Twice in the past week, people have asked me about “compare to” and “compare with.” What’s the difference, they wondered. How do you know which one to use?
The subject is a sore spot for me. For years, my job was to edit press releases, many of them for companies reporting quarterly earnings. Every time these companies compared their quarterly income or their dividends or their costs per share “to” the previous quarter, I’d change it to “with,” certain I was fixing an error.
So it stung when, eventually, I learned that the rule of which I’d been so sure wasn’t a rule at all.
The idea I was operating under was that “compare to” means to liken and “compare with” means to examine to discover differences as well as likenesses. Therefore, you might compare someone to a summer’s day, but you’d discuss how your first-quarter earnings compare with last quarter’s.
Bossy language commentators have, for years, peddled this rule. Here’s Theodore M. Bernstein’s 1965 “The Careful Writer.”
“The choice of ‘to’ or ‘with’ to follow ‘compare’ is not a matter of indifference. When the purpose is to liken two things or to put them in the same category, use ‘to.’ When the purpose is to place one thing side-by-side with another to examine their differences or their similarities, use ‘with.’”
If you follow this guideline, you get good results. To say “Shall I compare thee to a summer’s day,” as Shakespeare did, simply sounds better than “Shall I compare thee with a summer’s day.” Putting a modern spin on this phrase doesn’t change this: “Can I compare you to a summer’s day” sounds better than it would with “with.”
So what’s the problem? It’s that Bernstein and a host of others who laid down this law went too far. Just because one preposition sounds better than another doesn’t mean one of them is wrong.
Prepositions have a unique function in the language. Unlike other parts of speech that are governed by strict laws of syntax, prepositions are sometimes governed solely by idiom.
For example, it’s ungrammatical to say “Us go to the store,” but it’s not ungrammatical to say “I differ at him.” That first example violates grammar laws because those laws say that subject pronouns like “we” should be the subjects of verbs, not object pronouns like “us.”
“Differ at” is, obviously, a wrong way to say “differ with.” But its wrongness has nothing to do with the rules of syntax. Instead, it’s bad because that’s just not how people say it. This is what we mean by idiom. It’s like precedent. And the dynamics of idiom are why it’s just as right to say “differ from” as it is to say “differ with.”
Bernstein himself agreed emphatically on this point: “The proper preposition is a matter of idiom,” he noted in the “The Careful Writer.” Adding that, when a preposition doesn’t come naturally, sometimes “the only thing to do is to consult three knowing friends and get a consensus.” So by his own logic, “compare with” can’t be written off as ungrammatical.
If people customarily use “compare to” and “compare with” as interchangeable, then they are. But do they?
According to Merriam-Webster’s Dictionary of English Usage, people tend to follow the stickler rule in the active voice. That is, they use “compare to” to show how one thing is like another and they use “compare with” to explore ways in which they might differ.
In the passive voice, however, “compared to” is often used as a substitute for “compared with.” Think of the sentences “Compared to you, I’m a fast runner” and “This year’s earnings, compared to last year’s, are somewhat encouraging.”
Both those sentences defy the stickler rule, yet both sound fine, which means both are OK.
JUNE CASAGRANDE is author of "It Was the Best of Sentences, It Was the Worst of Sentences." She can be reached at JuneTCN@aol.com.