What is a Comma Splice?
A comma splice joins two independent clauses, each of which could stand alone as a sentence, with only a comma: "The data were incomplete, the analysis was delayed." It is one kind of run-on sentence.
How to Tell if It's a Comma Splice
Cover the comma and read each side on its own. If both halves are complete sentences, with their own subject and verb, and nothing but a comma joins them, it is a comma splice. Words such as "however", "therefore" and "moreover" do not fix it: "The sample was small, however, the effect was strong" is still a splice.
Comma Splice Examples and Corrections
Comma splice: "The data were analysed, the results were significant."
- Full stop: "The data were analysed. The results were significant."
- Semicolon: "The data were analysed; the results were significant."
- Comma and coordinating conjunction: "The data were analysed, and the results were significant."
- Subordinate clause: "When the data were analysed, the results were significant."
- Semicolon with a conjunctive adverb: "The sample was small; however, the effect was strong."
Which Fix to Choose
Use a full stop when the ideas are separate, a semicolon when they are closely linked, a conjunction when you want to name the link (and, but, so), and a subordinate clause when one idea depends on the other. Varying the fixes keeps your sentence structure interesting.
Is a Comma Splice Ever OK?
In fiction and informal writing, short parallel clauses are sometimes spliced for rhythm ("I came, I saw, I conquered"). In academic writing, treat a comma splice as an error.
Final Tips
When proofreading, stop at every comma followed by a new subject ("it", "this", "the results", "we"). Choosing the right transition word and punctuation together fixes most splices.