most common errors: commas

Haley Clapp July 20, 2025

Tags: #resources

Hello! This is Haley C., and welcome to my first post in my new blog series, Common Errors in All Writing. In this series, I will be breaking down the most common errors I see in writing from writers of all proficiency levels (yes, even the experts!).

I’m calling this series Common Errors in All Writing because I’m going to be making a sister series after this one called “Common Errors in ESL Writing,” where I will break down the most common errors I see specifically in writing by ESL (English as a Second Language) and international writers.

In this post, I start with the biggest bear: commas.

I know even bringing up the matter of correct comma use is going to trigger a headache for some of you—just take a deep breath, and we’ll get through this together.

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First, probably the most common error I see with commas is the overuse of commas when they are not needed.

This often happens because people add commas where they would naturally take a break when speaking the sentence out loud. While doing this might feel correct, I’m sorry to say that it often is not.

If the words that come after a conjunction (e.g., “and,” “but,” “or”) do not make a full sentence, there should generally not be a comma before the conjunction.

Ex: Smith and Roberts (2023) reported that the acceptance of technology was high among their respondents, and that this was correlated with less technology anxiety.

Because the latter phrase “that this was correlated with less technology anxiety” does not comprise a full sentence (an “independent clause”), the comma should be removed from this example.

Quick Definition:

Independent Clause: An independent clause contains a subject and a predicate (verb phrase) and can stand by itself as a simple sentence.

Ex: They are considered major contributors to the global decline of insect populations and can be found in nearly every country.

For synonyms specifically, it provides lists of similar words, phrases, and idioms, and it even creates lists of similar words in different parts of speech, e.g., nouns, adjectives, and verbs (a function a dictionary could only dream of).

Also, when you click on any synonym populated by your search, Power Thesaurus shows you not only the definition of that word but also ‘mutual’ and ‘unique’ synonyms, as shown below.

And the cherry on top: Power Thesaurus is free, and its free version populates all top-rated search results (which is more than enough to get you started).

It also offers a PRO version, which I use and love, which provides even more search results and other customization perks.

If your head is spinning with all this functionality, try it out yourself—you’ll wonder how you ever lived without it.

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Purdue OWL

I’m originally from Indiana, the home of Purdue University, which operates the Purdue OWL (Online Writing Lab). Growing up, the pride we Hoosiers have for this world-renowned resource was evident—because it was mentioned in every English-related class I took through the end of high school.  

And truly, the Purdue OWL deserves the praise and attention it gets. It contains a stunning amount of information on any and every topic in English grammar, writing, citation, and beyond. It also has specific resources for areas such as subject-specific writing, job search writing, and even multilingual/ESL English resources.

I could try to list all the resources and topics covered on the Purdue OWL website, but it would eat the rest of this blog post.

Some lesser-known highlights among the Purdue OWL resources are as follows:

Personally, I use the Purdue OWL primarily as a quick reference to double-check that I am accurately applying style guides, as it offers resources and concise summaries of central points of major style guides, including APA (6th and 7th eds.), MLA, Chicago, and AMA.

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Google NGram

You can’t imagine how many hours I’ve spent sitting in front of a single phrase, wondering, “What is the best way to write this out of Options A, B, and C?” (This often comes down to prepositions—a common nemesis of writers and editors everywhere.)

Here is where NGram is a lifesaver: When you enter words or phrases into its search function, NGram displays a graph showing how those phrases have occurred in a corpus of books over the selected years. This is super useful for seeing which phrases are more common or frequently used.

An example I came across the other day: a paper I was editing interchangeably used the words “purchase intention” and “purchase intentions” to describe the same concept. As I wasn’t sure which was more correct/common to use, I ran a quick NGram search, which showed me the following:

Easy! So I chose “purchase intention” and used it throughout the paper.

NGram also has about 100 other super useful functionalities. I won’t list them here, but for a comprehensive guide, see Google’s About NGram Viewer page and be astounded.

However, there is perhaps an obvious disclaimer: NGram only shows you which words/phrases are more commonly used, not necessarily which iteration is grammatically correct. To check grammatical correctness, it is probably better to run a separate search. Or hire an editor ;)

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So there you have it! These resources are unimaginably helpful to me on an everyday basis, and I hope that my humble summaries make you feel comfortable enough to give them a try for your next writing or editing project.

But these are not the only resources I use! I’ve got an arsenal that I’ll continue to reveal to you in further blog posts. Keep an eye on my blog for future posts on other helpful resources I’ve found in my years editing. Thanks for reading!

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