Apostrophes are punctuation marks used to indicate possession. The placement of an apostrophe depends upon the word you are making possessive.
- Singular possessive. Make a singular noun possessive by adding an apostrophe and an "s."
Example: Long's theory (2003) suggested...Note that singular nouns ending in "s" still take an apostrophe and an additional "s" (i.e., Jones's theory).
- Plural possessive (regular). Make a plural noun possessive by adding an apostrophe.
Example: The Nurses' Association published a code of ethics...
- Plural possessive (irregular). Make an irregular plural noun (e.g., "women" or "children") possessive by adding an apostrophe.
Example: The Akron Children's Hospital.
Common Apostrophe Errors
There are some common apostrophe errors that are easy to avoid. Do not use an apostrophe:
- When making a noun plural.
Incorrect: The studies' of Jones and Barnum...
Correct: The studies of Jones and Barnum... or Jones's and Barnum's studies...
- When making an acronym or a number plural.
Incorrect: CEO's of major corporations in the 1950's...
Correct: CEOs of major corporations in the 1950s...
- When constructing contractions. Apostrophes can also be used to create contractions (words like "can't" and "didn't"); however, contractions are rarely used in academic writing.
Incorrect: Walden University doesn't recognize Ground Hog Day as an official holiday.
Correct: Walden University does not recognize Ground Hog Day as an official holiday.
Note that this video was created while APA 6 was the style guide edition in use. There may be some examples of writing that have not been updated to APA 7 guidelines.