Explanation I use in comments on student papers:
Passive voice, as it is called, should be used rarely; active voice is far more effective. A sentence such as the following is passive voice: “Pictures are used in the novel in an interesting way.” By contrast, active voice would be: “The author uses pictures in her novel in an interesting way.” (Even better would be the choice of a verb that lends more precision, vividness, or activity to the general verb “use” here–e.g., “The author embeds pictures in her novel in an interesting way.”) Here is another example: “The sun is compared to a round, golden coin” versus “the poet compares the sun to a round, golden coin.”
Not only does passive voice create a dull, flat, anonymous effect, but it often forces a writer into awkward, contorted sentence structures. If you use active voice, you’ll be closer to your natural speaking voice.
In addition, passive voice sometimes has the effect of hiding crucial information about agency: who or what is performing the action of a verb. For example, if one were writing an essay about surveillance society in the digital age, a passive voice sentence like the following is problematic: “Much data about every private citizen today is collected in databases.” Collected by whom–companies, the government, the military?
Version 2
Passive voice, as it is called, should be used rarely; active voice is far more effective. Not only does passive voice create a wooden, inert, or bureucratic tone (e.g., “it was found that,” by contrast with active voice: “they found that,” “we found that,” “researchers found that,” etc.) but it often hides key informaton (e.g., who is performing the action indicated).
