Writing Sentences: Sentence Errors: Run-on sentences

A run-on sentence is a sentence which includes more than one complete idea: it is actually a series of sentences run together that are joined by commas instead of full stops. An example of a run-on sentence is:

After water is released from the dam it is important that it is able to move easily downstream. In order to improve this movement, channel improvements must sometimes be made, this can involve straightening bends and removing brush debris or hazards from the channel.

The highlighted section of this sentence is actually a complete idea in itself. It should stand as a sentence on its own rather than being connected by a comma to the preceding clause. The sentence could be repunctuated more correctly in 2 ways: by adding a full stop to make the run on sentence a complete sentence by itself or by adding a colon to introduce the channel improvements.

After water is released from the dam it is important that it is able to move easily downstream. In order to improve this movement, channel improvements must sometimes be made. This can involve straightening bends and removing brush debris or hazards from the channel.

After water is released from the dam it is important that it is able to move easily downstream. In order to improve this movement, channel improvements must sometimes be made: this can involve straightening bends and removing brush debris or hazards from the channel.

Run-on sentences could also be repaired by making part of the preceding sentence a relative clause through the introduction of a relative pronoun such as which and making the run-on sentence part of the main clause:

Run-On Sentence with preceding main clause	Corrected Sentence (with relative clause and main clause)
Passive euthanasia is withdrawing or withholding life-sustaining treatment from a terminally ill and suffering patient, it seems more easily justified than killing such a patient.	Passive euthanasia, which is withdrawing or withholding life-sustaining treatment from a terminally ill and suffering patient, seems more easily justified than killing such a patient.

Here is another example of a run-on sentence:

The manager should try to be more aware of group norms , he or she should also try and find out which aspects of the organisational culture are counter-productive for group efficiency.

This run-on sentence is a complete idea that can stand alone as a sentence in its own right, just as the preceding sentence can. The run-on sentence can thus be repaired by repunctuating it as a separate sentence:

The manager should try to be more aware of group norms. He or she should also try and find out which aspects of the organisational culture are counter-productive for group efficiency.

To summarise: Run-on sentences occur when complete stand alone ideas have not been properly punctuated as sentences. They can be repaired by either:

repunctuating and making two separate sentences

creating a relative clause.