Hyphens, En Dashes, Em Dashes

Q. I work as an editor, and we use CMOS as our primary source. My boss recently told me to hyphenate “machine-scored” in “the items were machine-scored,” because of a rule she cited about compounds formed with a verb. I can’t find a rule like this in CMOS. Is the hyphen Chicago style?

A. Chicago doesn’t require a hyphen in “machine scored” unless it serves as a modifier before a noun (e.g., “a machine-scored test”); after a noun, as in your example, the hyphen would be omitted. See the hyphenation guide, section 2, “noun + participle” (at CMOS 7.89). Compare “air-conditioned,” which is hyphenated in all positions, and “handcrafted,” which is always closed. Those terms derive from the verbs “air-condition” and “handcraft,” respectively, which are listed as such in Merriam-Webster (see also “phrases, verbal” in section 2 of the guide in CMOS).

The verb “machine score,” on the other hand, isn’t in Merriam-Webster. But that doesn’t mean your organization can’t choose to hyphenate it as a matter of house style. If you do—a decision that might make sense, for example, as the style for a company that routinely scores standardized tests and therefore uses the term more often than the average writer or publisher—then hyphenate it as a verb and as an adjective, in all positions in a sentence. For the noun, you could use “air conditioner” and “air-conditioning” as your models, leaving only “machine scorer” open.