Guideline. Unless you have a good reason for doing otherwise, express verbs in the active rather than the passive voice.
A verb is in the active voice when its subject is also the performer of the action. It is in the passive voice when its subject is something or someone other than the doer of the action. While there is nothing grammatically wrong with either construction, expressing verbs in the active rather than the passive voice usually produces sentences that are smoother and more concise.
- The emperor called our office today while you were at the baths. (Called is in the active voice because its subject, emperor, is the doer of the action.)
- Our office was called this morning by the emperor. (Was called is in the passive voice because its subject, our office, did not perform the action. The emperor did.)
Its drawbacks notwithstanding, the passive voice has several legitimate--and even preferable--uses. When a verb is expressed in the passive voice (as it was just then), the emphasis shifts from the doer of the action to the object of the action. Here are three reasons you might want this shift to occur:
- Emphasis. Use the passive voice when the intent of your sentence is better served by giving more emphasis to the receiver of the action than to the doer of the action.
- The plan to relocate the employee hot tub to the warehouse was met with stiff opposition. (In this sentence, the plan and the fact that it met with stiff opposition are more important than the identity of the people opposing it.)
- I will not be ignored. (Whoever might be doing the ignoring in this situation is less important than the person who doesn't want to be ignored.)
- Tact. Use the passive voice to soften the impact of a rejection.
- It was felt [rather than we felt] that your proposal did not sufficiently meet our needs. (Not mentioning the doer of the action takes some of the sting away from the rejection.)
- Convenience. Use the passive voice when you want to avoid using "you."
- The form is to be filed immediately. (The passive voice is used here to avoid the use of you, as in "You should file the form immediately.")
Source: Grammar for Smart People by Barry Tarshis.