Active Voice vs. Passive Voice

In an active voice sentence, the subject acts on the object.

In a passive voice sentence, the subject is acted upon by the object.

Example 1

The following is a simple active voice sentence:

• Active: Nomar hits the ball.

In the previous sentence:

• "Nomar" is the subject.
• "hit" is the verb.
• "the ball" is the object.

Notice that the subject acts on the object.

(Don't panic--this course almost never dives down into grammar. We're just taking a quick plunge.)

Now we'll convert that same sentence into passive voice:

• Passive: The ball is hit by Nomar.

Notice that the object (the ball) is acted upon by the subject (Nomar). Furthermore, the sentence has expanded from four words to six words.

Example 2

• Active: The browser displays GIF files.
• Passive: GIF files are displayed by the browser.

Example 3

• Active: Telephones connect two or more parties.
• Passive: Two or more parties are connected by telephones.

Example 4

• Active: I measured barometric pressure.
• Passive: Barometric pressure was measured.

The preceding passive voice example omits a subject. Who measured barometric pressure?

Why is Passive Voice Evil?

Passive voice is generally inferior to active voice because passive voice:

• lengthens sentences.
• reduces clarity.
• often omits the subject.
• is much harder for foreign readers to understand. (Many non-native English speakers don't get that far in their English lessons.)

But, Scientists Use Passive Voice in Lab Reports All the Time

Many scientists write lab reports in passive voice. Scientists do this because of:

• Tradition.
• The mistaken belief that omitting pronouns makes lab reports sound more objective.

I believe that this tradition should end as soon as possible. Let clarity be the guiding principle. Acknowledge the actor in every sentence. Outside of Harry Potter, microscopes do not see; humans see through microscopes.

If you absolutely cannot bring yourself to use pronouns in write-ups, here are some alternate subjects:

• "The authors"
• "The study"
• "The lab team"
• "Algernon"

When is Passive Voice Okay?

Occasional passive voice is okay; for example, when you'd prefer to stress the object. For example, if the topic is "Hurricanes," then the following active voice sentence is appropriate:

• Active: Hurricanes seldom hit New York City.

However, if the topic is "New York City," then a passive voice sentence such as the following might make more sense:

• Passive: New York City is seldom hit by hurricanes.

Sometimes, you use passive voice to intentionally obscure the subject:

• Passive: "Mistakes were made."
• Passive: "Hmm, the last candy bar has been taken."

You should usually avoid the preceding in technical or scientific writing because it is essential that the reader understand who is doing what to whom.

Sometimes, you sprinkle in a passive voice sentence for the sake of variety to break up the monotony of a string of active voice sentences. We'll revisit sentence variety later on in the course.