Active vs Passive Voice: Tips and Suggestions to Help Improve the Clarity of Your Prose

Verbs in English have two voices: active and passive. Understanding how and when to employ active and passive voice in technical writing is critical to the clarity, effectiveness, and readability of your prose. Active voice is generally preferred to passive voice in technical writing, but who or what is performing an action will dictate which voice is used. Active and passive sentences differ in the structure of their subjects and the participle of their verbs. For example:

Active voice:


Passive voice:


Active voice is preferred in most contexts because a subject-verb construction is the clearest form of communication, where the subject is placed at the beginning of the sentence followed by an active verb. In the above example, the subject—the surgeon—performs the action—a heart transplant. Contrarily, the passive voice swaps the action’s target—the heart transplant—placing it first in the sentence. In a passive sentence, the subject is acted upon by a verb. There are instances in which passive voice can be effectively employed, such as when neutrality or diplomacy are necessary, or when the agent is intentionally omitted because it is either unnecessary, implied, or unknown. In the above example, the role of the surgeon is obvious enough to be omitted, leaving, “A heart transplant was performed today,” a perfectly coherent and direct sentence.

While active voice should typically outweigh passive voice in technical writing, a combination of both voices contextually is most effective. The important part is understanding why and when to use one voice over the other. For example, in a scientific paper, active voice is generally preferred when stating a hypothesis and presenting results, whereas the use of passive voice is often appropriate when discussing Materials and Methods. Meanwhile, the Introduction and Discussion often employ both active and passive voice.

While neither option is necessarily wrong, the below example illustrates how active voice makes the hypothesis clearer and more impactful:

Active voice: We hypothesize that vaccinated individuals are less likely to become infected than unvaccinated individuals.

Passive voice: The hypothesis was that vaccinated individuals are less likely to become infected than unvaccinated individuals.

One thing to keep in mind is that if one voice is overused, especially in technical writing, the prose itself can become stinted, redundant, or mechanical. It is best practice to interrupt extended passages that contain only one voice with its alternative where possible to avoid dullness. When writing, ask yourself whether it is beneficial for the reader to know the performer of the action. If it is, favor active voice. If not, passive voice may be the more effective choice.