When you get your draft back from your committee, it may be covered in comments—hopefully not, but it happens! Some comments may be straightforward and simple to address. Others may require major changes to your thought process or explanations. You may also get a comment about your grammar that leaves you completely confused.
One comment that I’ve seen on several different papers has said, “Use less passive voice.” The commenter didn’t mark every instance, and they didn’t explain what they meant. The writer didn’t know how to start addressing their comments. I’ve noticed two different reasons for this: sometimes, passive voice is difficult to identify; in some other instances, the professor didn’t really mean passive voice. I’ll give you a few tips to help you identify passive voice in your writing and provide a few pointers in case your professor wasn’t actually referring to passive voice.
What is passive voice?
Passive voice is a grammar term that’s used to describe a sentence in which the subject isn’t performing the action in the sentence. For example, in the sentence The researchers used interviews to obtain rich data, “researchers” is the subject, and they’re the ones “using interviews.” The passive form of that sentence would read, Interviews were used to obtain rich data. In this sentence, the action is still “used,” but it’s not clear who is “using.”

If you’re concerned about passive voice in your document, search your document for “to be” verbs. Every passive voice sentence includes a “to be” verb. Then, check whether that “to be” verb is followed by a verb that ends in “-ed” (or an irregular form of the same kind of verb). If it is, there’s a good chance the sentence is written in passive voice.
Check the sentence by asking one more question. Is the subject noun performing the action in the sentence? If not, it’s a passive voice sentence.
The next step is to decide whether to fix the sentence. Note that not every passive voice sentence needs fixing, especially not in academic writing.
Is Passive Voice Always Bad?
If using passive voice makes your sentence less clear, it needs to be changed. In many cases, especially in qualitative writing, it’s important to recognize that you, the writer, performed the research and did the work behind the dissertation.
In other instances, it may be advantageous to hide who did the work. Maybe you worked with a team, and there’s no reason to mention exactly who performed each step. Or, it may make sense to use passive voice in order to help the reader focus on the action itself, not on the doer.
But I didn’t use much passive voice! What else could the comment mean?
You’ve checked your paper for “to be” verbs combined with “-ed” verbs and checked the subject versus the action. What if you don’t find much passive voice?
It’s possible that your professor didn’t really mean passive voice. After all, they’ve specialized in their field, which is likely not grammar. (That’s why even professors hire editors.) They may also mean that you’re using vague language. Most commonly, I’ve seen professors refer to sentences that start with “there” and “it” as examples of passive voice. If you’re unsure about what they meant and suspect they didn’t really mean passive voice, I’d recommend searching your document for sentences that start with the frequently vague words “there” and “it.”