There are a number of simple steps you can follow in order to check the use, non-use, or over-use of your comma. The most common simple rule we all know about the comma is the one that causes the most confusion. We all know that the comma is used to signal a break in the flow of the sentence. The problem with this rule is that breaking the sentence flow is quite complex. However, there are some recurring patterns.
Commas can be used to:
- Separate extra information from the main idea of the sentence
- Separate linking words from the main idea of the sentence
- List things, concepts, events, ideas, etc.
- Resolve ambiguity.
We can translate these rules to the following 6 cases when checking your comma.
1. Extra information at the beginning of a sentence
E.g.: Generally, most research has failed to make an impact.
In this study, the author examined over 1600 lakes.
If he knew who the writer was, he didn’t tell.
The introduction parts of these examples set off the main subject and verb of the sentence that follows. They can be small and large, but they are never a complete thought. The only purpose they have is to introduce the main idea that follows.
2. Extra information elsewhere in a sentence
E.g.: The University of Tartu, which is located in south Estonia, is the oldest university in Estonia.
The sample, which was taken from library, contained both old and new books.
The results of our study were, however, inconclusive.
Extra information takes many forms and commas are not always needed. You have to be cautious. To test if you need commas, consider removing the parts in between commas. If the sentence still works and makes sense, the commas are in the right place.
3. Small linking words (for, and, nor, but, or, yet, so)
To remember these small linking words use the mnemonic FANBOYS. What these words do is connect. They can connect words, phrases, and sentences.
E.g.: The text is almost revised and submitted.
The samples are kept in the laboratory or in the refrigerator.
The text has been checked for punctuation, so it must be easy to read.
Put simply, what you need to remember is the following: 1) if the group of words following FANBOYS do not make a complete thought (sentence), do not use a comma. If the group of words following FANBOYS make a complete thought (sentence), use a comma.
4. Other linking words and phrases
We also use linking words like however, therefore, besides, thus, finally, etc. to connect our ideas in sentences. The difference between these and FANBOYS is that these are punctuated differently.
E.g.: The results of our experiment were inconclusive; therefore, further research is needed.
These linking words and phrases are usually used to express an additional thought. This happens between two separate complete thoughts (sentences). In this case we can do two things. The example sentence above adds a semi-colon after the first complete thought, and a comma after the linking word or phrase (which is now more like an introduction at the beginning of a sentence: see point 1). We can also just separate the two sentences with a full stop.
5. Listing items in a sentence
In writing we often make lists. Take the following examples:
The Revolution was prompted by the bankruptcy of the kingdom, heavy taxation on the lower classes and the disparity between the living conditions of the classes.
Many native animals have symbolic significance, including the emu, the kangaroo, the wombat, the echidna, and the platypus.
When the list is not a complex list (items which also contain commas or dots) we separate them using the comma. The difference between these two examples is the comma before and in the second example. In English academic writing it is very common to add a comma before and and or in a list which contains three or more items. It is never wrong, but you have to be consistent.
6. Watch out for the comma splice!
We can never join two complete thoughts (sentences) together with a comma. Take the following example:
Johnson (2008) conducted research, it was well organized. – incorrect
We also can’t connect them with nothing. We can make two separate sentences and we can also apply step 3 (small linking words). We can also apply step 4 (other linking words and phrases). When applying these solutions, think carefully about the comma!
These tips may work in most cases when you’re looking up and figuring out your comma, but unfortunately, especially in academic writing, we tend to complicate matters. But, do not fear, there are many more punctuation marks which offer a solution. If all else fails, you are more than welcome to drop by the Centre of Academic Writing and Communication (AVOK), Jakobi 2-131, or contact us at firstname.lastname@example.org.