How to avoid a common comma error: the comma splice

How to Avoid a Common Comma Error: The Comma Splice

Comma splices and run-on sentences are common problems in business writing. So what are they?

They are both comma errors.

Comma splice

A comma splice occurs when you use a comma to join two independent clauses (also known as main clauses). An independent clause expresses a complete thought and can stand alone.

  • The train was late (independent clause)
    I walked to work (independent clause)
  • The train was late, I walked to work. (comma splice)
  • As a general rule, a comma is not strong enough to join two independent clauses.
  • You could correct this sentence with a semicolon, conjunction, dash or full stop.

The train was late; I walked to work. (semicolon)
The train was late, so I walked to work. (conjunction)
The train was late – I walked to work. (dash)

The train was late. I walked to work. (two sentences)

This error came to my attention, because I was reading business documents with a template that constrained word length. Towards the bottom of some pages, the number of comma splices increased, no doubt to fit more words on the page.

Having said that a comma splice is an error, a comma splice can be effective when used by accomplished writers.

Combining Clauses to Avoid Comma Splices, Run-ons, and Fragments

  • *The data are inconclusive the researchers will repeat their experiment.
  • *The data are inconclusive, the researchers will repeat the experiment.
  • *Since the data are inconclusive.

In academic writing, we often combine clauses to express complex ideas within one sentence.

We can link clauses with conjunctives, or words that illustrate the meaning between two clauses. If these words and punctuation marks are used incorrectly, sentence structure problems can occur, as illustrated in the three examples above.

In this handout, you will learn about different ways of combining clauses, and how to avoid comma splice, run-on, and fragment mistakes.  

Background

A clause is defined as a word grouping that contains a subject and a verb.

There are two kinds of clauses: independent clauses, which convey complete meaning and can stand alone as simple sentences, and dependent clauses, which do not express a complete idea on their own and must be paired with another clause. We use different conjunctive words and punctuation to connect these different types of clauses.

  1. Structuring Sentences with Independent Clauses
  2. OPTION 1:Use a comma and a coordinating conjunction
  3.  
  4. Example: The article was published in a peer-reviewed journal, so it is a credible source.
  5. OPTION 2: Use a semicolon
  6. Example: The article was published in a peer-reviewed journal; it is a credible source.
  7. OPTION 3: Use a semicolon, transition word, and comma
  8.  
  9. Example: The article was published in a peer-reviewed journal; therefore, it is a credible source.
We structure coordinating clauses in these ways to avoid creating run-on sentences and comma splices. A run-on sentence is a mistake that occurs when two independent clauses are combined without using any conjunctive words or punctuation marks. Our first example sentence at the beginning of the handout (The data are inconclusive the researchers will repeat their experiment) illustrates this problem. It is difficult to distinguish the two ideas, and the reader might be confused about the meaning of the sentence. A comma splice mistake can be seen in our second example (The data are inconclusive, the researchers will repeat the experiment). It incorrectly joins two clauses with a comma only. To form a grammatically correct sentence, a comma should be followed by a coordinating conjunction or changed into a semi-colon.
  • Structuring Sentences with Dependent Clauses
  • OPTION 1: Use a subordinating conjunction after the independent clause
  • Note: there is no punctuation before a subordinating conjunction when the subordinating conjunction is in the middle of the sentence.
  •  
  • Example: The chapter is dense because it is thorough.
  • OPTION 2: Start sentence with the subordinating conjunction and add a comma after the dependent clause
  • Example: Because it is thorough, the chapter is dense.
A fragment, as our third example shows (Since the data are inconclusive), is an incomplete sentence. Oftentimes, fragments occur when dependent clauses are not connected to an independent clause, but left to stand alone. (Learn more about fragments from the handout “Avoiding Fragments with Dependent Clauses”)

Information in this handout is adapted from Fawcett, S. (2007). Evergreen: A guide to writing (8th ed.). Houghton Mifflin Company.

Strategies

3 Common Comma Mistakes

The comma is one of the most abused and misused punctuation marks in the English language. The comma gives us the dreaded run-on sentence, the confusion of verb separation and odd sentence fragments, and—when missing altogether—some of the most hilarious misunderstandings in the grammar world.

