Active vs Passive Voice in Academic English

If a teacher or a grammar tool has ever told you to "avoid the passive voice," you have probably started treating it like a mistake — something to hunt down and delete from every sentence. For non-native English writers, this advice is confusing, because the same academic papers you are told to imitate are full of passive constructions. So which is it: is passive voice wrong, or is it how serious academic English actually sounds?

The honest answer is neither. Passive voice is a tool, not an error. Used in the right place, it is precise and professional. Used everywhere, it makes your writing heavy, vague, and hard to read. This guide explains what each voice is, how to spot the passive, and — the part most advice skips — exactly when each one is the stronger choice in academic writing.

What active and passive voice actually are

Voice is about the relationship between the subject of your sentence and the action. In the active voice, the subject does the action. In the passive voice, the subject receives the action, and the doer either moves to the end of the sentence or disappears entirely.

Active: The researchers measured the temperature.

Passive: The temperature was measured (by the researchers).

Notice what happened. In the active version, "the researchers" is the subject and they are doing the measuring. In the passive version, "the temperature" becomes the subject — it is being measured — and the researchers can be tucked into a "by" phrase or dropped completely. Both sentences are grammatically correct. They simply put the spotlight on different things.

How to spot the passive voice

You cannot decide when to use the passive until you can reliably see it. The formula is simple:

passive = a form of "to be" + a past participle

A form of "to be" is is, are, was, were, be, been, being, has been, have been, will be. A past participle is the third form of a verb — often ending in -ed (analyzed, reported, conducted) but sometimes irregular (written, taken, shown, given).

Passive: The survey was distributed to 200 students.

Passive: These findings have been confirmed by later studies.

Passive: The variable is defined in Section 3.

A fast trick if you are unsure: add the words "by zombies" after the verb. If the sentence still works grammatically, it is passive. "The survey was distributed by zombies" works — so it is passive. "The researchers distributed the survey by zombies" does not work the same way — so that one is active. It is silly, but it is reliable.

When passive voice is the right choice

Here is where most "avoid the passive" advice fails ESL writers. In academic writing, passive voice is often exactly what you want. There are three clear cases.

1. When the doer is unknown or irrelevant

If nobody cares who performed the action — or you genuinely do not know — the passive lets you skip naming them without an awkward "someone" or "they."

Active (worse): Someone calibrated the instrument before each trial.

Passive (better): The instrument was calibrated before each trial.

The reader does not need to know which lab technician turned the dial. The fact that calibration happened is the point.

2. When you want to foreground the result

Academic writing is often about findings, not about you. Passive voice moves the important noun — the result, the sample, the effect — to the front of the sentence, where the reader's attention naturally lands.

Active: We observed a 12% increase in yield.

Passive: A 12% increase in yield was observed.

If the increase is the star of the paragraph, the passive version keeps it in the spotlight. This is also why passive helps you maintain a consistent topic across several sentences — the thing you are discussing stays in the subject position.

3. When field convention expects it (methods sections)

Methods and procedure sections describe what was done, step by step, where the actor is always "the researchers" and saying so every time would be tedious. Passive voice is the traditional default here.

Passive: Samples were collected at three sites, frozen at -80 degrees C, and shipped overnight.

Writing this in the active voice — "We collected the samples, we froze them, we shipped them" — repeats "we" until it grates. The passive keeps the focus on the procedure, which is what a methods section is for.

When active voice is stronger

Outside those cases, active voice usually wins. It is clearer, shorter, and more honest about who did what.

Clarity and accountability

Passive voice can hide responsibility. Sometimes that is convenient — and that is exactly the problem.

Passive (vague): Errors were made in the initial data collection.

Active (clear): The first research team made errors in the initial data collection.

The passive version quietly avoids saying who made the errors. In an argument, a discussion, or anywhere you are making a claim, your reader wants to know who is acting. Active voice tells them.

Shorter, stronger sentences

Passive constructions almost always add words — an extra "to be" verb and often a "by" phrase. Over a whole paper, that weight adds up.

Passive (13 words): The hypothesis was tested by the team through a series of controlled experiments.

Active (10 words): The team tested the hypothesis through controlled experiments.

Same meaning, three words lighter, and the action verb does the work instead of hiding behind "was tested by."

The decision heuristic

You do not need to analyze every sentence. Use this quick rule when you are drafting or revising:

Default to active. Switch to passive only when you can name a specific reason — the doer is unknown or irrelevant, the result deserves the spotlight, or your field expects passive in this section. If you cannot name the reason, rewrite it in the active voice.

This flips the usual ESL habit. Instead of reaching for passive because it feels formal, you reach for active by default and justify each passive on purpose.

Use passive when / use active when

Sciences vs humanities: field conventions differ

There is no single rule across academia, and this is where many ESL writers get conflicting advice. The convention depends on your field.

Hard sciences and engineering have historically favored the passive, especially in methods, to sound objective and keep the researcher out of the frame. That is changing — many leading journals (and style guides like the APA's) now encourage active voice and first-person "we" for clarity. But passive is still common and accepted, particularly in procedures.

Humanities and social sciences generally prefer the active voice. Argument-driven writing — history, literature, philosophy — values a clear authorial position, so "I argue" and "Smith demonstrates" are normal and expected.

The practical move: read three or four recent papers in your exact target journal and notice what they do. Field convention beats any blanket rule, and matching your journal's house style signals that you belong in the conversation.

Why ESL writers over-use the passive

If you write in English as a second language, you have probably been told that academic prose should be impersonal — no "I," no "we," nothing that sounds like an opinion. The passive voice is the easiest way to achieve that, so it becomes a default. It feels formal. It feels safe. It lets you avoid deciding who the subject of the sentence is.

The cost is that your writing turns heavy and faceless. When every sentence follows the "X was done" pattern, the reader loses track of who is doing what, and the rhythm flattens into something monotonous. That same uniform, low-variation rhythm is part of what makes prose read as machine-generated — which is one more reason to mix active and passive deliberately. If your English already tends toward stiff, translated-sounding constructions, it is worth understanding why your English sounds translated and how to fix awkward English phrasing at the sentence level.

Before and after: putting it together

Here is a short paragraph drowning in passive voice, then a revision that keeps passive where it earns its place and switches the rest to active.

Before (all passive): "The data were collected and were analyzed using regression. It was found that a significant effect was produced by the treatment. These results are believed to be important and further research is recommended by the authors."

After (mixed, deliberate): "We collected the data and analyzed it using regression. The treatment produced a significant effect. We believe these results are important, and we recommend further research."

The revision keeps the writing clear about who acted, cuts the word count, and varies the sentence rhythm — while a methods-style passive ("the data were collected") would still be perfectly fine if the journal preferred it. That is the whole skill: not avoiding passive, but choosing.

Check your voice as you write

Spotting passive constructions across a long document by eye is tiring, and the "by zombies" test gets old after the tenth paragraph. A faster route is to run your draft through a free Passive Voice Detector, which highlights every passive sentence so you can decide — keep it or flip it — one at a time, with the reason in mind.

When you want that judgment built into your whole writing workflow, the Diglot grammar checker flags passive voice in context and shows the active rewrite alongside it, so you stay in control of the choice instead of blindly deleting every passive sentence. It is designed for bilingual writers who want their academic English to read clearly without losing the precision the passive voice sometimes provides. Write with intent, keep the passive where it belongs, and let the rest of your sentences say plainly who did what.