The punctuation rule we’ll discuss in this post is the use of a comma after an introductory element in a sentence. This is the second of the 3 Fundamental Comma Rules in my free guide. (It is also the second most common error in a list of Top Twenty mistakes in writing, which we’ll look at later in this post.)
An introductory element is something that appears at the beginning of a sentence and thus introduces it.
All sorts of words or word groups can introduce or begin a sentence, from a single word or short phrase to a clause:
short phrase: In 1865, the Civil War ended.
clause: When the Civil War ended in 1865, northern photographers extensively documented the fallen Confederate strongholds.
The traditional rule is to use commas to separate introductory elements from the main sentence. For example, writing guides usually say to use a comma after every introductory element—whether word, phrase or clause—to clarify where it ends and the rest of the sentence begins.
Traditional rules tend to be prescriptive—telling you what you should do—rather than descriptive –telling what you already do in practice. These conventions or rules are seen as providing a standard of communication and as helping to prevent errors and misunderstandings.
Missing a comma after an introductory element is the second most common error as identified in a large-scale study by Andrea Lunsford and Karen Lunsford published in 2008. (This study built on earlier 1986 research, “The Twenty Most Common Errors,” by Andrea Lunsford and Robert Connors, authors of one of my favorite handbooks, The Everyday Writer.)
The studies focused on college writing patterns, but in my teaching, I have found similar errors in adult writers. (The 2008 research presented in Top Twenty and we’ll be looking at other top twenty errors in future blog posts.)
Though the items, or errors, on the lists have changed somewhat over time, both studies identified errors that are the most likely to attract readers’ negative attention. The error or missing a comma after an introductory element appears at the top of both lists. That’s why it’s important to understand the rule.
We saw in my previous blog post and in my free comma guide that the serial comma can be a source of controversy. But it is also a matter of choice-whether you use it depends on your own writing style or the in-house style of your company or organization, such as a workplace or the AP style guide.
While the use or omission of a comma after an introductory element may not be as controversial as the serial comma, its use can also be a matter of style: many people elect not to use it.
However, it is generally agreed that
A comma is optional with small elements.
But a comma is required with adverb clauses.
And a comma is always required to prevent misreading.
As Lunsford and Connors write, “you’re never wrong if you do use a comma after an introductory element” (11).