non fiction - When *should* I use passive voice?

Is there ever a good time to use passive voice in nonfiction?

Answer

You can effectively use passive voice when the action is more important than the actor.

For example, if you were writing about the effect of pollutants on a river, you might introduce the facts in the passive voice, because in terms of the effects, it doesn't MATTER who did the action:

"The pollutants were released into the lake in 1979. Significant amounts were detected in the last test of the area, in 2010."

If this was an expose on the SOURCE of the pollutants, maybe you would want to avoid the passive voice, and say:

"Company X, Company Z, and Farmer B released the pollutants into the lake in 1979. While the govnerment said that it was all cleaned up immediately, independent labs detected significant amounts in the area in 2010."

Or there's the old "John Smith found the body on the courthouse steps," vs. "The body was found on the courthouse steps." If John Smith is just a passerby, he's not really important to the story, and it's distracting to have him in there.

I think there's also a tradition of using passive voice in lab reports, to make things seem less personal. "I turned the burner on" vs "The burner was turned on." Again, I guess it's trying to de-emphasize the importance of the actor. It doesn't matter WHO turned the burner on; the important thing is the act.