I recently read a tweet from a writer who was thrown into a state of self-doubt because she disagreed with something her grammar checker identified as wrong. As a language nerd (commonly known as a copy editor), I love it when proofreading software keeps me from making silly mistakes. But also, as a language nerd, I know when proofreading software is completely missing the mark. Which it does. Regularly.

Language is incredibly complicated. I am continually impressed with how much the software can keep up with that complexity, but trust me, it’s not perfect. Here, I’ll break down how modern grammar checkers still get things wrong. That way, when you disagree with your proofreading software (which will happen if you spend any significant amount of time writing on-screen), you can be confident and trust your gut.

The first thing you need to know is the difference between copy editing and stylistic editing. There are several different levels of editing, but for now proofreading software focuses on concerns from these two editing levels.

Copy Editing

Copy editing is what most people think of when they hear the word editing. It’s an edit for technical correctness in grammar, punctuation, usage, and spelling. Proofreading software focuses predominantly on grammar and spelling.

Grammar checkers have gotten fairly good at catching grammar and spelling errors. There are still several types of copy-editing concerns though that proofreading software completely overlooks. For instance, most grammar checkers won’t see anything wrong in this sentence: Too bee or, knot two beet, what is; the question.

While grammar checkers regularly overlook errors, they still for the most part follow the copy editor’s mandate to introduce no errors. Copy editors are a bit like doctors, in that our priority is to first, do no harm. While proofreading software doesn’t catch all grammar, spelling, and punctuation errors, it usually only highlights errors that are truly errors. For this reason, you can usually trust grammar checkers at this level to do nothing but improve your writing.

I point out this distinction because the situation is very different when modern software checks for stylistic errors.

Stylistic Editing

The recent trend in proofreading software has been to expand beyond checking for grammar and spelling. Now, a lot of software checks for some stylistic concerns as well.

Stylistic editing address clarity, coherence, and flow. The following sentence has nothing grammatically wrong with it: She was helped by her, the bleeding stopped, and then the ambulance was called. But stylistic editors immediately recognize that the sentence would be stronger without the passive voice and vague pronouns: Her mother helped Ann stop the bleeding and called the ambulance.

Stylistic issues are complex, more complex than grammar issues, because the same element that makes one sentence stylistically weak can make another sentence stylistically strong. Context is everything. There aren’t stylistic rules that are black and white “right” and “wrong.” There are only stylistic principles where “usually, it’s better if . . .” To see what I mean, let’s take a closer look at the passive voice.

Stylistic Principle: Avoid Passive Voice

Passive voice reverses typical sentence structures:

• Active voice: Tony walked the dog.
• Passive voice: The dog was walked [by Tony].

Passive voice makes the person doing the action (in this case, Tony) optional information – the sentence is still complete without naming who walked the dog. This function allows politicians and companies to apologize without taking the blame: “mistakes were made” rather than “I made a mistake.” When passive voice isn’t hiding information, it often sounds indirect and wordy. In most cases, passive voice makes for very weak writing and it needs to go.

But there are still cases where passive voice is the best choice! For example, when reporting violent crimes, news stations want to emphasize the victims rather than the perpetrator. They say, “seven students were killed in a mass shooting yesterday” rather than “John Doe killed seven students.” Passive voice is straight up necessary in this situation.

Back to Computers

It is so hard for software to be able to tell when the violation of a stylistic principle is truly hurting the quality of writing. It all depends on the meaning rather than the syntax. That’s why, whenever software points out stylistic issues, we need to treat them as potential weaknesses rather than objective errors.

If a computer points out a stylistic issue that you disagree with, trust your own ear! You’re probably right.

I know that a lot of writers find it difficult to distinguish between style and grammar, so my parting advice is simply to trust yourself. Proofreading software can be an incredibly useful tool, but it’s still fallible.

If you’re writing a casual piece, these technicalities honestly don’t matter too much. If your aim is to formally publish, you’ll probably end up hiring a human editor anyway. Leave the weird technicalities to your editor and focus on writing what sounds good to you.