting museums. Furthermore, museums can be expensive to run. In addition, not everyone likes the same kind of art." Every sentence is connected to the next with a textbook linking word, yet the paragraph doesn't actually build an argument — it drifts between four loosely related observations that never add up to a single point. An examiner reading this sees correct linking words and a genuinely incoherent paragraph at the same time, and the incoherence is what gets marked down, despite the cohesive devices being technically accurate.

The reverse is rarer but instructive: "Public funding for the arts benefits everyone, not just those who attend galleries. A well-funded museum draws tourists, whose spending supports local businesses far beyond the museum's own walls. Schools nearby often use these spaces for free educational visits, extending the benefit to children who might otherwise never encounter original artwork." This has almost no explicit linking words, yet it is entirely easy to follow — each sentence connects logically to the one before through what it's actually about, not through a signal word. It would still likely score better with a little more explicit cohesion, but the underlying coherence is genuinely strong on its own.

The version that scores well needs both at once: "Public funding for the arts benefits everyone, not just those who attend galleries. A well-funded museum, for instance, draws tourists, and their spending supports local businesses far beyond the museum's own walls. In turn, schools nearby often use these spaces for free educational visits, extending the benefit to children who might otherwise never encounter original artwork." Here "for instance" and "in turn" make explicit connections that were already logically present, guiding the reader through a paragraph that was coherent to begin with. Cohesion, at its best, isn't decoration added afterward — it's making an already-logical structure visible on the surface.