What a Run-On Sentence Is
A run-on sentence occurs when two or more independent clauses are joined without appropriate punctuation or a coordinating conjunction. The result is a sentence that keeps going past its natural endpoint, forcing the reader to do unnecessary cognitive work to determine where one idea ends and another begins. Run-on sentences are common in Malaysian postgraduate theses — particularly in methodology and discussion chapters where writers are trying to connect multiple ideas quickly — and they undermine the clarity of even well-reasoned arguments.
The most common form is the comma splice, where two independent clauses are joined by a comma alone: “The sample was small, this limits generalisability.” A comma is not strong enough to join two independent clauses. The correct options are a full stop (“The sample was small. This limits generalisability.”), a semicolon (“The sample was small; this limits generalisability.”), or a coordinating conjunction with a comma (“The sample was small, and this limits generalisability.”).
Finding Run-On Sentences During Proofreading
Run-on sentences are best found through read-aloud proofreading. When you read a sentence aloud and your voice wants to pause or drop in pitch before the sentence actually ends, you have likely found a run-on. The natural speech pause point is where the full stop or semicolon should be.
A targeted search approach also helps. Search for sentences where a pronoun — “this”, “it”, “they”, “these” — immediately follows a comma without a coordinating conjunction between the two clauses. “The results were consistent, they support the hypothesis” is a comma splice. Searching for “, this”, “, it”, “, they”, and “, these” and reviewing each hit reveals comma splice patterns efficiently across the entire thesis. Not every instance will be a run-on, but the review process catches the majority.
Fixing Run-On Sentences Effectively
When you identify a run-on sentence, choose the correction that best serves the logical relationship between the two clauses. If the ideas are closely related and equally important, a semicolon is appropriate. If the second clause explains or expands the first, a colon may work. If the relationship is one of contrast, “however” or “but” with appropriate punctuation is clearest. If the ideas are relatively independent, separate them with a full stop.
Avoid correcting run-on sentences by simply adding a comma where there was none — this produces a comma splice rather than fixing the original run-on. The correction must either separate the clauses with a full stop or semicolon, or add a coordinating conjunction that makes the comma strong enough to join them. Proofreading your thesis for run-on sentences as a dedicated pass improves the grammatical precision of your academic writing and prevents the kind of readability disruption that accumulates invisibly across a long document.
