Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
VOICE 2: ACTIVE, PASSIVE
Voice is a grammatical feature of English verbs, which expresses a particular relationship between the subject of the sentence and its direct object, if any. In John caught the ball, the verb caught is in the active voice: John did to the object ball what the verb caught expresses. In The ball was caught by John, the verb was caught is in the passive voice: the subject of this sentence is ball, and the action of the verb was caught indicates what happened to it but requires a prepositional phrase, by John, to let us know who did it. Active voice makes subjects do something (to something); passive voice permits subjects to have something done to them (by someone or something). Some argue that active voice is more muscular, direct, and succinct, passive voice flabbier, more indirect, and wordier. If you want your words to seem impersonal, indirect, and noncommittal, passive is the choice, but otherwise, active voice is almost invariably likely to prove more effective.