The Run-On (and-on-and-on) Sentence

Is there anything more annoying than a run-on sentence, one that doesn't seem to ever end, and as one comma piles on another, without any break in sight, you begin to wonder what it is that you're even reading, as the point becomes less and less clear the longer you read, and the original subject gets lost in all these ceaseless, pointless, commas, because how can anyone think it's even possible to understand so many thoughts crammed in between two periods?

The run-on sentence, or comma splice, happens when a comma joins two independent clauses. An independent clause is a standalone statement. If both parts of your sentence make perfect sense all by themselves, do not use a comma. Use a period, a semicolon, or a comma plus a conjunction (if you really must have your comma).

See also:  Sentence fragments

The Missing Comma

“I'm sorry I love you.”

“I'm sorry, I love you.”

What Comma Splices Are and Why You Need to Avoid Them – Cite this for Me | Free Reference Generator – Harvard, APA, MLA, Chicago..

There are many new words and phrases we learn in school. For example, tetrahydrate, APA format, diaspora, and so forth.

The term “comma splice” is thrown around in English classes on a regular basis–no doubt you have heard this term a time or two in your school career.

Yet unless you took the time to study this common error and correct the places where a teacher or tutor pointed it out, you may not have realized what it is exactly.

That’s ok! Taking a little time out to look at what a comma splice is today will help you in future writing. We’re all on a journey of learning, and mastering the comma splice is just one step along the way.

Just What Is a Comma Splice?

The Oxford English Dictionary defines a comma splice as what “happens when a comma inappropriately links two independent clauses.” It goes on to explain that “If you splice something together, you join two things that were originally separate.”

First, it is important to understand what an independent clause is. An independent clause is a phrase with both a subject and a verb and can be used as a sentence by itself. When you join two independent clauses together with only a comma, you are circumventing proper end punctuation (a period, exclamation point, question mark, etc.).

Improve Your Writing

Table of Contents

In the following exercise you will be presented with a series of sentences containing a comma. You have to indicate whether you think that the sentence is an example of the comma splice.

1 I love eating fruit, it is one of my favourite things.
2 After visiting the cinema, we are intending to go to the pub.
3 After a couple of drinks, we enjoyed a lovely stroll along the beach.
4 There are many reasons to visit Greece, the beaches are lovely and the people are friendly.
5 I'll never be able to buy a house, prices these days are just ridiculous.
6 I can not afford a house in London, so I am moving to Sunderland.
7 This is a lovely cake, you must give me the recipe one day.
8 The computer in my room is old, but the carpet is ancient.
9 Given the lack of understanding among the general public, it is not surprising that many people are guilty of using the comma splice.
10 Hungary is an interesting country, the churches contain some of the finest frescos found anywhere in Europe.
  • Read more about the comma splice.
  • Find out more about the uses of the comma.
  • See a list of other grammar exercises.

Comma Splice Examples

A comma splice is a common grammatical error in English. Writers most often make this mistake when they are trying to “write by ear.” It's a common idea that a comma indicates a pause where a reader or speaker should take a breath, but simply adding commas when you feel a break is needed is not a reliable way to make sure you're punctuating your sentences correctly.

A comma splice is when two independent clauses are incorrectly joined by a comma to make one sentence. To avoid comma splices, you first need to be able to identify an independent clause.

An independent clause is a complete sentence that can stand on its own grammatically. To be a complete sentence, the clause must have both a subject and a verb. For example:

I went to the mall.

This is an independent clause because it has both a subject (“I”) and a verb (“went”). This forms a complete sentence.

Not all clauses with a subject and a verb can stand alone, however. A dependent clause often begins with a word that is meant to connect it to another sentence and cannot stand alone as a complete sentence. For example:

When I went to the mall

Because “when” is added to the clause, it is no longer a complete sentence on its own. This dependent clause would need to be connected to another clause to make it a complete sentence.

It is incorrect to join two independent clauses with a comma. This error is called a comma splice. For example:

I went to the mall, Jane was there.

“I went to the mall” is an independent clause that can stand alone as its own sentence. “Jane was there” is also an independent clause. It is grammatically incorrect to link these two sentences with a comma.

