It’s a well-established fact that proofreading your writing can be a very painful task. Yes, some writers smirk at the very mention of proofreading—they never proofread their work because their work is the product of the moment. But people who write for a living—as well as anyone who has to write important emails or assignments—can tell you that proofreading your work before you turn it in or press send is essential.
With proofreading, every little bit of help is welcome. The autocorrect and spell-check tools most word processors have are great, but they only amount to a single line of defense. Specialized proofreading software can sometimes be helpful, but there are many products out there that claim one thing and deliver another. You also have to pay for most of them, even though they won’t remove the need for you to check your writing. But that could be OK if they provide substantial help. And that leads us to Grammarly.
On paper, it sounds great. Grammarly is advertised as the world’s most accurate grammar checker. It can fix 250 types of errors, and it provides plenty of other features that will help users improve their grammar and vocabulary. A lot of its features are free. It’s available as a browser extension, a Microsoft Office add-in, a desktop app you can install on your computer, or a web page you can visit. But all of that means nothing unless the product works well in practice, and we want to see just how well Grammarly performs. So we’ll take it for a spin and see what we can find out.
How We’ll Test It
The full set of features offered by Grammarly includes a contextual spelling checker, a grammar checker, a punctuation checker, a sentence structure checker, an option to adjust the checks for genre-specific writing styles, a plagiarism checker, and a vocabulary enhancement tool. Grammarly also allows users to choose whether they’ll be using British English or American English, and it has an integrated dictionary and thesaurus.
For this test, we’ll be using a Grammarly Premium account, set to American English. We’ll devise a series of sentences that will test each of Grammarly’s features for some common (and a couple of less common) mistakes. The idea of the test is not to discover the limits of Grammarly and which types of errors are not included in the 250 Grammarly supposedly checks for. The idea is to determine the app’s value by testing it on sentences containing realistic mistakes that people often make.
To determine how well the plagiarism checker performs, we’ll take a couple of sentences from an article published on a lesser-known website and run them through the checker. We’ll then gradually change the sentences to see how well the plagiarism checker deals with rewording.
To test Grammarly’s effectiveness on different styles of writing, we’ll find an example from one of the seven major writing genres Grammarly recognizes. We’ll see how Grammarly does with the checks adjusted for that genre, and then we’ll try it with the checks adjusted for a couple of other genres to determine what the differences are.
We’ll end with an examination of how well the British English vs. American English setting works.
Contextual Spelling Test
The contextual spelling tool checks for misspelled words and correctly spelled words used in the wrong context. We’ll start with a sentence containing a few spelling mistakes that should be relatively easy to catch:
- Our grand-mother was the definative sourse on there family’s historie.
This sentence contains five spelling errors—an unnecessary hyphenation of the word “grandmother,” misspellings of “definitive,” “source,” and “history,” and the word “there” instead of “their.”
Grammarly flagged “grand-mother” as a possibly confused word and suggested “grandmother”; it suggested the correct spellings of “definative” and “sourse,” and it suggested changing “there” to “their.” As for “historie,” Grammarly flagged it as a possibly confused word and suggested we use “historic” instead. When we changed the word to “historic,” Grammarly didn’t flag it, which is why, in this part of the test, it got four out of five correct.
Let’s give it another go:
- She told tale’s about her Uncle Jim, with many colourful details—she remembered witch hankerchief he had on him when he met the famous playwrite.
In this sentence, there are five mistakes—“tales” has an extraneous apostrophe, “colorful” is spelled the British way, “witch” should be “which,” and “handkerchief” and “playwright” are both misspelled.
Grammarly didn’t flag “tale’s.” It did flag “colourful” as a British English spelling and suggested the American spelling. It caught “witch” as a possibly confused word and suggested we use “which” instead, and it flagged both “hankerchief” and “playwrite” and suggested the correct spellings. In this part of the test, Grammarly got four out of five correct.
At the end of the contextual spelling test, Grammarly caught eight out of ten mistakes.
Grammar and Punctuation
Grammarly’s grammar and punctuation checkers catch common grammatical errors and redundant, missing, and misused punctuation. We’ll test them simultaneously.
