Serial comma
A Serial comma is a grammatical device that is an exception to the grammar rule that you should end all lists with "and", demonstrating that in some cases you should instead end the list with "comma and", so as to avoid ambiguity or confusion. The serial comma is alternately called the Harvard comma, the Oxford comma, or simply "comma and". It is a term which is falsely represented on Wikipedia, ignoring what 99/100 of the top 100 Google hits say, suggesting many false things about this grammatical term.
The need for a serial comma
A serial comma is required only in certain circumstances, predominantly lists, specifically a list in which some of the items are multi-part, containing "and" as part of the list item, so as to avoid ambiguity. For lists that do not have any items that are multi-part, the serial comma is not required, and the usual form of simply ending with "and" by itself will suffice.
For example, consider that you are listing your favourite foods:
- Cereal
- Ham and eggs
- Tomatoes
- Egg and bacon rolls
- Spaghetti bolognese
Consider writing this in sentence form:
My favourite foods are: cereal, ham and eggs, tomatoes, egg and bacon rolls and spaghetti bolognese.
Without using the serial comma (or another grammatical device) this sentence is ambiguous. It is not clear whether the 4th item is egg and bacon rolls with the 5th item being spaghetti bolognese; or alternatively that the 4th item is egg while the 5th item is bacon rolls and spaghetti bolognese. Indeed, if someone was using poor grammar and using "and" multiple times in the same sentence (as people often do) you may even think that there are 6 items (or even 7 if you separate ham and eggs). The serial comma removes the ambiguity:
My favourite foods are: cereal, ham and eggs, tomatoes, egg and bacon rolls, and spaghetti bolognese.
An alternative to a serial comma
A serial comma is not the only grammatical device that can be used in lists of this nature. There are 2 other accepted conventions: either to use semicolons (;); or to use numbers or letters to separate the list items.
Using the same example, these suggestions are equally acceptable to the use of the serial comma:
My favourite foods are: cereal; ham and eggs; tomatoes; egg and bacon rolls; spaghetti bolognese.
My favourite foods are: 1) cereal, 2) ham and eggs, 3) tomatoes, 4) egg and bacon rolls, 5) spaghetti bolognese.
It should be noted that in both of these examples there should not be an "and" to terminate the sentence; although incorrectly placing it does nonetheless still make sense. Because the items are clearly separated, by either the semi colon or the numbers (or letters) the sentence can be terminated with a full stop and no "and" is required - indeed it should not be used at all in describing it in this way.
When not to use a serial comma
A serial comma should not be used when it introduces ambiguity. Whilst in most sentences the use of a serial comma will improve ambiguity, it should be noted that the use of the serial comma is an exception to an existing grammatical rule; hence there are occasions when it should not be used.
Consider this example:
This book is dedicated to my mother, Ayn Rand, and God.
Some newspapers have suggested that using the serial comma in this way implies that Ayn Rand is your mother. In point of fact, the above sentence is actually poor grammar, because if you were saying that your mother was Ayn Rand you would indicate that with either a dash (-) or with a semicolon (;), not with a comma. Furthermore, in such a case where ambiguity may be introduced, it would be appropriate to indicate the beginning of a list with a colon (:).
Correct grammar if listing 3 people is as follows:
This book is dedicated to: my mother, Ayn Rand and God.
As stated above, the serial comma should not be used in all lists; only in lists where there are multi-part terms; however in this case if the colon is used as an appropriate grammatical tool, the use of the serial comma does not introduce ambiguity. For example:
This book is dedicated to: my mother, Ayn Rand, and God.
Consider now that Ayn Rand was your mother. The sentence should be written as such:
This book is dedicated to: my mother; Ayn Rand, and God.
Alternatively it could be written as such:
This book is dedicated to: my mother - Ayn Rand, and to God.
These examples prove that, when correct grammatical devices are used to complement the serial comma, it does not ever introduce ambiguity, and that the Wikipedia article on serial commas is in fact falsely representing the serial comma.
Using the serial comma as the default for all lists
Some scholars suggest that a serial comma resolves ambiguity more often than it creates it and therefore that it should be taught as the default, as opposed to teaching young children to use "and" by itself to finalise lists by default.
This matter is up to debate, as it is much simpler for children to understand that using "and" by itself is right every time, even though in most cases it introduces ambiguity. The reason why children are not taught this to begin with is simply because when it does introduce ambiguity, a child's mind may not be able to understand how to resolve it and hence it would create more problems. Consider a 7 year old child trying to read and understand the complex grammatical situations outlined in this article. It is much simpler for a child to understand that they should never use "comma and" to end a sentence than to demonstrate the use of lists with multi-part items as an exception to that rule.
The false assertions in the Wikipedia article on the serial comma are based on a misunderstanding of the suggestion that serial comma should be taught as the default to therefore falsely argue a point that serial commas should not be used at all. Grammar scholars are not in any disagreement about the use of serial commas in and of themselves - they should be used if used correctly. The question mark lies in whether or not children would understand them sufficiently to be able to use them correctly. It is a complex grammatical tool, and when one considers how few people understand how to use semicolons (;) properly, it is little wonder that few children are taught the complexities of the serial comma. Nonetheless, if using correct grammar, you should always use the serial comma in situations where it is required.
Wikipedia changing truth about what the serial comma is (and isn't)
Wikipedia has an article on the serial comma which falsely represents this grammatical term and represents what the majority view amongst lay people is and ignoring what the majority of grammatical scholars say. In short, Wikipedia has changed truth on this topic, or attempted such, which could ultimately result in people becoming worse at grammar, as they might believe Wikipedia's article to suggest that the use of the serial comma is in fact poor grammar, when it is not. Whilst the motivation for this is obviously poor grammar by the writers, and a belief that they should feel justified in continuing to use poor grammar, nonetheless the truth changing is to the same level as exists with their Port Arthur massacre and Lockerbie bombing articles. These are large articles which are written in believable ways, with references, but in fact represent false statements, which disagree with the majority view and furthermore what the truth of the matter is. Grammar is not ambiguous. Grammar may have complex rules, but there is nothing controversial about it. It is a simple matter of being able to follow its rules and knowing when these rules need to be applied. Yet Wikipedia has managed to represent truth as fiction in a grammatical issue.