When we are trying to communicate complicated ideas, it is important to be specific. One way to ensure that you will not be misunderstood is to look at your use of 'scope'. 'Scope' refers to which words go with which to form a 'sense unit' in a sentence; for example, which nouns are covered by a particular verb or preposition. Often, poor punctuation or poor sentence construction messes the scope up. Scope isn't easy to explain, but you can get a handle on it once you have seen a few examples of how it works. We hope the following will be helpful.

Several grammatical devices help to indicate scope, but a big player is the comma. On our page Punctuation pauses, we talked about commas separating items in a list, but they also have a much wider structural function.

Because of this function, the use, or non-use, of commas can change the meaning of a sentence by altering the scope of one or more of its elements. Take the list in the following sentence:

She likes cool clothes and guys.

She likes cool clothes, and guys.

In the first example, the young lady likes cool clothes and cool guys; in the second, she's not quite so fussy. The comma restricts the scope of the word "cool" to just the clothes.

In the next example, the word "firing" is affected:

An imitation firearm is not designed for firing, and is not capable of firing, rimfire ammunition.

An imitation firearm is not designed for firing, and is not capable of firing rimfire ammunition.

In the first sentence, the commas around the clause "and is not capable of firing" indicate that the clause 'interrupts' the sentence and that the first instance of "firing", as well as the second, should be read with "rimfire". In the second sentence, the fact that there is a comma after the first instance of "firing" and no comma after the second indicates that only the second should be read with "rimfire"; that is, that the first instance of "firing" is absolute - an imitation firearm is not designed for firing any kind of ammunition. Without any commas, the sentence is ambiguous.

The following sentence shows how a lack of punctuation can contribute to ambiguity:

Recent developments include the revision of the corporate plan and the policy and development document that will give guidance to the directors, manager and staff.

What are the recent developments?

Perhaps they are the policy and development document (the one that's giving the guidance) and the revision of the corporate plan. In that case, we should say: Recent developments include the revision of the corporate plan, and the policy and development document that will give guidance to the directors, manager and staff. Or we could reverse the order: Recent developments include the policy and development document that will give guidance to the directors, manager and staff, and the revision of the corporate plan. In each case, note the use of the comma to separate the two developments.

On the other hand, the recent development could be the revision of both the corporate plan and the document, and this revision will give the guidance. Recent developments include the revision of the corporate plan, and of the policy and development document, that will give guidance to the directors, manager and staff. (Note the repetition of "of" to make it clear that both the corporate plan and the policy and development document are being revised. Repeating prepositions in this way is another way of indicating scope.)

These are just two of the possible meanings of the sentence. Can you think of others?