Why does this matter?
In the examples listed above, the passive voice versions are not especially long-winded, yet if you re-examine them you will notice that they feature more words than their respective active versions. This is of great relevance to you as science writers because it is very important that you always try to communicate things as concisely as possible. When you start to write more complex sentences, the difference in word count can be significant when you compare the active and passive voice versions, and this is important in a setting in which waffly, vague statements are always your enemy.
Along with a lack of conciseness, ambiguity (being vague) is the other unwanted attribute that comes with the use of passive voice sentences. For example, consider the following active and passive versions of a sentence that might appear in the methods section of your lab report:
3A:Professor Robertskept the mice in their cages for three weeks. He then releasedthem into the wild and recaptured them three weeks later.
3P:The mice used in this experiment were kept in their cages for three weeks before they were released and then recaptured after they had spent three weeks in the wild.
Note firstly that the active voice version features 24 words in comparison to the 30 in the passive one, yet, importantly, the active version explains exactly what happened and who did what, whereas the passive one leaves these specific details out.
But, sometimes you should use the passive voice…
You might be developing the impression that using the active voice is always preferable, but this is not the case. Using the active voice is generally preferable because it tends to help you write more concise sentences and makes use of stronger verb forms. However, using the passive voice is acceptable in many situations, and is actually preferable when:
1) You want to be purposefully vague.
- For example: ‘The study was compromised due to a methodological error,’ rather than ‘Mike made an error, which compromisedthe study.’
2) You don’t know the identity of the ‘doer’.
- For example: ‘The cave paintings were made over 5,000 years ago,’ rather than ‘Someonemade the cave paintings over 5,000 years ago.’
3) The ‘doer’ is not important.
- For example: ‘An experimental traffic system will be trialled in British Columbia,’ rather than ‘RoadCorps will trial an experimental traffic system in British Columbia.’
4) You are referring to a general truth.
For example: ‘Rules were made to be broken,’ rather than ‘The person who madethese rules made them to be broken.’
Active vs. Passive Voice
Active Voice – If a sentence is written using the active voice, the subject of the sentence performs the action expressed by the verb.
- Example: John wrote the essay.
- Example: Christine plays basketball.
Passive Voice – If a sentence is written using the passive voice, an action is performed upon the subject of the sentence.
- Example: The essay was written by John.
- Example: Basketball is played by Christine.
The active voice is generally preferred in academic writing, so it should be used throughout most essays. Using the active voice tends to make sentences more clear and less wordy. This becomes particularly important in longer sentences. Using the active voice allows for writing to be less wordy, and this makes for better writing.
There are exceptions when the passive voice is used, such as when the noun performing the action is obvious, unimportant, or unknown. This is because using the passive voice draws attention to the action itself rather than the noun performing the action. For instance, the passive voice is often used in scientific writing, such as in lab reports, where the emphasis is placed on the action.
- Example: “A successful operation was performed” may be preferable to “The doctor performed a successful operation” because it highlights the operation itself, rather than the doctor.
Either way, all writers should be aware of the differences between the active voice and the passive voice and use the appropriate one for any given assignment. When in doubt, use the active voice.