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A onefold decrease is quite enough, thank you

hat's wrong with the following statements?

  • The Mexican state of Jalisco is 15 times larger than neighboring Colima.

  • Covad's entry-level broadband service is four times faster than most modem connections.

  • A killer who commits his crime in Baltimore County is 26 times more likely to receive the death penalty than one in neighboring Baltimore City.

    The problem is that "times [blank]er" and "times more," while very common (the above examples are from my newspaper, The Washington Post), make no sense. Although we may understand the intended meaning, such phrasing confuses addition with multiplication and, at least when taken literally, contains a built-in distortion.

    The bottom line:

  • "Times" goes with "as [blank] as."

  • Percentages go with "[blank]er" and "more [blank]."

    "Times" is a multiplier. Two times one is two times as much as one. Think about how natural it is to say "twice as much as" and keep that in mind even when the numbers get bigger.

    "More" signifies addition. It and "[blank]er" usually work best with increases of less than 100 percent: In this state, today's high school students are 25 percent more likely to graduate than students were a decade ago. The governor's education budget is 25 percent higher than last year's allocation.

    Percentages can, of course, be used to indicate multiplication, and that is a common convention in references to investments and financial indexes: That birthday present of Microsoft stock appreciated 900 percent by the time he turned 18. To the non-business-page reader, however, it would be clearer to say the stock was worth 10 times as much.

    The built-in distortion stems from the literal meaning of "times more." Two hundred is twice as much as 100, but it's one time more. That's easy to see with this example, but when you think about "100 times more" or even "three times more," it's easy to think of such comparisons as synonymous with "100 times as much as" and "three times as much as," even though they literally mean "101 times as much as" and "four times as much as."

    In my experience, it's safe to assume that a writer is using the "times more" phrasing erroneously. When you see "100 times more," the intended meaning is "100 times as much as."

    A parallel ambiguity leads me to steer clear of "a [blank]fold increase." We hear and read and use
    "-fold" all the time, but do we even know what it means? For most of my career, I thought, well, a twofold increase would mean a 200 percent increase. One, plus an increase of two times as many, equals three. But one day it occurred to me: There are no "onefold" increases. "Twofold," as the dictionary says, means twice as much; the "increase" part is a hard-to-avoid redundancy. I thought I had made my peace with "-fold" when I came across a reinforcement of my original belief in
    "Words Fail Me," by the great Patricia T. O'Conner. So who knows? If she and I can't agree on what "-fold" means, that's an excellent reason to avoid it altogether.

    For an even worse distortion than "times more," think about "times less." More examples from my paper:

  • Student athletes subject to random drug testing at an Oregon high school were almost four times less likely to use drugs than their counterparts at a similar school who were not tested, according to a study by researchers at Oregon Health and Science University.

  • Mars is very cold and its atmosphere is a very thin blanket -- 100 times less dense than Earth's.

  • Women who had used HRT drugs for at least a decade were 2.5 times less likely than women who had never used them to develop Alzheimer's.

    Repeat after me: One time less equals zero. A number can't decrease more than one time or more than 100 percent. What you see in these examples is the common error of twisting a comparison inside out. If Earth's atmosphere is 100 times as dense as Mars's, Mars's atmosphere is one-one-hundredth as dense as Earth's. It's 1 percent as dense. It's 0.01 times as dense -- not even "one time less dense," let alone the nonsensical "100 times less dense."

  • Now what?


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