Appropriate punctuation acts like a set of 'road signs' to guide the reader through the ideas expressed in your sentences. Punctuation marks can tell the reader when to slow down, speed up and stop. By breaking up your sentences, they contain and structure your ideas. This guide includes advice on using some of the most common types of punctuation.
Punctuation in brief
Commas are used to break up different parts of a sentence. They allow someone to make sense of what they are reading. Commas occur where ideas are grouped, to make it easier to understand these ideas. It may be helpful to think of commas as places where a reader might draw breath. The comma forms a natural place in a sentence where the reader can pause, to make sense of an idea. As a comma signifies a pause, it follows natural speech pattern. Here are some of the ways it can be used.
To separate words in a list:
He lost his house, his heritage, his hair and his handkerchief.
To separate parts of a sentence:
Firstly, I would like to consider the merits of supplementing the diet with zinc extract. Secondly, vitamin C can be introduced to combat infection.
Here the comma separates the first word from the body of the sentence, to indicate that this idea is only the first.
To separate two parts of a linked idea:
After the French Revolution had taken place, many other European countries were concerned about civil unrest.
Many scientists believe in evolution, although some are trying to disprove Darwin's Theory of Evolution.
To separate a final phrase, which is an afterthought:
Few people enjoy arduous and demanding exams, especially on Saturdays.
I would like to run the London Marathon, if I were fit.
The semi-colon contains a comma and a full stop. It may be helpful to think of semi-colons as halfway between the two. They are used in the following ways:
To link sentences that are closely related:
The night sky was the deepest sapphire; Claire realised that she had not observed its beauty until now.
A full stop between the two sentences would detract from Claire's observation, and a comma would not make enough of a break to allow the reader to make sense of the two ideas.
To link sentences that are in opposition to each other:
His research methods were fundamentally flawed; nonetheless, he collected the data.
In each of the examples above, the set of words after the semi-colon must be able to stand as a sentence on its own. However, there is a very common use of the semi-colon where this is not the case:
To separate items in a list:
Mrs Brown was assisted by other members of staff: Dr Hume from Animal Management; Mr Tredwell from Science; and Dr Houghton from Soil Science.
When a colon is used in a sentence, the parts it separates do not need to be complete sentences in their own right. Colons are used in the following ways:
To introduce a list:
The results of the indoor team games were as follows: Hayes came first, Hampson and Collier were joint second, and Chapman came last.
To link two sentences thematically:
Psychological studies into domestic violence are usually centred on an idea of the nuclear family: Henry Davis decided that he should undertake a more radical approach to research in this area.
Here the two sentences could exist separately, but by connecting them with a colon the reader is led from one idea to the next.
To draw out a conclusion:
Language acquisition is a difficult but immensely rewarding task: without it, there is little hope for global communication.
Here, what is said in the first sentence is contextualised by what is said in the second sentence.
There are two uses for the apostrophe:
1. To indicate possession (ownership)
2. To mark contraction (letters or words omitted)
The possessive apostrophe
The possessive apostrophe follows directly after the person, people or thing/s that own/s something.
Singular possession (one owner)
• The student’s book (one book belongs to one student)
• The student’s books (several books belong to one student)
• A year’s work (the work of one year)
• A person’s rights (the rights of one person)
Plural possession (more than one owner)
• The students’ book (one book belongs to several students)
• The students’ books (several books belong to several students)
• Three years’ work (the work of three years)
As you can see, the apostrophe usually comes before the 's' if the subject is single ('the student’s), and after the 's' if it is plural ('the students').
Collective nouns with possessive apostrophes
This can sometimes appear confusing when a collective noun is involved (i.e., a noun that is grammatically singular but refers to a plural entity). For example:
• People’s rights (the rights of all people)
• Indigenous peoples’ rights (the rights of several indigenous peoples, i.e., several groups of
people)
• The family’s view is…. (the view of one family)
• The families’ views are…. (the views of several families)
• The audience’s reaction on the night….
• The audiences’ reactions to the play across the tour….
• The children’s play area
Possession with a name (proper noun)
You will sometimes see disagreement about how to indicate possession with a name (proper noun). For example, in referring to the Ghost Stories of (i.e. belonging to) the novelist Henry James:
The work has been compared to Henry James’s Ghost Stories....
The work has been compared to Henry James’ Ghost Stories....
In fact, both are correct: this is a stylistic choice. Most modern style guides (and online copy) tend to favour the simpler second option of just one s. As ever, be consistent in your choice.
