In general, you can make your writing more persuasive, clear, and concise by using the active voice rather than the passive voice. There are instances, however, when the passive voice is preferable to the active voice, as discussed below.
What are the Active and Passive Voices?
Essentially, a verb is active when its subject performs the action. A verb is passive when its subject is acted upon by an outside agent rather than doing the action. You can identify passive voice by finding a sentence that uses some form of the verb to be (am, is, was, were, being, been) along with a past participle (a verb form ending in -ed, -en) or some other verb form. The preposition by may follow the to be verb and past participle or it can be implied, as illustrated below:
Passive: The data were confirmed.
Active: Three independent scholars confirmed the data.
Passive: I was made a better scholarly author by writing regularly.
Active: Writing regularly has made me a better scholarly author.
Passive: She was had by the con artist.
Active: The con artist had her.
What’s Wrong with the Passive Voice?
The main problem with passive sentences is that they leave readers unsure of who or what is causing the action. Passive sentences tend to be wordy, dull, and confusing. One of the best ways to create a vigorous voice is to avoid passive sentence constructions. Use of the passive voice tends to create awkward pronoun references and faulty modification. For example, when readers come to the pronoun it in the following journal excerpt they have no way of knowing if the it refers to rational behavior or purpose–the subjects of the previous clauses:
The purpose of this paper will be to define the rational behavior of an academic writer. Once rational behavior is defined, it will be shown that this behavior is consistent with currently observed trends in academic publishing.
Actually, neither of these referents makes much sense because the real referent is the missing subject–the “I” of the author. Nine times out of ten, you should transform passive sentences into active ones. Surprisingly, however, the use of the passive voice is endemic in academic discourse–particularly in the methods section of quantitative research reports. Notice how the revision to the following excerpt from an essay in Philosophical Magazine becomes more vigorous and concise once it is transformed into the active voice:
Passive: In this paper the contrast of dislocations in icosahedral quasicrystals is discussed in the framework of the quasilattice model and on the basis of the kinematical theory of electron diffraction. Since, at present, little is known about the structure of quasicrystal dislocations, our treatment is restricted to the derivation of conditions under which the diffraction contrast vanishes and the dislocations become invisible. Some basic structural properties of quasilattices and quasilattice dislocations are first discussed.
Active: We discuss the contrast of dislocations in icosahedral quasicrystals in the framework of the quasilattice model and on the basis of the kinematical theory of electron diffraction. We restrict our treatment to the derivation of conditions under which the diffraction contrast vanishes and the dislocations become invisible because we know little about the structure of quasicrystal dislocations. First we discuss some basic structural properties of quasilattices and quasilattice dislocations.
When Is the Passive Voice Preferable to the Active Voice?
While the passive voice strangles the life from most academic discourse, it does have some legitimate uses. For example, if you needed to fire someone for inadequate work, you would probably want to say, “The decision has been made to let you go” rather than, “I have decided to fire you.”