When Do You Use the Relative Pronoun “Which”? (Grammar Quiz)

Which “which” is which? Arrgh! Let’s get to the grammar behind this challenge. Start with a quiz.

Which of the following is/are correct in scientific writing?

  1. Most of the respondents were students. Which is understandable because the posters calling for volunteers were displayed mainly at our university.
  2. The interviewees, of which most were postgraduates, were first asked to complete a questionnaire.
  3. All questionnaires, through which we went twice, were complete and were included in this study.
  4. The questionnaire answers provided useful information on strategies of coping with different types of stress, which are summarized below.

These sentences contain relative clauses using the relative pronoun “which” to refer to something said earlier, but all four sentences are incorrect in formal scientific writing.

In (1), “which” begins a connective relative clause that refers to the whole previous clause. However, starting a sentence with a relative pronoun is informal. The formal version is “Most of the respondents were students, which is understandable because the posters calling for volunteers were displayed mainly at our university”. Note that the “Which” in the italicized question introducing the four sentences is a special question word (interrogative pronoun, not a relative pronoun).

Sentence (2) uses a non-defining (or non-restrictive) relative clause to add information about the “interviewees”. However, the personal relative pronoun is needed here in the object form (“whom”) because it follows a preposition. In addition, “most of whom” is more natural sounding in this case, as in “The interviewees, most of whom were postgraduates,…”.

Sentence (3) also contains a non-defining clause, but the phrasal verb “to go through” (meaning to examine) has an inseparable preposition. Hence, “went through” should be kept together, and the clause should be “which we went through twice”. However, “to go through” sounds informal, so the clause is better as “which we reviewed twice”.

It is unclear in (4) if “which” refers to the answers, information, strategies, types of stress, or the whole previous clause. It would be better to clarify with a new sentence (for example, “The most commonly cited strategies are summarized below”).

Quick Tip

Which of these alternatives is correct?

Our university has a new (1) stationary / (2) stationery shop.

Both words are pronounced the same, but (2) is correct because “stationary” is an adjective meaning motionless, and “stationery” is a noun referring to office supplies (note it has an “e” in its spelling, which is the same letter that starts “envelopes”).


Grammar and punctuation are among the top reasons for being rejected by a journal. To ensure the language in your manuscript is publication-ready you should have a native-English-speaking expert in your field edit for grammar, clarity, and accuracy of scientific expression.

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