Contractions
Contractions are when words are run together to produce a shortened version (closer to spoken language), the apostrophe is used to show where the missing letters belonged.
For example:
Common issues related to possession: Whose (possession) and Who’s (who is)
Mark Rothko, whose abstract expressionist paintings instituted colour-field painting, was born in.... If you find yourself instead writing - who’s - then delete! Who’s is a contraction of ‘who is’.
Contractions are used in informal writing. Essays and reports should not contain informal writing.
Round brackets/parentheses ( )
The official name for round brackets (like these) is parentheses. They are used in pairs around groups of words introducing an extra idea e.g. an explanation or afterthought to be kept separate from the rest of the sentence. A sentence should still make complete sense without the words in parentheses. Extra text that is separated out like this is called parenthetical text.
For example
He always hands in his work on time (he is a well organised student) after carefully checking it.
Sometimes a whole sentence is parenthetical. When this is the case, include your punctuation, specifically the full stop/period within the parentheses.
“The sheer decibel level of the noise around us is not enough to make us cranky, irritable, or aggressive. (It can, however, affect our mental and physical health, which is another matter.)"
—Maya Angelou, I Know Why the Caged Bird Sings
For Citations
Brackets/parentheses are also used a lot in academic writing to separate citations from the rest of the text:
Storytelling activates the brain’s insular cortex and allows us to experience sensations such as excitement or disgust (Widrich, 2012).
or
Robinson (2001) suggests that Western culture has an obsession with academic achievement and fails to recognise the worth of creative ability.
Notice how the use changes dependent on the sentence structure. If the author's name is mentioned in the text, only the date is bracketed otherwise both name and date are included.
Square brackets [ ]
Integrating quotation
Square brackets can be used when you include quotation in your work, and further words are needed within it to make the meaning clear, or ensure it fits grammatically into the flow of your sentence.
Example: The first cohort [year one associate physicians] agreed with the decision.
Example: It is important to get students in the ‘right mood to think [by] gaining their attention’ (Cowley, 2004:8).
Indicating a spelling error in a quoted source text
If there is an error or an unconventional spelling in a direct quote you are using, write [sic] after it. Sic is Latin for ‘thus’ and is a way of showing that the error is not yours.
Example: ‘The children did not recieve [sic] any rewards for this’ (Green, 2002:19). (This indicates here that receive is misspelt.)
Braces { } < >
Braces { } < > Brace brackets {these} or angle brackets should only be used in specialist texts (maths, tabulations etc.).
Hyphens
In compound words
Hyphens are used to join two words together to make a compound word:
Note that not all compound words need hyphens (e.g. flowerpot, lipstick).
Take-away
Full-time
Well-being
In general, lots of hyphenation is to be avoided. Running words together like ‘playgroup’ for example, is now much more common than writing ‘play-group’. The main place this is still seen is when the writer wants to avoid the same letter meeting, for example, writing ‘self-financing’ instead of the odd-looking ‘selffinancing’. Use your judgement as to what looks right and if in doubt check a dictionary.
Two-word adjectives
Hyphens are also used to join two words together to create a single adjective:
She was a well-respected professional.
This is a university-wide policy.
However, do not hyphenate these words if they follow the nouns they modify:
As a professional, she was well respected.
This policy is college wide.
Dashes
Dashes play a similar role to parentheses in text—although they can be used singly as well as in pairs. When used singly they are used to replace a comma or a semi-colon but give extra emphasis to the separated text.
Since 2007, the consensus of the economic establishment—bankers, policymakers, CEOs, stock analysts, pundits—has been catastrophically wrong.
Surprisingly, climate change is still contested within some academic circles—nonsensical given the evidence
Note: although MS word converts a hyphen to a longer en-dash automatically when you put spaces at either side of it (and press space or enter after the following word) this is not actually the correct form of punctuation. To get a true em-dash in MS Word and some other word processors, use Ctrl-Alt with the minus sign (the one on your number pad).
Ellipsis ...
Ellipsis is the use of three dots to show an incomplete quote. This is a good way to shorten quotes so that you only use the relevant information for your essay.
Example: ‘Writing cannot be separated from other processes such as reflection, goal-setting, organisation and research … [and] in practice you will find that they are interrelated’ (Cottrell, 2010:167).
Note: When you use ellipsis … the sentence should still make sense. If you need to add words to complete the sense of the sentence, these should appear in square brackets, as in the example above.