- Grandma remembered her teachers, Paula and Trevor, she could told you how their voices sounded when they was happy?
This sentence contains a comma splice (. . . Trevor, she . . .), uses the wrong tense of the verb “tell,” and contains an instance of subject-verb disagreement with (they was). The question mark at the end of the sentence is wrong, too.
Grammarly flagged the comma splice and offered a list of possible solutions: replacing the comma with a semicolon, adding “and” after the comma, or replacing it with a period and capitalizing the “s” in “she.” Grammarly also caught the mistake with “told,” and suggested changing it to “tell” or “be told.” The app also flagged the subject-verb disagreement, and it suggested the proper correction. As for the misused question mark at the end of the sentence, Grammarly didn’t flag it.
But it did flag the word “Paula” and suggest a comma after it because it’s a part of a series of three or more words. This suggestion would have been correct if we were indeed dealing with a list. However, grandma remembers Paula and Trevor, who were her teachers. She’s not remembering her teachers plus Paula and Trevor. All in all, Grammarly caught three out of four. As for the serial comma issue, it was a false positive, but it erred on the side of caution. We checked whether it would flag a real serial comma issue:
- Trevor never showed up to class without his bowtie, his hat and his umbrella.
And it did. One out of one.
- My brother, and me would of listened for hours at time.
In this sentence, there’s an unnecessary comma, “me” was used instead of “I,” “would of” was used instead of “would’ve,” and there’s an article missing before “time.”
Grammarly flagged the unnecessary comma after “brother.” It suggested “I” instead of “me,” and flagged “would of” with a comment that this phrase, as well as similar phrases like “could of,” are never correct. It also flagged the missing article before time, suggesting that we add “a” or “the.” In this case, Grammarly caught four out of four. In total, Grammarly flagged eight out of nine errors and gave one false positive.
Sentence Structure, Style, Vocabulary Enhancement
The sentence structure checker finds misplaced words, incorrect sentence structure, and incorrect word order. The style checker is a bit more subjective—it flags wordiness and redundancies, but it’s also supposed to enhance your writing style, without stating exactly how. The vocabulary enhancement tool offers synonyms and suggestions about word use.
- Having sat in the chair, the storytelling would begin.
This sentence contains a dangling modifier—“having sat in the chair” doesn’t refer to “the storytelling.” Grammarly caught the mistake and urged us to rewrite the sentence to avoid it. One out of one.
- My brother and I inherited her own talent for telling stories, but we display it in various different ways: I became a fiction writer because I wanted to create my stories, and my brother became a decent documentary filmmaker because he was interested in other people’s stories; stories were the greatest gift we got from our grandma, and we will always remember where we got it from.
Four things are wrong with this sentence. It was written to be very long, there’s an unnecessary “own” near the beginning, “various different” is a redundancy, and the sentence ends with a preposition. While the unnecessary word and the redundancy are clearly mistakes, it’s not necessarily a problem for sentences to be very long, and they can end with prepositions.
Grammarly flagged the whole sentence for wordiness and suggested we break it into smaller ones. It caught the two obvious mistakes, suggesting we delete “own” and “different.” It didn’t find the preposition at the end of the sentence. Because the 68-word sentence might need some chopping, and because sentences can sometimes end with prepositions, this is four out of four.
- Paul’s grades were better.
Grammarly flagged the incomplete comparison in this sentence. One out of one.
- Was a long summer.
This sentence is missing a subject, and Grammarly flagged it correctly. One out of one. So far, we haven’t seen any vocabulary enhancement suggestions, but for sentence structure and style, Grammarly got seven out of seven.
We used this paragraph to test Grammarly’s plagiarism checker:
- Offering someone a drink is a sign of trust and friendship and it is a faux pas to turn down the proposal. You’d not want to offend a local by declining their offer of a drink and have to deal with a confrontation as your glass is hurled at the glass splashbacks of a bar! Vodka is always drunk neat and without ice, as adding anything is seen as compromising the purity of the drink. Unless of course the vodka is mixed with beer, which creates a hefty blend that Russians call ‘yorsh’.
