Features May/June 2024

An Exploration of the Oxford Comma

By Rachel Holmes, Student Member

Although no universal rule exists, the Oxford comma has developed a strong reputation for controversy, among editorial experts and novices alike.

The Oxford comma, also known as the serial comma, serves as the last comma in a series. It typically appears after the word and or or prior to the last item in a list. A series can be either (1) simple—meaning it is short and easy to understand—or (2) complex—meaning it may contain multiple conjunctions or clauses:

  1. The American flag uses the colors red, white, and blue (with the Oxford comma appearing after white).
  2. Every morning, I wash my hair, brush my teeth, and cook and eat breakfast (with the Oxford comma appearing after teeth).

Because no universal rule exists whether to use the Oxford comma, it has developed a strong reputation for controversy, even among those who are unfamiliar with editorial nuances. From meme culture to TED Talks, from dating profiles to song lyrics—even being the center of a $5-million labor lawsuit settlement in 2017—the debate over whether to use the Oxford comma has permeated every corner of American culture. Despite the heated arguments between laypeople and experts alike, a technical communicator must take a clinical approach to Oxford comma usage.

In fact, the reader of this article will notice the author’s own preference toward using the Oxford comma. This article explores key differences between style guides throughout specialties and geographical regions, as well as the potential impacts of cultural and technological influences on the comma’s usage. The exploration offers editors, writers, and technical communicators insights into how they should think about their writing and editorial decisions.

Style and House Guide Recommendations

Many attribute the Oxford comma’s first appearance in style guides to the English printer Horace Hart. In 1905, Hart updated his style guide for the Oxford University Press stating, “Commas should, as a rule, be inserted between adjectives preceding and qualifying substantives” (37). This change seemed to trigger a similar style in the U.S. The Chicago Manual of Style (CMoS) released their first edition in 1906, stating, “Put a comma before and, or, and nor connecting the last two links in a sequence of three or more” (46). It wasn’t until 1978 that Peter Sutcliff gave the comma the name “Oxford Comma” (5), though he credited editor F. Howard Collins who wrote in Authors’ and Printers’ Dictionary, “Insert after each adjective (except the last) preceding and qualifying a substantive, as ‘he was a cautious, eloquent, intrepid, and wise man’” (307).

Today, most American English style guides recommend that writers always use the Oxford comma, including CMoS, American Medical Association Manual of Style (AMA), U.S. Government Publishing Office Style Manual (GPO), and Modern Language Association Handbook (MLA). Beyond these, many global corporations headquartered in the U.S., including Microsoft and Apple, indicate in their house styles that writers must use the Oxford comma. The Associated Press Stylebook (AP) (2019) is perhaps one of the only American style guides that states the writer or editor should decide when to use the Oxford comma: “Use commas to separate elements in a series, but do not put a comma before the conjunction in most simple series” (323). Primarily, journalists or public relations writers tend to reference the AP Stylebook, while technical communicators and business writers typically use a variety of style guides such as CMoS and MLA.

Despite the Oxford comma’s first attribution in the UK, many British English—as well as Australian and Canadian—style guides and house styles indicate that writers and editors should omit the Oxford comma in most situations. The Australian government says, “Restrict the use of the Oxford comma” (2023). The Canadian government concurs, stating, “Place a comma before ‘and’ and ‘or’ only if it will help people understand a list of items in a sentence” (2020). Oxford University’s style guide, New Hart’s Rules, recognizes its history with the Oxford comma, saying, “For a century, it has been part of Oxford University Press style to retain or impose this last comma consistently, to the extent that the convention has also come to be called the Oxford comma” (Waddingham 2014). However, New Hart’s Rules doesn’t clearly indicate to use or avoid the Oxford comma, saying simply, “The general rule is that one style or the other should be used consistently,” before it provides multiple examples of when to use the comma—yet provides no examples when to omit.

In general, style guides and house styles that support the Oxford comma say it prevents ambiguity. Those that omit the Oxford comma in certain cases agree with this logic, suggesting that writers should only include it when a sentence risks clarity. Yet, when a style guide states that a writer may choose to use the Oxford comma, it doesn’t indicate why writers shouldn’t use it, only when they should. See Table 1 for details from each of the aforementioned style guides regarding usage of the Oxford comma.

Table 1: Style Guide Requirements for the Oxford Comma

Arguments Supporting and Opposing the Oxford Comma

Style guides are not the only authoritative sources calling the Oxford comma necessary for clarity. Lasch calls it “almost universally preferred, at least in the United States” (Lasch 2002). Marcello says that leaving out a serial comma “invites misunderstanding” (Marcello 2020). Follett synthesizes these ideas: “One must question whether the advantage [of saving space] outweighs the confusion the omission causes… Inclusion can never confuse” (Follett 1966). Countless other American modern English usage books all come to the same conclusion: the best way to guarantee a lack of confusion in a series is to include the Oxford comma.

Despite the arguments in the U.S. for using the Oxford comma in most prose, newspaper house styles around the world omit it. The New York Times says eliminating the comma has a “more rapid feeling in the prose” (Corbett 2015). The BBC concurs: “[Commas] can also create unnecessary clutter and may often be avoided.” While not a direct source, the McMaster University Editorial Style Guide (2019) follows the Canadian Press Stylebook and bluntly says, “We don’t use the serial comma” and concludes the discussion on commas with the advice, “When in doubt, err on the side of too few commas” (2016, 27). These recommendations starkly contrast the advice seen in most American style guides.

