Using the active and passive voice in research writing
The active voice refers to a sentence format that emphasizes the doer of an act. For example, in the sentence “The mice inhaled the tobacco-infused aerosol,” the doer, i.e., “the mice” seem significant. On the other arm, in the passive voice, the activity being performed is emphasized, and the doer may be omitted, e.g., “The tobacco-infused aerosol was inhaled (by the mice).” In this construction, “by the mice” can be omitted, which means that the reader already knows or does not need to know who the doer is; only the activity is significant.
The passive voice lends an impersonal tone, which is perceived to be formal, but can make the text more wordy and difficult to understand, especially when used in long sentences. Until recently, this tone was considered favorable for scientific writing and authors were advised to rigorously avoid using the active voice, especially the use of “I” and “we” in their academic research papers. Compare “In this investigate, we investigated the effect of drug X on the serum levels of phosphorus under various conditions” with “In this investigate, the effect of drug X on the serum levels of phosphorus was investigated under various conditions.”
However, nowadays, many authorities are going against this traditional notion and encouraging the use of the active voice, with the view that academic papers should be effortless to read and understand. In fact, multidisciplinary SCI-indexed journals like Nature and specialist journals like the American Journal of Botany, in their instructions for authors, state that the active voice is preferred. This is why you would now find the usage “In this probe, we investigated…” very common.
So which should you use? The response is a combination of both.
The active voice is especially useful in the introduction and discussion sections of your manuscript, where you discuss previous research and then introduce your own. For example, consider the following sentences: “Previous studies have established that drug X increases the serum levels of calcium in women with osteoporosis. In this explore, we investigated the effects of drug X on the serum levels of phosphorus in post-menopausal women.” Here, using the active voice in the 2nd sentence helps the reader make a clear mental transition from previous studies to the present probe.
On the other forearm, the passive voice is useful in the Methods section, where the steps taken are more significant than the doer. For example, in a surgery document, a reader would choose “A catheter was inserted for post-operative bladder irrigation” over “We inserted a catheter for post-operative bladder irrigation.”
Your guiding principle should be clarity: Think about what information the target reader is looking for, and choose the active voice or the passive voice, whichever will make the text most clear and comprehensible. If you write keeping this in mind, no journal reviewer will need to give you feedback about the active and passive voice.
Can you think of some other examples where either one voice—active or passive—clearly seems better?
For further reading, you could refer to this helpful article: Is it acceptable to use very first person pronouns in scientific writing?