Cohesion and Coherence
Cohesion refers to the grammatical and lexical links that hold a text together. Coherence refers to the logical flow of ideas. Both are essential for well-structured academic writing.
Cohesion
Cohesion is the way a text is linguistically held together through reference, substitution, ellipsis, conjunction, and lexical choice.
1. Reference
Using pronouns and determiners to refer back (or forward) to nouns.
The committee submitted its report. It was comprehensive. (it refers back to 'the report')
Both this finding and those of earlier studies suggest...
2. Lexical cohesion
Repeating key words, using synonyms, or using related terms.
The city experienced severe flooding. The disaster caused widespread disruption. (synonym)
Climate change affects ecosystems. These environmental shifts are accelerating. (related phrase)
3. Conjunction and discourse markers
Explicit signals of logical relationships: however, therefore, furthermore, in addition.
4. Substitution and ellipsis
Using 'one', 'do so', 'so', 'not' to avoid repetition.
Coherence
Coherence is the logical organisation of ideas so the text makes sense as a whole. A text can be cohesive but incoherent if the ideas do not connect logically.
| Cohesive (but incoherent) | Coherent |
|---|---|
| The policy was introduced in 2010. However, cats are mammals. | The policy was introduced in 2010. However, its effects were not felt until 2015. |
Principles of coherence
- One main idea per paragraph
- Topic sentences that preview paragraph content
- Ideas that build logically from sentence to sentence
- Smooth transitions between paragraphs
- A clear argument that progresses
Tip: After writing, check each paragraph for a clear topic sentence, and check each sentence follows logically from the one before. Good cohesion helps; coherence is more fundamental — without it, no amount of linking words will save a text.