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Passive voice

Passive voice is a sentence construction in which the thing being acted on becomes the grammatical subject, formed with a form of “to be” plus a past participle, and in which the actor can be left out entirely.

Last reviewed 15 August 2026 · The HumanFlow team

In plain English

Active: someone does something. Passive: something is done, and you may never learn by whom.

The reliable test is to add "by zombies" after the verb. If the sentence still works grammatically, it is passive.

A worked example

The same fact, three ways.

Active:            The registrar rejected the appeal.
Passive, agent:    The appeal was rejected by the registrar.
Passive, no agent: The appeal was rejected.

Zombie test:       "The appeal was rejected by zombies."  → grammatical → passive
                   "The registrar rejected by zombies."    → broken     → active

The third version is the one to notice. It is shorter than the second and complete as a sentence, and it has quietly removed the only party who could be asked to explain the decision.

That is not automatically evasive. If the registrar's identity is irrelevant, or already established, dropping it is simply tidy.

It becomes a problem when responsibility is the subject at hand and the construction is doing the omitting for you.

Why it matters for AI detection

Passive voice is heavily over-policed. Style checkers flag it on sight, which has produced a generation of writers who believe it is an error. It is not — it is the correct choice whenever the actor is unknown, unimportant, or genuinely not the point.

Scientific writing uses it deliberately and by convention: "the samples were incubated" keeps attention on the procedure rather than the technician, and many journals still prefer it in methods sections.

The version worth examining in your own draft is the agentless passive in a sentence about a decision, a finding or a failure — because that is where the missing actor changes what the sentence claims.

Commonly confused with

Nominalization
Passive voice reorders a sentence around the thing acted on. Nominalization turns the verb itself into a noun. They compound each other but are independently fixable.
Past tense
"The registrar rejected the appeal" is past tense and active. Tense is when it happened; voice is which participant the sentence is built around. Any tense can be either voice.

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Part of the AI detection glossary.