Apostrophes have two main uses:
- Indicating possession (e.g. The student’s paper)
- Indicating a contraction (e.g. She’s writing a paper)
Contractions should be avoided in academic writing, but possessive apostrophes are used in all types of writing. Make sure to use them correctly, especially when dealing with plurals and abbreviations.
|This study examines the company’s efforts to expand.|
I highly recommend Sharon’s salon.
|My parents’ support was essential.|
The crowd’s applause could be heard for miles.
|In the last quarter, BP’s profits dropped.|
|The results are surprising.|
Remember what happened three Christmases ago?
|Several NGOs were present at the conference.|
We can identify the following KPIs.
|The 1920s was a golden age for art.|
During the 2010s politics slid into confusion.
|The cobra reared its head.|
Whose snake is that?
Possessive apostrophes with singular nouns
Apostrophes are used to indicate that something belongs to something or someone else.
To indicate possession with a singular noun, add ’s at the end of the word. This also applies to names and other proper nouns.
- The car’s windscreen is foggy.
- Rome’s backstreets are charming.
- A series of actions led to Captain Cook’s demise.
- The princess’s role has become less traditional.
- Doris’s new haircut was alarming.
- Mr Jones’s new dog won’t stop barking.
- The details of Jesus’s life remain a matter of debate.
Some guides allow you to add only an apostrophe in cases where the extra s would be awkward to pronounce aloud. If in doubt, however, adding ’s is the safest choice.
Note that when you are citing a source, the apostrophe is attached to the author’s name, not to the in-text citation.
- This paper builds on Adams (2017)’s research.
- This paper builds on Adams’s (2017) research.
Possessive apostrophes with plural nouns
Most plural nouns already end in s. In this case, to indicate possession, add only an apostrophe to the end of the word. This also applies to words where the singular and the plural take the same form.
- The flood destroyed the beavers’ dam.
- We present new evidence of the pirates’ intentions.
- The two species’ habitats are very different.
The same rule applies to proper nouns and singular entities that end with a plural noun.
- The Smiths’ house is old and creaky.
- The United States’ military budget is far larger than any other country’s.
- The sheep’s wellbeing is a priority.
- The children’s toys were broken.
- Pollen’s harmful effects are well known.
- The ANC’s history is complex and controversial.
Pronouns stand in for nouns. Possessive pronouns (e.g. mine, yours, hers, his, our, their, its) indicate that something belongs to someone or something. These pronouns do not take an apostrophe.
- Is this snake your’s?
- Is this snake yours?
- The cat arched it’s back.
- The cat arched its back.
Indefinite pronouns (e.g. someone, something, anybody) do take an apostrophe.
- Is this somebodys snake?
- Is this somebody’s snake?
- This match could be anybodys game.
- This match could be anybody’s game.
When multiple nouns jointly own one noun, an apostrophe is added after the last noun only.
- Frida and Diego’s love was complicated.
- This solution was first suggested in McDonald, Ferriss and Bane’s well-known paper.
In these examples, the same love is possessed by both Frida and Diego, and the same paper was written collectively by McDonald, Ferriss and Bane.
When multiple nouns individually own other nouns, however, add an apostrophe after all of the owning nouns.
- The scientist’s and the robot’s abilities were quite different.
- The freezing of pipelines is both the engineers’ and the operators’ problem.
In these examples, the scientist and the robot possess two different sets of abilities, and the engineers and the operators face two separate kinds of problem.
Sometimes one or more letters are omitted to shorten a word or term. An apostrophe is used to indicate missing letters.
- It is → it’s
- I am → I’m
- She is → She’s
- Would not → wouldn’t
However, contractions are informal and are usually not appropriate to use in academic writing.
Apostrophes to form plurals
In English, an apostrophe should almost never be used to form a plural, including with acronyms and decades.
- My parents were born in the 1960’s. They both have PhD’s.
- My parents were born in the 1960s. They both have PhDs.
There are rare exceptions to this rule, such as pluralizing letters of the alphabet.
- Cross the i’s and dot the t’s.
Possessive pronouns vs contractions
One of the most common apostrophe mistakes is confusing possessive pronouns with contractions that look or sound similar. Always pay attention to whether an apostrophe is intended to indicate possession or a contraction, and remember that possessive pronouns don’t take apostrophes.
It’s vs its
It’s is a contraction of it is.
- It’s unfortunate that wind turbines are expensive.
Its is a possessive pronoun indicating that something belongs to it.
- An automated system can correct its mistakes.
They’re vs their
They’re is a contraction of they are.
- The managers can’t see you because they’re in a meeting.
Their is a possessive pronoun indicating that something belongs to them.
- Jaguars drag their prey to secluded areas.
Who’s vs. whose
Who’s is a contraction of who is or who has.
- It remains unclear who’s been setting these traps.
Whose is a possessive pronoun indicating that something belongs to them.
- It remains unclear whose idea this was.