Im writing a PhD research article on psychology. Im describing a number of formulation categories, each of which has been constructed using a particular way of explaining things, we call these ways "tools". As I`m describing the categories and the numbered tools related to them, I would prefer to write: "This category was constructed using the tool 2, X". I think the comma before the name of the tool is necessary. My professor insists on writing "This category was constructed using the tool 2 X", without comma. Which one is right?

  • Your professor is right, the comma is mandatory. Without it, the sentence reads as if the name of the tool were not "X" but "2 X". As an aside, "`" is the grave accent. It is a letter part, not a punctuation mark. Do not misuse it as an apostrophe. That's like replacing a b with a d. They might look very similar, but they don't mean remotely the same thing. Indeed, as you can see, the formatting of your post is completely broken just because of that. – RegDwigнt Nov 9 '14 at 18:37
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    @RegDwigнt - You appear to have confused the professor with the questioner. It is the professor who doesn't think the comma is needed, not the questioner. If the comma is mandatory, the professor cannot be right. – Erik Kowal Nov 9 '14 at 18:47
  • Where is the tool defined? – Andrew Lazarus Nov 9 '14 at 18:56
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    If X is the name of tool #2 (the only way I can interpret the above) then I'd probably write "This category was constructed using tool #2 (X)." – Hot Licks Nov 9 '14 at 22:35

With out without a comma, the meaning of using the tool 2, X is not clear. The definite article does not help. Assuming that 2 is the position on a list and X the name, these are possible:

...using tool 2, X

... using tool #2, X

... using tool No. 2, X

All of these have a necessary comma.


Yes the comma is necessary. If you wish to avoid it: "...using X (the second tool) ...", or"

Also in your example "This category was constructed using the tool 2, X" What is the purpose of the definite article? It almost implies that the tool is named 2X, and that your comma is therefore misplaced.


Commas are often used in writing to indicate what in speech would be a meaningful pause — that is, not only an extra moment of silence, but also the subtle change in intonation of the words spoken in order to convey the overall meaning.

In computer programs, we use commas to indicate separation of properties, e.g. 'first name, last name, address'.

This sentence refers to two separate properties: the name of the tool, and its position in a list.

The lack of a comma in a sentence like "We will use tool 2 X" gives no indication of the pause that would be needed in speech to indicate its position as distinct from its name.

Worse, if a tool called '2X' was created to indicate the doubling of some condition of X (perhaps to make an output clearer), you might have to speak of using 'Tool 2 X and tool 5 2X', which would generate considerable confusion.

However, I'm going to toss out another possibility: why not eliminate the problem altogether by not mentioning X's position on the list at all? Are the numbers important, or is the order arbitrary?


I suppose that in your article, at some point, there is a numbered list of tools with associated names or descriptions (the X). So, tool 2 and X are just alternate ways of identifying a specific tool.

If the sentence "This category was constructed using the tool 2, X" were sufficiently close to the list there would be no need for adding the X: "This category was constructed using tool 2" would be sufficient. Adding the X can be useful if the tool list is far from the sentence; in this case, since tool 2 and X are alternate names for the same thing, a comma is necessary.

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