The paragraph was taken from the website blog.joytours.com, and Grammarly correctly identified the source and flagged it as 100 percent unoriginal. It also offered a suggestion for a vocabulary enhancement, saying that “blend” might be pair better with “strong” instead of “hefty.”
By changing only a couple of words in the original material, we managed to get a 100 percent original rating:
- Offering someone a drink is a good sign of trust and friendship and it is a faux pas to turn down the proposal. You’d not want to offend a native by declining their offer of a drink and have to deal with an argument as your glass is hurled at the glass splashbacks of a bar! The national drink is always drunk neat and with no ice, as adding anything is seen as compromising the integrity of the drink. Unless of course the drink is mixed with lager, which creates a strong blend that Russians call ‘yorsh’.
We also got two more vocabulary enhancement warnings—Grammarly told us that we repeated the word “drink” too many times, and that “strong” is an overused term we might want to replace. Both times, Grammarly gave suggestions for substitutes.
Genre-Specific Writing Checker
So far, we’ve checked everything using the default “general” setting Grammarly offers. To see if changing this setting makes any difference, we’ll use part of a research proposal, run it through a couple of genre-specific checks, and see what we get.
- Limitations of the current research will be identified, along with suggestions for how future research can build upon the findings of the current study. One limitation to the generalizability of the findings is the use of only one photograph of one infant of a particular age. Future research could utilize photographs of infants of a variety of ages to establish the robustness of the results of the present study. Finally, the results and importance of this study will be summarized.
Grammarly instantly flagged the paragraph as plagiarism (it came from a PDF file downloaded from a source on the web). Under the “general” setting, Grammarly identified the words “current,” “photographs,” and “infants” as overused terms and offered synonyms to replace them. When we set the writing style as “research proposal,” “infants” disappeared from the flagged list. Selecting “business letter” brought “infants” back. Changing the style to “end-user assistance” removed “infants” again but also brought a style tip—technical writing is almost exclusively written in the present tense, and the paragraph contains two uses of the future tense. Other document types we tried produced similar results.
British English vs. American English Test
For this test, we’ll create a series of sentences that contain distinctly British spelling and grammatical structures.
- The flock were flying. John had a nap. I will go there at the weekend. This sentence is different to the last one. I liked the flavour and colour of it. Let’s see what we learnt yesterday. Mr Peters told me so.
In the first sentence, the verb “were” is used with the collective noun “flock,” as it is in British English. In the second sentence, we used “have” instead of the usual American “take.” In the third sentence, the preposition “at” was used instead of “on,” and in the fourth “to” was used instead of “from.” “Flavour” and “colour” are British spellings, and the past tense “learnt” was used instead of “learned.” In the last sentence, the title “Mr” was written without a period after it.
Out of the eight Briticisms present in these sentences, Grammarly flagged five—the plural verb with collective nouns, the “-our” spellings of “flavor” and “color,” “learnt” instead of “learned,” and the missing period after a title. That’s five out of eight.
Just for the fun of it, we ran the same text through a complete check but with Grammarly set to British English, and no flags were raised. Let’s see how Grammarly works the other way around.
- I have gotten in before. We learned advanced math in college. Do me a favor and take a bath. You broke your nose—does it hurt? We were well organized. He had a dialog.
In the first sentence, the past participle “gotten” was used instead of “got.” In the second, “math” was used instead of “maths”, the preposition “in” was used instead of “at,” and “college” was used instead of “university.” “Favor” was spelled the American way in the third, and “take” was used instead of “have.” The fourth sentence contains the simple past tense instead of the present perfect, which would be correct in British English. In the last two sentences, the words “organized” and “dialog” are spelled in the American English way.
Grammarly flagged only the American spellings of “favor,” “organized,” and “dialog” and failed to notice the rest of the issues. That’s three out of nine, and it brings us to a total of eight out of seventeen.
In the tests that were quantifiable, Grammarly was asked to check for forty-three mistakes, and it managed to find thirty-one of them. That’s 72 percent. But the numbers only tell part of the story.