Hyphens, En Dashes, Em Dashes

Q. CMOS does not mention uses of the en dash for conflict or connection, as in “the liberal–conservative debate” or “the Radical–Unionist coalition.” Should it be inferred that CMOS opposes such uses?

A. CMOS would never oppose the consistent application of sound editorial logic, but we try to tailor our recommendations to serve both editors and readers. En dashes bump up against the limits of this goal. Editors tend to love them, but readers who haven’t been editors or proofreaders may not even notice them. If Chicago has resisted adding the sense of “between” or “and” to the more common use of the en dash as “to,” that’s the primary reason (see CMOS 6.80).

Because we do see the value of using an en dash in a phrase like “Ali–Frazier fight” or “Epstein–Barr virus.” Those dashes signal that you’re not referring to a fight or a virus that involves somebody with a hyphenated last name. And we wouldn’t want a “liberal–conservative debate” to be read as a debate about conservatives who are liberal, as a hyphen might imply. But if readers won’t get this from those en dashes (most of us—even those of us who can discern an en dash from a hyphen—will rely on context to figure out the intended meaning), is it worth an editor’s trouble to apply them?

True, we already take the time to convert hyphens to en dashes in number ranges, mostly because we know that “99–100” is a hair more legible than “99-100.” But pattern matching makes this easy to do. And we usually replace a hyphen with an en dash in “pre–Civil War” and the like—in the possibly vain hope that readers are more likely to see at a glance that it’s not a war that’s “pre-Civil.”

But we would need to be confident that more readers have become en dash literate before adding to our existing recommendations. If that ever happens, Chicago’s recommended uses for the character also known as Unicode 2013 may end up expanding.