There are three ways to fix a comma splice. First, you can split the part before the comma and the part after the comma into two complete sentences with a period (you could also use a semi-colon for a less defined split). Here's how to fix our example from above:

I went to the mall. Jane was there.

  • Second, you can join two independent clauses by adding a coordinating conjunction such as “and” after the comma. For example:
  • I went to the mall, and Jane was there.
  • Finally, you can change one of the independent clauses to a dependent clause by adding a subordinating conjunction. For example:
  • When I went to the mall, Jane was there.
  • I went to the mall because Jane was there.
See also:  When is it ok to be redundant?

Note that if your dependent clause comes first, you must use a comma to join the two clauses. If your dependent clause is second, no comma is required.

Examples of Comma Splices and Corrections

Check your understanding of comma splices by studying the examples and corrections below.

Correcting by Making Two Sentences

Error Correction
I love going to the movies, it's so fun. I love going to the movies. It's so fun.
She took the boy's cookies away, that was mean. She took the boy's cookies away. That was mean.
The teacher was angry, the students were too loud. The teacher was angry. The students were too loud.
I think he's in love, he acts so weird now. I think he's in love. He acts so weird now.
She was sad when the cat ran away, she doesn't want to get a new one. She was sad when the cat ran away. She doesn't want to get a new one.
We went to the store, we bought milk. We went the to the store. We bought milk.
I often walk the dogs on the beach, they love splashing in the waves. I often walk the dogs on the beach. They love splashing in the waves.
I can't wait to go on vacation, it will be hot and sunny. I can't wait to go on vacation. It will be hot and sunny.

Correcting by Using Coordinating Conjunctions

Error Correction
I love going to the movies, it's so fun. I love going to the movies, for it's so fun.
She took the boy's cookies away, that was mean. She took the boy's cookies away and that was mean.
The teacher was angry, the students were too loud. The teacher was angry, for the students were too loud.
I think he's in love, he acts so weird now. I think he's in love, for he acts so weird now.
She was sad when the cat ran away, she doesn't want to get a new one. She was sad when the cat ran away, but she doesn't want to get a new one.
We went to the store, we bought milk. We went the to the store and we bought milk.
I often walk the dogs on the beach, they love splashing in the waves. I often walk the dogs on the beach, for they love splashing in the waves.
I can't wait to go on vacation, it will be hot and sunny. I can't wait to go on vacation, for it will be hot and sunny.

Correcting by Creating a Dependent Clause

Error Correction
I love going to the movies, it's so fun. I love going to the movies because it's so fun.
She took the boy's cookies away, that was mean. When she took the boy's cookies away, that was mean.
The teacher was angry, the students were too loud. The teacher was angry because the students were too loud.
I think he's in love, he acts so weird now. I think he's in love because he acts so weird now.
She was sad when the cat ran away, she doesn't want to get a new one. Even though she was sad when the cat ran away, she doesn't want to get a new one.
We went to the store, we bought milk. We went the to the store where we bought milk.
I often walk the dogs on the beach, they love splashing in the waves. I often walk the dogs on the beach since they love splashing in the waves.
I can't wait to go on vacation, it will be hot and sunny. I can't wait to go on vacation as it will be hot and sunny.

Strong Sentences

Once you get used to asking yourself if the two parts of your sentence can stand alone as independent clauses, you'll be able to correct comma splices in your writing with ease.

To add interest to your written work, try varying the way you correct a comma splice so your sentences don't all sound the same.

When you master this trick, your English grammar will automatically improve.

The comma splice: how to avoid the most common punctuation error there is — Doris and Bertie Ltd

The full-stop – also known as the period – has several uses.

But it’s most often used at the end of a declarative sentence. That’s just a fancy way of saying a sentence that’s making statement. As opposed to asking a question or making an exclamation  – where you’d obviously use a question mark or an exclamation mark.

  • Now, to understand how to use the full stop correctly in a declarative sentence, you have to understand what a sentence is.
  • So let’s dial back a bit and ask ourselves: what is a sentence?
  • Here’s the usual dictionary definition:

A sentence is “A set of words that is complete in itself, typically containing a subject and predicate”

Let’s quickly unpack some of that grammar speak here. First of all, ‘subject’ means the person or thing that’s doing the action of the sentence.

