by Tyler Krupa
I don’t think that I’m revealing a big grammar secret by letting you know that the possessive of a singular name is formed by adding an apostrophe and an s (e.g., Smith’s, 2012, study). But although this rule seems straightforward, one thing that trips up many writers is how to form possessives when the name being used ends with an s. For example, should you use “Adams’ (2013) work” or “Adams’s (2013) work”?
Per APA Style, the answer is that the possessive of a singular name is formed by adding an apostrophe and an s, even when the name ends in s (see p. 96 in the sixth edition of the Publication Manual). Therefore, in the example above, the correct usage would be “Adams’s (2013) work.” Although this presentation may look awkward to some writers, the rule for forming the possessive does not change just because the name ends in s.
However, it is important to note the following exception to this rule: You should use an apostrophe only with the singular form of names ending in unpronounced s (see p. 97 in the Publication Manual). Therefore, if you were writing a paper about the philosopher Descartes, to form the possessive with his name, you would need to just add an apostrophe (e.g., Descartes’ theory).
To help illustrate these guidelines, let’s look at a few more examples of properly formatted possessives:
Sigmund Freud’s method
Charles Dickens’s novels
François Rabelais’ writings (note that Rabelais ends with an unpronounced s)
We hope these examples clear up this point of possible uncertainty. Still have questions? Leave us a comment.