Apostrophes, how to use them…

This is not strictly an APA rule, but here are some tips on the proper use of the apostrophe. Apostrophes (‘) usually indicate one of two things: a contraction, or a possessive state for a noun or proper noun.

EXAMPLE 1: POSSESIVE SINGLE NOUN
Simply add an apostrophe and an s after the noun to indicate a possessive state.

• The poet’s intent is to….
• The wolf’s prey….

EXAMPLE 2: POSSESIVE PLURAL NOUN ENDING IN S
Add an apostrophe after the s to indicate a possessive form of the pluralized noun – a second s is not required after the apostrophe.

• The doctors’ research….
• The wolves’ prey….

EXAMPLE 3: POSSESIVE PLURAL IRREGULAR NOUN NOT ENDING IN S
Certain pluralized nouns do not end in s (e.g., men, feet, phenomena). For those terms, add the apostrophe and an s after the irregular pluralized noun.

• The women’s duties included….
• The deer’s diet consists of….

EXAMPLE 4: SINGULAR PROPER NOUN
Add an apostrophe and s after any single proper noun.

• Hercules’s strength was….
• Leibowitz’s photography….

NOTE: Even if the singular proper noun ends with an s, add the apostrophe and s. Some texts will suggest that simple writing Hercules’ (without the ’s) is also acceptable.

EXAMPLE 5: POSSESSIVE PROPER NOUNS IN A SERIES (JOINT POSSESSION)
Add an apostrophe and s after the last proper noun in a sequence of proper nouns.

• Carter and Seybold’s paper outlines….
• Prokopiev, Turner, and Chen’s work….

You will use this form when you have multiple authors contributing to the same work.

EXAMPLE 6: POSSESSIVE PROPER NOUNS IN A SERIES (INDIVIDUAL POSSESSION)
Add an apostrophe and s after the each proper noun in a sequence of proper nouns.

• U2’s and INXS’s songs differed in….
• Shakespeare’s and Marlowe’s plays were….

Since the works were not collaborations, each proper noun must indicate an individual possessive state.

EXAMPLE 7: POSSESSIVE PLURALIZED PROPER NOUNS
If a proper noun is pluralized, only add the apostrophe.

• The Kravitzes’ investments were….
• The MacGregors’ land included…

WHEN WILL YOU NOT USE AN APOSTROPHE
Do not use an apostrophe for the pluralizing of abbreviations or numbers.

• PDFs
• PhDs
• 1980s

You will not use an apostrophe and s to indicate the possessive form of personal and relative pronouns.

INCORRECT FORM	CORRECT FORM
their’s	theirs
it's (contraction meaning: it is)	its
who's (contraction meaning: who is)	whose
That is her’s.	That is hers.
Our’s are over there.	Ours are over there.

CONTRACTIONS
It is STRONGLY advised that you never use contractions in an academic paper. It is considered poor form/style to do so. Use cannot instead of can’t; use do not and not don’t; and despite ain’t being in some dictionaries, it should never be used in an academic setting.

EXCEPTIONS
Some proper nouns employ an apostrophe, but do not indicate a possessive state or contractions (e.g., O’Neil, D’Angelo, etc.). O’clock (meaning: according to the clock) also employs the apostrophe, but neither a contraction nor a possessive state are implied.

Sources:
Flick, J., & Millward, C. (1993). Handbook for writers (2nd Canadian ed.). Toronto, Ontario, Canada: Harcourt Brace Jovanovich Canada.

Gibaldi, J. (2003). MLA Handbook for writer’s of research papers (6th ed.). New York: Modern Language Association of America.