Active and Passive Voice

Strong, precise verbs are fundamental to clear and engaging academic writing. However, there is a rhetorical choice to be made about whether you are going to highlight the subject that performs the action or the action itself. In active voice, the subject of the sentence performs the action. In passive voice, the subject of the sentence receives the action. Recognizing the differences between active and passive voice, including when each is generally used, is a part of ensuring that your writing meets disciplinary conventions and audience expectations.  

Traditionally, writers in STEM fields have used passive voice because the performer of an action in a scientific document is usually less important than the action itself. In contrast, arts and humanities programs have stressed the importance of active voice. However, these guidelines are fluid, and STEM writers are increasingly using active voice in their writing. When in doubt, consult academic publications in your field and talk to your instructor – doing these things should give you a good sense of what’s expected.

Active voice emphasizes the performer of the action, and the performer holds the subject position in the sentence. Generally, you should choose active voice unless you have a specific reason to choose passive voice (see below for those instances).  

e.g., Participants (1) completed (2) the survey and returned it to the reader. 

1. Subject (performer of the action)

2. Verb (the action completed by the subject)

Passive voice emphasizes the receiver of the action, and the subject of the sentence receives the action. When using passive voice, the performer of the action may or may not be identified later in the sentence. 

e.g., The survey was completed. 

In the above sentence, the people who performed the action (those who completed the survey) are not mentioned. 

e.g., The survey was completed (1) by participants (2) and returned to the researcher. 

1. Passive voice does not highlight the performers of the action (the participants); instead, the action of completing the survey is highlighted 

2. The prepositional phrase by participants identifies the performers of the action, but it does so only after the action itself has been identified

One popular trick for detecting whether or not your sentence is in passive voice is to add the phrase by zombies after the verb in your sentence; if it make grammatical sense, your sentence is passive. Passive: e.g., The trip was taken [by zombies]. Not passive: e.g., Mandy taught the class [by zombies]. 

When to Choose Passive Voice 

Deciding whether or not you should use passive voice depends on a number of factors, including disciplinary conventions, the preferences of your instructor or supervisor, and whether or not the performer of the action or the action itself is more important. Here are some general guidelines to help you decide when passive voice is appropriate: 

• The performer is unknown or irrelevant 

e.g., The first edition of Freud’s The Interpretation of Dreams was published in 1900. 

• The performer is less important than the action 

e.g., The honey bees were kept in a humidified chamber at room temperature overnight. 

• The recipient of the action is the main topic 

e.g., “We wish to suggest a structure for the salt of deoxyribose nucleic acid (D.N.A.) (1). A structure for D.N.A. has already been proposed by Pauling and Corey” (Watson and Crick, 1953) (2).

1. Active voice (where the performers want to be highlighted) 

2. Passive voice (where the performers are identified, but are noted secondarily to the action itself)

Rhetorical choices often have an ethical dimension. For instance, passive voice may be used by people, organizations, or governments to obscure information or avoid taking direct responsibility. If someone says “the money was not invested soundly,” the decision to not identify the performer of the action (“the accountant did not invest the money soundly”) may be a deliberate one. For this reason, it is crucial that we question the choices we make in writing to ensure that our choices result in correct, clear, and appropriate messaging.

If you are proofreading in order to convert passive voice to active voice in your writing, it is helpful to remember that: 

Active = Performer of Action + Action 

Passive = Action itself (may or may not identify the performer afterwards) 

Here are some sample revisions: 

1. Passive voice 

2. Active voice

e.g., It is argued that... (1)

e.g., Smith argues that... (2)

e.g., A number of results were shown... (1)

e.g., These results show... (2)

e.g., Heart disease is considered the leading cause of death in North America. (1)

e.g., Research points to heart disease as the leading cause of death in North America. (2)