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What is a comma splice?

A comma splice happens when a comma inappropriately links two independent clauses.

She’s an outstanding student, she’ll go far.

The comma here may well represent how people say the two clauses out loud. However, in any formal or academic writing, to use it is incorrect; it is a mistake that can make your writing seem careless or amateurish.

Why ‘splice’?

If you splice something together, you join two things that were originally separate. The comma splice splices together two clauses that are each complete in their own right.

Examples and solutions

[In response to an email ‘I’ll get back to you tomorrow’]

That’s absolutely fine, thanks for the holding email!

There are two main reasons for avoiding Greece in the summer, [comma splice] it can be extremely hot, and popular locations can be wildly overcrowded.

There are four ways of avoiding the comma splice:

(1) Make the two clauses into separate sentences:

That’s absolutely fine. Thanks for the holding email!

There are two main reasons for avoiding Greece in the summer. It can be extremely hot, and popular locations can be wildly overcrowded.

This solution generally works best when the two clauses are of a certain length. As two sentences, the first example sounds a bit terse or even brusque. Making the second example two separate sentences weakens the obvious link between them.

(2) Use a conjunction such as and or but, or as, because, so, if there is a causal connection.

This works well when the meaning of the second clause only loosely relates to the first:

That’s absolutely fine and thanks for the holding email!

For our second example, it doesn’t work very well, since what follows the first comma is not the cause of what is said in the first clause.

X There are two main reasons for avoiding Greece in the summer, because it can be extremely hot, and popular locations can be wildly overcrowded. 

(3) Use a semicolon (;)

It links these two clauses elegantly and simply:

That’s absolutely fine; thanks for the holding email!

One of the main functions of the semicolon is to divide two closely related clauses that balance each other (often each contains a finite verb). So, the second example could be re-punctuated as:

There are two main reasons for avoiding Greece in the summer; it can be extremely hot, and popular locations can be wildly overcrowded. 

(4) Use a colon (:)

One of the colon’s principal functions is to present the part of the sentence following it as an explanation, expansion, or result of what comes before it. It works very nicely for our second example:

There are two main reasons for avoiding Greece in the summer: it can be extremely hot, and popular locations can be wildly overcrowded.

Test yourself

Which of these sentences contains a comma splice?

  1. After I finished my breakfast, I decided to go for a stroll.
  2. I love avocados, they’re my favourite starter.
  3. I couldn’t afford the model of car I really wanted, so I bought the next one down in the range.
  4. Oxford can get bitterly cold in winter, it surprises some people.
  5. Given recent research, it is highly likely that a cure will be found within the next couple of years.

 

2 and 4 contain comma splices.

In the other three, the comma is correctly used. In 1, the first part is a subordinate clause. In 3, the two clauses are linked by the conjunction so. In 5, the first clause is another subordinate clause containing a past participle.

 

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You may also be interested in:

Split infinitives

Dangling participles

 

 

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