See also:  The world of trigonometry

And ‘predicate’ means the part of the sentence that contains the verb – or the action word – and states something about the subject.

For example, in the sentence ‘Jamie eats’, Jamie is the subject, while the verb or action word ‘eats’ is the predicate.

But remember: the predicate is defined as the part of the sentence containing the verb. So sometimes the predicate might be longer as in: Jamie eats dinner. Here, the entire phrase ‘eats dinner’ is the predicate.

Or we could even say: Jamie eats dinner after eight o’clock each night. And here, ‘eats dinner after eight o’clock each night’ is the predicate.

Each of these three examples – Jamie eats, Jamie eats dinner, and Jamie eats dinner after eight o’clock each night – is a set of words complete in itself containing a subject and a predicate. So each is a full sentence.

It’s really important to understand this definition of a sentence, because probably the number one error I spot in people’s writing is not ending sentences with a full stop. Instead, they will often join two separate sentences with a comma.

This hugely common error is known as a ‘comma splice’. So let’s take a look at a real-life example of a couple of comma splices that I came across recently.

I’ve changed some of the details to protect the author, but this extract is from a sales letter. It has two full stops in it, but it actually needs four:  

I am from TTFN, a firm which specialises in corporate strategy advice, we currently advise many real-estate developers across both the UK and continental Europe.

We also advise the social housing, private equity and infrastructure sectors, I have attached a brochure for your reference.

  1. Let’s start with that second sentence – which is actually two sentences wrongly joined by a comma.
  2. If we take all the text before the second comma, we can see that it meets all the criteria for a sentence.
  3. First of all, it’s a set of words complete in itself: We also advise the social housing, private equity and infrastructure sectors makes total sense on its own.
  4. It also has a subject (We) and a predicate (the part of the sentence that includes the verb – also advise and so on).

Let’s also look at the text after that comma in the middle.

Again, it fulfills all the criteria for a sentence: I have attached a brochure for your reference is a set of words complete in itself – it doesn’t need anything else to makes sense.

And it has a subject (the I that’s doing the action) and a predicate (the part of the sentence that includes the verb – have attached a brochure for your reference).

So what we have here is two complete sentences. And in correct grammar, you cannot connect two separate sentences with a comma. You may see this habit a lot, but a full-stop would generally be considered the correct choice here.

Let’s look at the first sentence – which again, strictly speaking, is two sentences wrongly separated by a comma.

I am from TTFN meets the criteria of a full sentence. It is a set of words complete in itself and it’s made up of a subject (I) and a predicate (am from TTFN).

So we could put a full stop here instead of the first comma.

If we did that, the next sentence would read:

A firm which specialises in corporate strategy advice,we currently advise many real-estate developers across both the UK and continental Europe.

Again, this satisfies the criteria of a full sentence. We have a subject: A firm which specialises in corporate strategy advice, we. It’s obviously a little more complex than the previous subjects we’ve looked at.

But this entire phrase describes who’s doing the action.

You’ll recognise [from a previous lecture in the course] that comma as an appositive comma because A firm which specialises in corporate strategy advice refers to the same thing as we.

  • We also have a predicate – the part of the sentence containing the verb – in currently advise and so on.
  • So it would be more correct to put a full stop after TTFN, rather than a comma.
  • Another way of correcting the punctuation in this extract would be to replace the second comma with a full stop instead of the first comma, as in:

I am from TTFN, a firm which specialises in corporate strategy advice. We currently advise many real-estate developers across both the UK and continental Europe.

Again, we have two full sentences on each side of this full stop, and using a comma here instead of the full stop would generally be considered wrong.

In that last example, either of my suggested ways of punctuating the sentence would have been correct – it would just depend on your preference.

The only thing to remember is that if you’ve got two separate sentences, you mustn’t separate them with a comma. Instead, it’s correct to use a full stop.

This video is from my online course, Complete Punctuation: Novice to Pro, which will be published on 7 May. Subscribe below for a reminder and special introductory offer the moment the course goes live.

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