Passive voice, as defined by the Lexico’s Dictionary, is “the voice used to indicate that the grammatical subject of the verb is the recipient (not the source) of the action denoted by the verb.” As opposed to active voice, passive voice is considered bad writing tone. If you are unsure how to tell the difference between the passive voice and the active voice, please go to a wonderful article Active Verbs vs. Passive Verbs by Dennis Jerz of Seton Hill University. In this post, I am telling about why you should avoid passive voice, and when you can use it.
As described by Stephen King in his On writing, passive verbs in writing are for cowards. When the writer intentionally avoids the active doer, he (or she) is literally affraid of the responsibility that this active doer would take. Passive voice is not wrong, and, if used wisely, can emphasize important points or perform other specific tasks. In most cases, however, you must not use passive voice in your writing, regardless of whether you are writing a technical report or a narrative.
Negative features of passive voice
Passive voice accepts ignoring or providing no information about the doer of the action. Consider an example: the car was driven by a girl. In this sentence, the car is the subject, “was driven” is the predicate (with a linking verb to be), and the girl -- the actual doer of the action (driving) -- is the object. And the object, is the secondary part of sentence, which can be kindly removed without harming the main idea of the sentence. Thus, with passive voice, we almost ignore the doer (the person or thing taking action).
Another feature of passive voice sentences is that they are weak, vague, and ineffective. Consider revising the example above to the girl was driving the car. This statement is firm, strict, and strong. The writer takes responsibility and gives the girl the authority to drive, -- not the car to be driven. Therefore, take responsibility, write firmly, and use active voice.
When passive voice is acceptable
There are cases, when you should use passive voice. The most common case is to wilfully remove the doer for a definite reason. For example, with an intention to conceal the identity of the doer, the IT specialist may respond to the police, “the files had been deleted.” In this case, the speaker wilfully ignores the doer of the action, because he wants the doer to stay in the shadow. Therefore, use passive voice only when there is a valid reason to remove the doer from the statement.