A common failing among authors and editors is the incorrect use of i.e. and e.g., that is and for example, respectively.
Consider this example: “When I apply color (i.e., cobalt blue), the sky seems wrong.” I see hundreds of examples of this use in my editing work and wonder what exactly does the author mean. It should be obvious and clear what is meant, but if you think about it, the sentence is as clear as mud.
In fact, I have a standard query to the author that I use when I see misuse of i.e., which query is:
AQ: Do you mean e.g. rather than i.e.? When the items are only examples and the list is not all inclusive, e.g. is used. If the listed items are all the possibilities, then i.e. is used. If i.e., is correct, consider removing material from parens and making it a proper part of the sentence.
(I use EditTools’ Insert Query macro to insert standard queries into a manuscript without having to rewrite them each time. I currently have a number of “standard” author/editor/compositor queries preformulated, one of the ways I increase my efficiency. The Insert Query macro was discussed earlier on American Editor in The Business of Editing: Author Queries.)
Often this query is ignored, because the author doesn’t really understand the implications of the choice between i.e. and e.g., and because authors generally don’t want to rewrite what they consider near perfect, if not perfect.
In the example, does the author mean “When I apply the color cobalt blue, the sky seems wrong,” or does the author mean “When I apply a color such as cobalt blue, the sky seems wrong,” or does the author mean “When I apply a color, for example, cobalt blue or pale pink, the sky seems wrong”? Is cobalt blue the color under discussion or just an example of several colors under discussion?
That’s right; the difference between i.e. and e.g. is the difference between a limited, definable number and many. Yet many authors and editors fail to distinguish between them or to consider that there may be some difference in meaning. That is (i.e.) is limiting whereas for example (e.g.) is expansive. Although authors use them interchangeably, they are not interchangeable.
Another way to distinguish between the two phrases is to view i.e. as a phrase to introduce a clarification of preceding text whereas e.g. introduces representative, but not exclusive, examples. Yet, again, the matter comes down to the basic thrust of grammar — to make words meaningful and comprehensible.
Of equal importance is the question whether i.e. should ever be used in the main text (as opposed to, e.g., in footnotes and sidebars). For the most part, I encourage authors to rewrite their sentences to eliminate the parenthetical i.e. because doing so can only lead to greater clarity. I confess that many of my colleagues disagree with my view, but I fail to see what is gained by using i.e. in the primary text.
Because i.e. acts as a limit — there are only these and no more — it is easy to rewrite the sentence. I can as easily write “When I apply the color cobalt blue, the sky seems wrong,” or “When I apply the colors cobalt blue and pale pink, the sky seems wrong,” as I can write “When I apply color (i.e., cobalt blue), the sky seems wrong,” or “When I apply color (i.e., cobalt blue and pale pink), the sky seems wrong.” And when I rewrite the sentence there is no doubt about what I mean.
The clarity that is garnered by rewriting is important to reader understanding. Consider a medical text in which the author uses the parenthetical i.e. Some readers will interpret it as meaning only the items listed in the parenthetical, whereas others will construe the items as examples of which there are many yet to be named. If the latter is correct, the readers who apply the former interpretation will have misconstrued the sentence and missed important knowledge. Similarly, if the former is correct, those who made the latter interpretation will also misconstrue the sentence and think that the information applies more broadly than it does.
Just as it is important to note that the parenthetical i.e. is often used incorrectly, it is important to note that there are times when its use is very appropriate. As with everything else, it all depends on context. A professional editor needs to think about every i.e. and query each one that is questionable. An author needs to think about why he or she is using i.e. instead of merging the information into the primary text where it belongs. (As you may recall, this is also my view regarding the misuse of footnotes and endnotes, which was discussed on An American Editor in Footnotes, Endnotes, & References: Uses & Abuses.) Readers need to stop and think about every i.e. and what it really means in the context.
Editors and authors need to apply the basic rules of grammar — is the meaning clear and understandable or does interpretation, especially reader interpretation, play a role — when deciding to use the parenthetical i.e. But above all, editors and authors need to make sure that i.e. and e.g. are being used properly, the former for the limited (that is), the latter for the many (for example).