A comma splice is a common writing error that occurs when two or more independent clauses in a sentence are incorrectly connected by a comma (where the comma neither demonstrates a relationship nor provides a strong separation).

Identifying a comma splice

Locate all of the independent clauses in a sentence. An independent clause can be located by identifying subject-predicate pairs. Once the subjects (bold) and predicates (italicized) in the following example are located the clauses are easier to identify:

The character becomes anxious, * he paces back and forth.

Each subject-predicate pair above stands alone as a complete thought. Thus, the sentence contains two independent clauses. Because the clauses are connected by a comma that is not followed by a coordinating conjunction, the result is a comma splice (indicated above with the symbol *).

Correcting a comma splice

Change the comma into a period

Although this method is grammatically correct, its overuse can lead to short, choppy sentences.

Enteric diseases are usually caused by infrequent hand washing, * students can avoid getting sick by frequent hand washing.
Enteric diseases are usually caused by infrequent hand washing. Students can avoid getting sick by frequent hand washing.

Change the comma into a semicolon

When using a semicolon, a transitional word, such as however or therefore (a conjunctive adverb), may be added to indicate the nature of the relationship.

History often repeats itself, * it is an important subject to study.
History often repeats itself; therefore, it is an important subject to study.

Add a coordinating conjunction

When included after the comma, a coordinating conjunction corrects a comma splice by indicating a relationship between the two independent clauses. The seven coordinating conjunctions are: and, but, for, or, nor, so, yet.

The thickness, the distribution, and the geometry are shown in the diagram, * the tectonic structure of the sediments and possible unconformities can also be seen.
The thickness, the distribution, and the geometry are shown in the diagram, and the tectonic structure of the sediments and possible unconformities can also be seen.

Change one independent clauses into a dependent clause

If an independent clause can be made dependent on the other for its meaning, it can be rewritten using a subordinating conjunction, such as: after, although, as, because, before, if, since, that, unless, until, when, where, or while.

Computers are used from an early age, * the art of penmanship is being lost.
Since computers are used from an early age, the art of penmanship is being lost.

Change an independent clause into additional information (a phrase or appositive)

Often, it is possible to use the information presented in one of the independent clauses as an appositive. This simplifies the comma splice into one clear idea that includes additional information.

Television is often criticized as low culture, * it is an important part of the study of popular culture.
Television, often criticized as low culture, is an important part of the study of popular culture.

Practice ↓

Identify and correct the comma splices within the sentences using one of the five methods above.

The Writing Centre offers help to students, the tutors can teach you how to construct a thesis statement.
Desktop computers are not as popular anymore, people are investing in laptops.
The Registrar’s office released the exam schedule, my first exam is on April 8th.
The painting is beautiful, it has an exquisite use of colour.
The library has books on reserve behind the circulation desk, many books on reserve have a time limit if they are borrowed.
A lot of people do enjoy tea, order both tea and coffee for the meeting.
The purpose of a conclusion is to wrap up your argument, there is no reason to introduce new information
I need some business clothes for this job interview, I am going to shop for some tonight.
New discoveries are constantly made in astrophysics, each new textbook you buy will become dated after a few months of purchase.
Lately I have been hard to reach, I have spent too long alone at the cottage.

Answers ↓

The Writing Centre offers help to students. The tutors can teach you how to construct a thesis statement.
Desktop computers are not as popular anymore because people are investing in laptops.
The Registrar’s office released the exam schedule; my first exam is on April 8th.
The painting, with an exquisite use of colour, is beautiful.
The library has books on reserve behind the circulation desk. Many books on reserve have a time limit if they are borrowed.
A lot of people do enjoy tea. Order both tea and coffee for the meeting.
The purpose of a conclusion is to wrap up your argument; there is no reason to introduce new information
I need some business clothes for this job interview so I am going to shop for some tonight.
As new discoveries are constantly made in astrophysics, each new textbook you buy will become dated after a few months of purchase.
Lately I have been hard to reach, since I have spent too long alone at the cottage.