Chalmers Writing Guide

Coherence & Cohesion

Coherence and cohesion are essential for aiding readability and idea communication.  Coherence is about the unity of the ideas and cohesion the unity of structural elements.  One way to do this is through the use of cohesive devices: logical bridges (repetition), verbal bridges (synonyms), linking words, and clear back referencing.  If these types of devices are missing in the text, it not only becomes more difficult to read the text, but also to understand its contents since the reader must guess how the various parts of the paragraph or text are connected, which will involve re-reading sentences or larger sections more than once.

See this film for a discussion of coherence and cohesion:

With logical bridges, the same idea of a topic is carried over (repeated) from sentence to sentence, and successive sentences can be constructed in parallel form. With verbal bridges, key words or synonymous words can be repeated, pronouns can replace nouns and transition words (as shown below) can be used.   In the paragraph below, words and phrases that serve to increase the coherence of the paragraph are highlight and underlined. As this sample paragraph indicates, coherence and cohesion in a paragraph is established by combining more than one device.


There are three components to a typical modern catalytic converter: one to effect the reduction of nitrogen oxides, another to facilitate the oxidation of carbon monoxide and hydrocarbons, and the third to maintain the correct abundance of oxygen. In the first stage the nitrogen oxides are reduced using a platinum catalyst, which facilitates their decomposition into nitrogen and oxygen.  In the next stage the carbon fragments are oxidized over a platinum/rhodium catalyst. Finally, the correct amount of oxygen is ensured by monitoring the amount of oxygen passing into the engine, and by incorporating into the catalyst a metal oxide that absorbs oxygen (by reacting with it to form a higher oxide) when the fuel mixture has too much oxygen and reverts to the lower oxide, releasing oxygen, when the mixture has too little (Atkins. P.W, 1991)

The topic sentence introduces the three stages which are then explained in more detail.


Verbal bridge:

The second sentence includes a key word “reduced”, linking the idea to the previous sentence though in a different form from earlier (“reduction”). A similar repetition occurs in the third sentence.


Logical bridge:

The processes of the first two stages are described in parallel form.


The final sentence sums up this process, clearly signalled by “finally”.

A more direct way of emphasizing the inherent logic of a paragraph is through the use of linking words and phrases which mark transitions within and between sentences. The table below gives a sample of such linking words and groups them based on the connection they illustrate/indicate

Example /


Result /

Contrast / Comparison

for example,

for instance,

that is,

In other words,



in addition,






as a result,

for this reason,

owing to this,







strangely enough,

of course,




on the contrary,

in contrast,

on the one hand, . . . on the other hand,

in comparison,




Back reference

at first,




in the end,


in conclusion,

in short,

to sum up,

first(ly), second(ly), third(ly),








Back referencing is another effective device for creating coherence, but this device must be used carefully because it can cause confusion rather than create clarity. Consider whether or not the use of back referencing is clear in the following example

Plagiarism is a recurrent problem, which is considered an important matter in university education. Chalmers is no exception to that and therefore has a strict policy regarding how it should be dealt with.

The back references are vague and bring up questions such as what does ’that’ refer to?

 Be more specific:

that could be "this situation"

 it could be "the issue of plagiarism"

It is perfectly acceptable to use back referencing, just be sure to make it clear. One way to do this, as exemplified in the remarks above, is to add a summary word to the back reference (e.g. this situation, where situation is the summary word). Using a summary word specifies the back reference, often making it much clearer.

In Summary

Connect ideas, sentences and paragraphs using a variety of cohesive devices:

• logical bridges (parallel construction) 

    • carry the same idea of a topic over from sentence to sentence, i.e. successive sentences are constructed in parallel form

e.g. In the first stage, an idea can be generated by using a mind-map and some discussion.  In the next stage, a clear plan of action can be produced in the form of a list.

• verbal bridges (back referencing/linking words) 

    • key words/phrases might be repeated in a number of sentences, or synonyms utilised instead to avoid exact repetition.

e.g. There are three stages to the pre-writing process: one to effect the generation of ideas, another to facilitate an action plan, and the third to research the information to be included in your text.  In the first stage, an idea can be generated by using a mind-map and some discussion.

  • words/phrases to link ideas between sentences for smooth transition

e.g. writing is a process, which can take a long time and involve many obstacles.  However, when you are finished, you’ll see that it was worth the effort.