Q. CMOS 5.201 says that “compare with” should be used for literal comparisons and “compare to” for poetic or metaphorical comparisons. Does the same rule apply to “comparable”? My organization enforces “comparable with” because we follow CMOS and publish material that’s not remotely poetic. “With” sounds odd to me, though; Google Books Ngram shows that “comparable to” is used more than six times as often, and it’s been the more popular variant for almost 100 years [that’s true when British English is considered together with American English; in British English, “comparable with” was the more popular form until the mid-1970s.—CMOS editor]. Can I make a case for sticking with “comparable to”?
A. Yes, you can pair “comparable” with “to” rather than “with.” First, note that “compare” is included not only in the list at paragraph 5.201 (which covers words and the prepositions they’re paired with); it’s also covered in the usage glossary under CMOS 5.254, which has this to say: “To compare with is to discern both similarities and differences between things. To compare to is to liken things or to note primarily similarities between them, especially in the active voice.” The example often cited as evidence of the latter is a line from Shakespeare: “Shall I compare thee to a summer’s day?” (Sonnet 18).
But “comparable” generally means “similar,” and it’s not a verb (so it can’t be said to be in the active voice). Even when it means “capable of or suitable for comparison” (the older sense of the word, as recorded in Merriam-Webster), it still carries the sense of likeness. True, there was a clear preference for most of the twentieth century in British English for the phrase “is not comparable with” (for things that are not alike), but for whatever reason (maybe that wording is too far removed from Shakespeare?), that’s not the case anymore.