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Editing Tip: Comma Splices

More ways to make your manuscript more readable by using best practices for commas.

Another article on AJE Scholar describes ways to take longer sentences and split them into smaller pieces. In it, we focused on sentences that contained too much information to easily convey to a reader at once. Here, we'll focus on a different type of sentence that should be split or changed: one with a grammatical error called the comma splice.

Simple and compound sentences

As you are no doubt aware, sentences are identified by the capital letter at the start (in almost all cases) and the period at the end. However, it is easy to construct a sentence that appears correct while containing a grammatical error.

Many sentences (like this one) include only one independent clause. Such sentences are called simple sentences. In other cases, the sentence contains additional information expressed using a separate independent clause. These sentences, called compound sentences, require special linkages that connect the two ideas they contain. Here are some examples of compound sentences:

  • The two organisms contain several syntenic genes, but the majority of their genomes are highly divergent.
  • Ten patients were admitted with disease symptoms, and two patients died within 48 hours.
  • Over a million people contract this disease annually, yet very little is known about its etiology.

These examples use the most common method of creating a compound sentence, namely linking the two clauses with a comma and a coordinating conjunction. Another option for linking two independent clauses is the semicolon, which requires no conjunction:

  • Ten patients were admitted with disease symptoms; two patients died within 48 hours.
  • Trial results were entered into the database; all records were coded to preserve anonymity.

Comma splice errors

But what of the common error mentioned above? The comma serves many functions in English, including separating items in a list, delineating nonrestrictive elements, and ending a dependent clause at the start of a sentence. Despite its adaptability, however, the comma does not separate two independent clauses by itself. Consider the following examples:

  • Ten patients were admitted with disease symptoms, two patients died within 48 hours.
  • Many companies give back to the community, we do too.
  • It is nearly 5:30, we cannot reach the town before dark.

What should you do with a comma splice? Generally, just change it to follow the examples above using a semicolon or comma and conjunction (as in It is nearly 5:30; we cannot reach the town before dark OR It is nearly 5:30, so we cannot reach the town before dark). Alternatively, you can separate the splice into two sentences (It is nearly 5:30. We cannot reach the town before dark.).

We hope that today's post has given you some tools for editing your writing. As always, if you have questions about a particular sentence, let us know at [email protected]. Thanks!

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