A run-on sentence is “two or more independent clauses that are written as a single sentence but are not connected with appropriate punctuation or conjunctions” (Vosters, 2015). The most common form of run-on sentence is the comma splice. In a comma splice, a comma is used to join two or more independent clauses when actually a period, a semicolon, or a comma plus a coordinating conjunction (i.e., and, but, or, so, for, nor, yet) should be used.

Example:

Run-on sentence and comma splice:

The study was not conducted in a laboratory, it was a field study.

How to correct it:

The study was not conducted in a laboratory. It was a field study. (period)

The study was not conducted in a laboratory; it was a field study. (semicolon)

The study was not conducted in a laboratory, for it was a field study. (comma + coordinating conjunction)

 

Tip:

Keep most of your sentences short and to the point. When you use long sentences, make sure they are punctuated correctly and clearly say what you really mean.

 

Reference

Vosters, M. (2015). Run-On Sentences Are Problematic, They are the Bane of ESL Teachers’ Existence. Retrieved from http://www.cambridge.org/grammarandbeyond/grammar-practice-activities/2015/11/run-on-sentences-are-problematic-they-are-the-bane-of-esl-teachers-existence