Passive can be an ambiguous term in writing because it can refer to a grammatical construction, but it can also refer to the way a sentence “feels,” usually meaning something like “flat” or “abstract” or “devoid of clear narrative action.” Voice is similarly ambiguous: it can also refer to the general “feel” or “style” of the writing (as in the advice to find your own voice), or it can be used in a more technical sense when applied to a verb to indicate whether the subject of a sentence acts or is acted upon. In this section, we will focus on the technical sense as we discuss active and passive voice.

You’ve probably heard of the passive voice, perhaps in a comment from a teacher or in the grammar checker of a word processor. In both of these instances, you were probably guided away from the passive voice. Why is this the case? Why is the passive voice so disliked? After all, it’s been used three times on this page already (four times now). The first possible answer is that using the passive too frequently can obfuscate the central narrative of your writing. A related answer is that teachers issue a blanket warning against it because students need a relatively sophisticated grasp of the exceptions to the rule in order to use the passive effectively. What might be too much information for a schoolchild, however, constitutes useful information for a college-level writer. There are certainly instances where the passive voice is a better choice than the active.

One way to think about the difference between these two grammatical voices is that an active voice sentence is written in the form of “A does B,” for example, “Carmen sings the melody.” A passive voice sentence is written in the form of “B is done by A,” for example, “The melody is sung by Carmen.” Both constructions are grammatically correct; the difference is one of voice. You might notice that this definition works for transitive verbs (verbs that take a direct object); only transitive verbs can take the passive voice.

Let’s look at a couple of more complicated examples of the passive voice:

• I’ve been hit! (or, I have been hit!)
• When Jasper’s car was struck from behind, he was thrown from it.

In these sentences, the grammatical subject of the sentence is not the person (or thing) performing the action (represented by a verb). “I,” the subject of the first example, did not perform the action of hitting. Jasper’s car, the grammatical subject in the second, did not perform the action of striking from behind. Unlike the sentence about Carmen’s singing, where even the passive version lets us know who is doing what through the phrase “by Carmen,” these sentences don’t tell us who or what causes the action. Put another way, the passive voice can “hide” who performs an action. Despite these sentences being completely grammatically sound, we don’t know who hit “me” or what struck the car. This issue is why the passive voice can obfuscate the clear narrative of a piece of writing – imagine that you are “I’ or you are “Jasper” – you probably very much want to know who or what hit you, and who or what struck your car! Not being provided with that information leaves you with an unclear (and probably deeply unsatisfying) narrative. It also puts pressure on context to make things clear for the reader – we can’t tell whether the first example here means “Gunfire hit me!” or “Jimmy hit me!”

Grammatically, the passive is created using a double structure. Both parts must be present in order for a sentence to be in the passive voice. The passive takes a form of the verb to be (e.g., the melody is sung; it was struck from behind) as an auxiliary verb, paired with the past participle form of the main verb (e.g., the melody is sung; it was struck from behind). Remember that to be conjugates irregularly. Its forms include am, are, is, was, were, will be, is being, will have been, and have been.

Although the past participle is a past tense form of a verb, notice that in a passive construction, the verb’s tense is not determined by that past participle, but rather by the tense of the auxiliary, to be: “I covered the story” is in the past tense in this active sentence because the past form of “to cover” is “covered;” however, “I am covered by health insurance” is in the present tense, despite also containing the past participle, because the tense is determined by the auxiliary verb in this passive construction; i.e., “am.” Compare that tense to “I was covered,” “I will be covered,” or “I have been covered:” all different tenses, but all passive. Don’t confuse the passive voice with the past tense.

Furthermore, be aware that English sometimes uses the same form for the past participle and for adjectives. Consider the sentence, “I was scared.” Is this a passive construction (“I was scared by the explosion”) or an adjective (“I was scared; I was anxious”)? Thinking about how you want the word to function grammatically will help you present it to your reader in its most appropriate form, and will also prevent you from launching an ill-fated witch-hunt after anything (like adjectives and the past form of verbs) that so much as looks like a past participle.

Because to be has other uses than just creating the passive voice, we need to be careful when we identify passive sentences. It’s easy to mistake a sentence like “She had been failing” or “He is educated” for a passive sentence. However, in “She had been falling,” had been simply indicates that the action took place in the past. In “He is educated,” is is a linking verb. If there is no “real” action taking place, is is simply acting as a linking verb.

Usage

Passive constructions can produce grammatically tangled sentences such as this:

Groundwater flow is influenced by zones of fracture concentration, as can be recognized by the two model simulations (see Figures 1 and 2), by which one can see . . .

The sentence is becoming a burden for the reader, and probably for the writer too. As often happens, the passive voice here has smothered potential verbs and kicked off a runaway train of prepositions. But the reader’s task gets much easier in the revised version below:

Two model simulations (Figures 1 and 2) illustrate how zones of fracture concentration influence groundwater flow. These simulations show . . .

To revise the above, all we did was look for the two buried things (simulations and zones) in the original version that could actually do something, and make them the grammatical subjects of the sentence by placing them in front of active verbs. This is the general principle to follow as you compose in the active voice: place concrete nouns that can perform work in front of active verbs. In other words, tell your reader that most interesting narrative information – who does what.