Likely, the practice of eliminating the Oxford comma dates back to the days of typesetting and ink costs. According to The New York Times: “News writing has traditionally omitted the serial comma… perhaps to save time and effort in the old days of manual typesetting” (Corbett 2015). Indeed, journalists working with strict character counts and space limitations may look for every advantage to save space, seeing a simple series as an easy place to start. Follett calls this reasoning the only logical argument to omit the Oxford comma (Follett 1966). Yet, modern newspaper editors and journalists don’t mention such reasons in today’s discourse. Instead, their argument has shifted toward clarity and the true meaning of an article. Carballo et al. say, “Brevity rules over clarity in journalism,” suggesting that writers should sacrifice some details in favor of getting to the point (Carballo 2022). And Perlman believes, “We’ve become less passionate in the fight over the Oxford comma, because it’s usually not about the comma at all. It’s about intent and clarity” (Perlman 2017). Certainly, some journalists more directly oppose the Oxford comma. Sommer calls it, “Clunky, choppy and unnecessary” (2022). Blake equates mandatory usage to mindless cluttering (Blake 2019).

In summary, advocates of the Oxford comma claim that it maintains clarity and consistency. Opponents say it clutters a simple series. Despite the passionate statements on both sides of the argument, it appears few to no true studies have been conducted to understand how the Oxford comma impacts clarity or ambiguity. Therefore, technical communicators and editors must decide for themselves whether the Oxford comma makes a statement clearer. This challenge raises an interesting dilemma: editorial nuances aside, who decides whether a series is clear and simple or complex and ambiguous? An author may write something and consider it straightforward, yet an editor may inquire for details to clarify the copy. Similarly, an editor must consider how an audience will interpret the content before making editorial changes. Decisions regarding the Oxford comma are no exception; in situations where it may be considered optional, editors must diligently investigate the purpose and intent surrounding a sentence before deciding whether to add or delete.

Clarity for the Known and Unknown Audience

All technical communicators should agree that any written or editorial decision must start with the audience of the content. As Hamlin et al. point out, “For most technical communicators, audience is the most important consideration in planning, writing, and reviewing a document” (Hamlin et al. 2022). By deeply understanding the audience, communicators can carefully craft and present their message clearly and succinctly. But researchers such as Mathes and Stevenson believe “unknown or unanticipated audiences” impact how writers identify their audience, and there may be audiences in addition to the ones that a writer initially plans for (Mathes and Stevenson 1976).

Nearly 50 years after Mathes and Stevenson’s claim, the “unknown audience” has exponentially expanded. The nature of our interconnected, digital world means that a real audience is most likely an interspersed, global community. This global community can read or access content anywhere in the world. They may rely on audio readers, AI, and automatic translations into a native language to consume information. Consumers may read summarized takeaways, shared screenshots, and out-of-context quotes. With this global and technological viewpoint, determining whether the audience will find the content clear—and therefore, whether to implement or omit the Oxford comma in a series—becomes a much harder question to answer. Because large language modeling and translation AI is still in its infancy, it may be many years before researchers understand the impact of punctuation on the accuracy of natural language processing models for automatic language detection and translation.

Furthermore, editors and authors alike agree on the importance of consistency in writing. Consistency—one of the commonly prescribed “Cs” in technical and business writing—helps an audience more clearly understand content while making it appear polished and professional. Consistency ties in very closely with the idea of credibility. The more errors or editorial inconsistencies, the more likely it erodes trust and understanding for the reader. A style guide or house style helps to solve these problems, giving editors and authors clear and consistent grammar rules that create a better experience for readers and build credibility for the author. Thus, an ambiguous rule surrounding a grammar decision—such as only including the Oxford comma when it improves clarity—embeds subjectivity into the grammatical decision. Even though these decisions may seem small, they impact consistency throughout the piece. For every decision whether to include or omit an Oxford comma, the editor must weigh two variables: whether the sentence is simple or complex, and whether the decision will appear consistent to the audience. Despite an editor’s best intentions, the audience will interpret editorial decisions based on their own understanding of a sentence’s purpose and the piece’s consistency.


Editors, authors, and technical communicators can leverage this commentary to understand that choosing when to use the Oxford comma isn’t as simple as a stylistic preference. Additional studies that focus on the Oxford comma and its usage may prove valuable for communicators and style guides alike about whether to keep the Oxford comma optional in simple series or require it in all cases. Studies could include: how much space a writer actually saves when omitting the Oxford comma in an article or newspaper; the impact of readability and flow on a diverse set of participants when using the Oxford comma; the differences in attempting to eliminate lists versus keeping a long series; and how punctuation impacts language translation, especially with the rise of automatic translators such as Google Translate or generative AI services such as ChatGPT.

Grammar rules—spoken and written—constantly change. Not too long ago, typographers used double spacing after each sentence. Yet CMoS began recommending single-space formatting in 2003: “A single character space, not two spaces, should be left after periods at the end of sentences” (61). Similarly, the UK avoids using the Oxford comma today even though it originated the rule over a century ago. Until various style guides agree upon a globally accepted standard, the discrepancies and arguments regarding the Oxford comma will continue among technical communicators, editors, and writers. If an editor follows a style guide that calls to omit the Oxford comma, they may need to come up with strict guidelines to qualify a list as complex or simple. Others may find ways to limit the use of complex series altogether. While clarity and consistency will remain at the center of these conversations, communicators must also consider the global environment, emerging technologies, and how a true audience will interpret their work.


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Rachel Holmes is a Master’s student in Rhetoric, Composition, and Professional Communication and a graduate research assistant at Iowa State University. She holds a Bachelor of Arts degree in English with an emphasis in Rhetoric and a minor in Technical Communications from Iowa State University. Her interests include technical communication, technical editing, visual communication, and generative AI, specifically AI applications within business communications and workflows. Prior to her graduate studies, she served as an accomplished content professional in the technology space at start-ups and global organizations.