Chalk it up to bad influence from autocorrect, but one error that’s becoming more and more common is the incorrect spelling of who’s and whose. Still, although these homophones (words that sound the same but have different meanings) look tricky enough, they’re actually quite easy to sort out. Who’s with me?
Who’s is a contraction, a shortened form of the phrase Who is. It is not a possessive pronoun. That’s all there is to remember! Always follow this rule: if you cannot substitute who is, you should not be using who’s.
Example A: Who’s coming over this evening?
Expanded Example A: Who is coming over this evening? Expanding the contraction shows that Who’s was the correct word to use.
Incorrect Example B: I am trying to find out who’s diary this was. This is incorrect because substituting who is doesn’t make sense: “who is diary this was”?
Corrected Example B: I am trying to find out whose diary this was.
A note: sometimes, in very informal writing like dialogue, who’s is used as a contraction for who was. The same general rule applies, but I recommend avoiding using the contraction at all in this case. Your reader may be confused about whether you’re using present or past tense.
Whose, on the other hand, is a possessive pronoun. Like all possessives, it implies ownership or belonging. It is not a contraction and never stands in for who is. If you can substitute who is, then use the contraction instead.
Example C: She met a man whose father was a spy. Here, the possessive form whose is correct because it implies belonging (the spy was the man’s father).
Incorrect Example D: I don’t know whose in my class this year. This is incorrect because it is supposed to mean who is, and whose is not a contraction for who is.
Corrected Example D: I don’t know who’s [who is] in my class this year.
This example combines both words:
Example E: The student whose paper won the award is the same person who’s running for student council. Here, it’s whose paper because there is a possessive relationship (and who is paper doesn’t make sense), and who’s running because you can substitute who is.
Whos is not a word. Unless you’re talking about the Whos down in Whoville, never use it.
Sorting out who’s and whose is actually fairly simple. Next week we’ll talk about some trickier questions, like when and how you should use whose (hint: it’s not what you think!).
Christina M. Frey is a book editor, literary coach, and lover of great writing. For more tips and techniques for your toolbox, follow her on Twitter (@turntopage2) or visit her blog.