Conjunctions in essays and dissertations

Using conjunctions correctly in academic writing

If an essay, dissertation, or thesis is to be successful and impress the examiner, it is essential that the text flows naturally and that every argument is presented clearly. If sentences are too short, the work will appear as a list of statements which the reader will find extremely uninteresting. Conversely, if sentences are too long, the text will be unclear and fail to present the argument effectively. These two potential hazards can be avoided by the correct use of conjunctions.

What are conjunctions?

Conjunctions are words that connect phrases, clauses, and sentences, enabling the text to flow well and clearly. The most frequently used conjunctions are ‘and’, ‘but’, ‘or, and ‘because’.

Is it incorrect to begin a sentence with a conjunction?

Many people will remember being told in school that they should ‘never start a sentence with a conjunction’. The rationale for this is that a conjunction is a ‘joining’ word. However, there is no specific grammatical rule which states that a sentence cannot begin with a conjunction. For instance, writers such as Shakespeare, Blake, and Kipling often began sentences with a conjunction. In fictional work and in spoken language, this can be an effective strategy, for example: There was a full moon. And it was cold.

Doing so is mainly a matter of authorial style. However, in academic writing, it is generally better not to begin a sentence with a conjunction.

The conjunction ‘and’

Below is a simple illustration of how ‘and’ can be used to improve the flow of the text:

The essay was informative. It was interesting to read.

The essay was informative and interesting to read. 

Using ‘and’ with commas

Although some people argue that a comma should never be used with ‘and’, it is sometimes necessary to do so. For instance, consider the following example: There is abundant life on the earth and the moon has no signs of life. 

In this case, there should be a comma after ‘earth’, otherwise the somewhat confusing impression is given that both the earth and the moon have abundant life. A better way of saying this would be to use ‘but’ rather than ‘and’. For instance: There is abundant life on the earth, but the moon has no signs of life. 

Overusing ‘and’

The conjunction ‘and’ should not be overused in academic writing as it gives the impression of an amateur or immature writing style, for example: The university offers courses in physics and mathematics and astronomy and chemistry.

It would be much better to write this as:

The university offers courses in physics, mathematics, astronomy and chemistry.

A further argument arises as to whether there should be a comma after ‘astronomy’. This is known as the serial or Oxford comma, which can be a controversial topic. If you are unsure about whether to use this, consult the style guide of your university. There are some occasions where the Oxford comma is necessary in order to avoid confusion, for example: I arrived at the party with the band, Stan and Gerald.

In this instance, the impression given is that Stan and Gerald is the name of the band. The addition of the Oxford comma clarifies that the band, Stan, and Gerald are, in fact, three separate entities: I arrived at the party with the band, Stan, and Gerald. 

Using ‘and’ in progression and comparison

Consider the following sentence: The average age of the ships in the fleet is becoming higher and higher.

This refers to a gradual aging of the fleet. However, in academic writing it is better to say: The average age of the ships in the fleet is becoming increasingly higher.

The word ‘and’ can also be used to make a comparison, for example: There are cars and there are cars!

This conveys the meaning that some cars are better than others.

The conjunction ‘or’

When using ‘or’, it should be remembered that it presents one of two (or more) alternatives, for example: The walls should be painted blue or green. This conjunction can be used as a pair ‘either…or’ or as a negative ‘neither…nor’, for example: I have neither the time nor the inclination to read this book.

The conjunction ‘because’

This conjunction is used to convey cause and effect, as in the following example:

The written examination was cancelled because of the pandemic.

However, ‘because’ can also have a different meaning:

I believe that the shop is closing because the manager told me.

This does not mean that the reason for the closure is because the manager told the writer, but rather the writer believes this to be true because the manager told him or her. To make this clearer, it would be better to express this differently: The manager told me that the shop is closing; therefore, I believe this to be true.

The conjunction ‘but’

This conjunction can link two clauses where one justifies the other, as shown in the following example:

The experiment was time-consuming but it verified the hypothesis. 

The word ‘but’ can also be used as a preposition to mean ‘except’:

Everyone but the principal knew that the students were planning a sit-in.

In spoken language, ‘but’ is increasingly used as a standalone expression:

Heavy rain fell all night … But. … there were no floods.

This style should be avoided in academic writing.

Subject-Verb Agreement

Ensuring agreement between subject and verb is essential in academic writing, and extra care needs to be taken when ‘and’ is used, in which case the verb is almost always plural:

Philosophy, history, and religion are the main subjects taught at the university. 

However, please note the following case where the singular is used:

The dissertation, which presents the results of the study on meteorology, climate change, and biodiversity, is interesting to read.

In this example, the singular verb is used because ‘dissertation’ is the subject.

A similar example is: Harrow and Wealdstone is a railway station near London.

The singular is used here because the name refers to one railway station. However, it would be correct to say: Harrow and Wealdstone are two communities served by one railway station. 



Allen, Robert (1999). Pocket Fowler’s Modern English Usage. 2nd ed, 2008. Oxford; Oxford University Press.  

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