A common problem with pronoun case is deciding whether to use who or whom. Even when traditional grammar requires whom, many Americans use who instead, especially in speech. Nevertheless, you should understand the difference between who and whom so that you can make informed choices in situations such as formal college writing that may call for the use of whom (or whomever) in the objective case.

Two particular situations lead to confusion with who and whom: when they begin a question and when they introduce a dependent clause.

Choosing who or whom in questions

You can determine whether to use who or whom at the beginning of a question by answering the question using a personal pronoun. If the answer is a subject pronoun, use who; if it is an object pronoun, use whom.

I think she wrote the story. She is subjective, so who is correct.

I visited them. Them is objective, so whom is correct.

Using who, whoever, whom, and whomever in dependent clauses

The function a pronoun serves in a dependent clause determines whether you should choose who or whom, whoever or whomever—no matter how that clause functions in the sentence. If the pronoun acts as a subject or subject complement in the clause, use who or whoever. If the pronoun acts as an object, use whom or whomever.

Whoever is the subject of the clause whoever wants to use it. (The clause is the object of the preposition to, but the clause’s function in the sentence does not affect the case of the pronoun.)

Here, whom is the object of the verb had expected in the clause whom she had expected.

If you are not sure which case to use, try separating the dependent clause from the rest of the sentence. Rewrite the clause as a new sentence, and substitute a personal pronoun for who(ever) or whom(ever). If the pronoun is in the subjective case, use who or whoever; if it is in the objective case, use whom or whomever.

The minister glared at (whoever/whomever) made any noise.

Isolate the clause whoever/whomever made any noise. Substituting a personal pronoun gives you they made any noise. They is in the subjective case; therefore, The minister grimaced at whoever made any noise.

The minister smiled at (whoever/whomever) she greeted.

Isolate and transpose the clause to get she greeted whoever/whomever. Substituting a personal pronoun gives you she greeted them. Them is in the objective case; therefore, The minister smiled at whomever she greeted.

Ignore such expressions as he thinks and she says when you isolate the clause.