Generally, try to use the active voice whenever possible. Passive voice sentences often use more words, can be vague, and can lead to a tangle of prepositional phrases.
Active vs. passive voice
In a sentence written in the active voice, the subject of sentence performs the action. In a sentence written in the passive voice the subject receives the action.
Active: The candidate believes that Congress must place a ceiling on the budget.
Passive: It is believed by the candidate that a ceiling must be placed on the budget by Congress.
Active: Researchers earlier showed that high stress can cause heart attacks.
Passive: It was earlier demonstrated that heart attacks can be caused by high stress.
Active: The dog bit the man.
Passive: The man was bitten by the dog.
Converting sentences to active voice
Here are some tips and strategies for converting sentences from the passive to the active voice.
- Look for a “by” phrase (e.g., “by the dog” in the last example above). If you find one, the sentence may be in the passive voice. Rewrite the sentence so that the subject buried in the “by” clause is closer to the beginning of the sentence.
- If the subject of the sentence is somewhat anonymous, see if you can use a general term, such as “researchers,” or “the study,” or “experts in this field.”
When to use passive voice
There are sometimes good reasons to use the passive voice.
To emphasize the action rather than the actor
After long debate, the proposal was endorsed by the long-range planning committee.
To keep the subject and focus consistent throughout a passage
The data processing department recently presented what proved to be a controversial proposal to expand its staff. After long debate, the proposal was endorsed by . . . .
To be tactful by not naming the actor
The procedures were somehow misinterpreted.
To describe a condition in which the actor is unknown or unimportant
Every year, thousands of people are diagnosed as having cancer.
To create an authoritative tone
Visitors are not allowed after 9:00 p.m.