One piece of writerly advice you often get is to “avoid the passive”. Quite why this sounds so sensible remains a mystery - not least because those dispensing it regularly ignore this supposedly “golden” rule themselves. And they ignore it for good reason - passives are a valuable communicative resource. That’s why we have them in the first place.

In other words, to prescribe a blanket rule like “avoid the passive” is to deny the meaning-making nature of grammar - it is no better than any other by-the-numbers approach. Just as you won’t necessarily improve a piece of writing by sticking in some fronted adverbials, you won’t necessarily improve it by eschewing passives. Instead, what matters is cueing students into the meaning potentials of this resource, so they can make effective use of it according to the writing at hand.

Before we can do that, however, we first need to know what the passive is.

What is the passive voice?

Essentially, the passive offers an alternative way of framing the same underlying set of “facts”. It does this by fiddling with the structure of certain verbs as follows:

1. The verb is expressed using a past participle form (e.g., “broken”, “hated”).
2. This verb is prefaced with a form of the auxiliary “be” (e.g., “is”, “were”).
3. An argument of the verb, which would otherwise appear after it, now appears before it, in subject position.
4. What would otherwise be the subject of the verb gets demoted, such that it can either be omitted entirely or expressed as part of a preposition phrase with “by” as its head.
    

The upshot of this fiddling is that English gives us the choice of presenting the same proposition in two ways: the “unfiddled” active version, and the alternative passive version.

For example:

Cats eat mice. [active version]

Cats are eaten by mice. [passive version]

When to use the passive

With that in mind, here are three ways the passive can come in handy.

1. De-emphasising an element

Perhaps the most striking property is de-emphasising what might otherwise be the subject of the clause. In the classic case, this can be an avoidance strategy, a way of hiding the agent and escaping any blame. Hence, every politician’s favourite passive: “Mistakes were made”.

But it’s more fundamental than that: in allowing us to change what appears as the subject of a sentence, the passive allows us to shift what that sentence is about. This is one reason it’s more common in science writing, where we have more interest in the experiments themselves, for example, than who conducted them. Consider, for example, the difference between the (a) and (b) versions below:

(a) We implemented three different interventions to test the hypothesis. [active version]

(b) Three different interventions were implemented to test the hypothesis. [passive version]
 

2. Managing the flow of information

Crucial to creating a successful text is the way we manage the flow of information from sentence to sentence. English partly does this by distinguishing between information that is relatively familiar within the current text from information that is newer. Most importantly, it also tends to do so by placing the more familiar information earlier in the clause. Accordingly, the passive can be a handy tool for managing this distinction through its capacity to manipulate what appears in subject position. Consider, for example, the difference between the (a) and (b) versions below, where “an unknown group” represents the new information and “it” the familiar information:

(a) The explosion happened at 11am. An unknown group caused it. [active version]

(a) The explosion happened at 11am. It was caused by an unknown group. [passive version]
 

3. Managing the weight of a sentence

All things being equal, English prefers “heavier”/“longer” syntactic units to come at the end of a clause. They’re just easier to process that way. Again, this is where the passive can be handy, through its capacity to move what might otherwise be a heavy subject into a later “by”-phrase. Consider, for example, the difference between the (a) and (b) versions below:

(a) The dog that chased the cat that harried the mouse ate the bone. [active version]

(b) The bone was eaten by the dog that chased the cat that harried the mouse. [passive version]
 

How to teach the passive

• Take some writing from a number of different genres (e.g., a novel, a news report, an academic essay). Either have your students identify several examples of the passive from each, or have the examples highlighted for them. Get them to discuss what the effect of each passive might be in the context of that piece of writing. Have them discuss whether they could express the same meaning without using the passive.
• Take any passage of writing, and number each sentence. Ask each student to select a sentence of their own choosing. If it uses the passive voice, get them to rewrite it without using the passive; if it doesn’t, get them to rewrite it using the passive. Get them to consider how the two sentences differ in terms of the meanings they evoke. In their view, do the different versions improve or worsen the text?
   

Ian Cushing teaches English linguistics at University College London and is a doctoral researcher in applied linguistics at Aston University, working on grammar teaching at secondary school level. Mark Brenchley is an associate research fellow at the Centre for Research in Writing at the University of Exeter. He works on the Growth in Grammar project, which is seeking to understand what grammatical development in student writing actually looks like.

Further reading:

•  Biber, D., Conrad, S., & Leech, G. (2002) Student Grammar of Spoken and Written English. Harlow: England [pp.166-174].
• Crystal, D. (2004) Making Sense of Grammar. Harlow: Pearson [Chapters 22, 70-72]