Passive Voice

The passive voice is a grammatical construction (specifically, a "voice"). The noun or noun phrase that would be the object of an active sentence (such as Our troops defeated the enemy) appears as the subject of a sentence with passive voice.

Learning the written "voice"

Many students have been told by one professor or another to not use the passive voice. 

In English grammar, the passive voice is a construction in which the object (the noun receiving action) of a verb actually appears before the verb itself. And the subject may disappear altogether, or else come after the verb. 

This is different from the normal subject-verb-object construction of most English sentences. 

The passive voice definitely has its distinctive purposes. 

However, its use is often discouraged due to the fact that it can lead to ambiguity and lack of accountability, with no information being given about who is actually responsible for an action. 

Passive voice and proper grammar

Here is an example of the passive voice being used correctly within a sentence. 

"When the people awakened in the morning, all the radio stations were announcing the news that the enemy had been defeated."

In this sentence, "the enemy had been defeated" is in the passive voice. The subject of the verb (i.e. who defeated the enemy) has been omitted from the sentence. 

Now, here is an example of the passive voice being used incorrectly in a sentence. 

"The student had been written by the paper, but the professor believed that he did not spend enough time on doing good research." 

In this sentence, the words student and paper should be switched around, because the passive construction follows the object-verb-subject pattern.   

Now, here are a couple rules you can follow, in order to make sure you are using the passive voice in a proper way. 

1. When using the passive voice, the object of the verb always comes before the verb. Instead of saying "John ate the food", you would say the "Food was eaten by John". The subject and object thus switch places, and the main verb is changed into a participle form. The meaning conveyed will be exactly the same, but the basic syntax of the sentence will be changed. 
2. The passive voice allows you to actually drop the subject of the sentence altogether. For example, if you say "The food was eaten", there is no indication of who has actually eaten the food. The passive voice can thus be useful either when you don't know the subject of an action, or when you want to focus primary attention on the action itself and not on the subject.  

Passive voice and academic writing

Within academic contexts, the passive voice is usually discouraged by professors, on the grounds that it introduces ambiguity and lack of clarity into argumentation. In particular, the passive voice tends to reduce accountability, by failing to indicate who exactly has affirmed or defended a given point.

For example, the phrase "It has been said that" is in the passive voice, and such a phrase would give no information at all about the nature or credibility of the persons doing the speaking. 

Interestingly, though, this prohibition of the passive voice in academic writing is contradicted by a parallel prohibition on the use of the first person ("I") in such writing. This is contradictory due to the fact that the subject of many assertions would in fact be the writer herself. The passive voice would enable to writer to omit herself as subject from the sentence; but then, this is frowned upon as well. Taken together, this accounts for the prevalence of awkward constructions, where terms like "the present essay" or "the present writer" becomes the subject various sentences.