A Little Math Lesson for Newsies

Last month. Prof. Emerson Hoogstraat shared a little math lesson for newsies. Unfortunately, his treatise barely tapped the subject's surface. As other readers repeatedly point out, our transgressions go way beyond the few examples he so diplomatically cited. Among them:

• Numbers that just don't add up:
  1. Deck: The Pentagon proposal would cut nearly 200 ships....
     Lead: The Navy has proposed slashing its current 452-vessel fleet to 340 ships....
     Take 340 away from 452 and you get 112, which is a long way from "nearly 200." Besides, a vessel can include anything from a captain's gig to a battleship. Theoretically, you could slash a 452-vessel fleet to 340 ships without eliminating a single vessel that actually qualified as a ship.
     
     
  2. The Oregon Comprehensive Firearms Act went into effect in 1990.... In 1989 there were 11,743 concealed weapons permits in Oregon. In the first year of the law, the number of permits went from a few hundred to 13,240. Through December 1993, the number had shot up to 40,040. During January 1994, 1,192 more were issued.
     Hmmmmm.... 11,743 in '89. A few hundred at the beginning of '90. More than 13,000 by the end of '90. A grand total for the last month of '93, but a monthly total for the first month of '94. What is going on here?
     
     
  3. Last week, Tri-Met's board of directors adopted a plan that calls on the agency to add 125,000 new riders a day by 1998. It would be a big jump.
     It certainly would be. As William Burr, one of our more faithful correspondents, points out, 125,000 riders a day from the date of publication until the beginning of 1998 totals 216,375,000 new riders.
     
     
  4. Oregon farmers plant about 25,000 acres of Blue Lake bush beans each year, harvesting 2.5 times the yield of Wisconsin, which leads the nation in bean production.
     Well, maybe the writer meant that Wisconsin was harvesting lots of other kinds of beans. But she still managed to confuse at least one readers, who wrote to find out what was going on.
  5. Rail statistic: "Each year, 3 million to 4 million American women are battered by their husbands or boyfriends, making battery the most significant cause of injury." -- U.S. Surgeon General.
     Text statistic: According to the National Coalition Against Domestic Violence ... more than half of women are battered some time in their lives; more than one-third are battered repeatedly every year....
     So which should we believe. On first thought, the government source seems likely to be more responsible than the advocate. A second thought should clinch the decision: If what the NCADV says is true, something like 100 million American women are battered every year. Let's hope they all plan to ride Tri-Met.

  6. Not only do these numbers not add up, they don't even make sense.

     According to the Job Corps, which tracks former students for six months, 67 percent of the graduates get jobs and 17 percent go on to higher education. Those percentages include the nearly four in 10 students who quit the program in the first three months or are kicked out for infractions like using drugs or carrying a weapon.
     Not only do these numbers not add up, they don't even make sense. How can figures for graduates include figures for students kicked out in the first three months?
     
     
• Mangled survey terms or results:
  1. ... the study's results are accurate within 3 percentage points.
     Nobody can make such a claim. The researchers probably reported that the study's margin of error was 3 percentage points. That means there is a known likelihood (usually 95 out of 100) that the true results are with 3 percentage points -- plus or minus -- of the results actually obtained.
  2. However, Wolraich said these three differences, while statistically significant, could still have occurred as a matter of chance.
     Of course they could have occurred by chance! Any result based on sampling can occur by chance. At the 95 percent level of confidence, 5 out of every 100 findings will occur by chance.
  3. Random samplings of audiences at a dozen or so of his speeches in four states over the past two months indicates that most are made up of longtime supporters.
     A "random sampling" is a strictly scientific sample. Survey researchers spend huge amounts of money trying to approximate random samplings.
     The writer who produced this example meant what the researchers call an "accidental sample." The most graceful way to say that for a general audience is "a casual sample," as in "a casual sampling of audiences."
     
     
• Mislabeled statistics:
  1. To evaluate this level of debt, consider that for a corporation, a debt-to-equity ratio of 40 percent is considered pretty good.
     A ratio and a percentage are not the same thing. Percentages are all built from a base of 100. Ratios are simply comparisons of two numbers. "The ratio of potatoes to onions was 2-1."
     In this case, the writer presumably meant debt equal to 40 percent of total equity. In that case, the equity-debt ratio would be 60-40, or 3-2.
     
     
• Numbers without context:
  1. It appears to me, assuming that reporting patterns have stayed the same ... certainly we are more safe today than we have been in the past in Oregon," said Willhite, 47, who has been forecasting state prison-bed needs or analyzing crime data since 1987. "So we are doing a better job somehow."
     Oregon's crime rate may be down, but the conclusion that the authorities are therefore doing a better job is nonsense. For one thing, young men commit the vast majority of crime. So the most important statistic when it comes to the level of crime is the percent of the population that consists of men from 18 to 35. Crime rates go down when an especially large cohort of men passes through that age range and into their mellower middle years. That's what's happening now that the last of the Baby Boomers are into their 30s. So the crime rate could well be falling even if the authorities are doing a much worse job.
     Besides, as Willhite himself pointed out in the same story, the Oregon's population growth includes an influx of well-educated professionals. They don't commit much crime (at least the kind that shows up in FBI statistics), and that factor alone could reduce the crime rate.
     
     
• Incomplete statistics:
  
  1. We ran a cancer-scare story from the New York Times with this lead: Women who do not smoke but are married to men who do have a small but increased risk of developing lung cancer, a study has confirmed.
     We could have chosen from four additional wire stories on the same subject. Several key numbers failed to match:
     -- AP: The study found that the risk of developing lung cancer for the women with spouses who smoke was about 30 percent higher over a lifetime than for those with nonsmoking spouses."
     -- L.A. Times: "In the largest and most comprehensive study of its kind, researchers in four states reported Tuesday that long-term exposure to secondhand cigarette smoke can increase the risk of lung cancer in non-smoking women by as much as 86 percent....
     -- Newsday: The EPA report consolidating data from 30 studies worldwide and concluded that a woman who lives with a smoker is 1.19 times as likely to develop lung cancer as a woman living with a non-smoker. In the Fontham-led study the comparable figure is 1.29.
     The confusion over the numbers is interesting enough. But what's even more flabbergasting is the fact that the key number is totally missing from all the stories.

     We often leave the critical number out of disease-risk stories. What readers need to know is not their relative risk, but their actual risk. Let's give it to them.

     
     If you were a women who lives with a smoker, the only number relevant to whether you leave or stay is your ACTUAL chance of developing lung cancer, not your chance relative to someone living with a non-smoker. If the chance is one in a thousand, what difference does a difference of 19 percent, 29 percent, 30 percent or 86 percent actually make. At worst, hanging around the same old house increases your odds of getting lung cancer to something less than two in a thousand.
     We often leave the critical number out of disease-risk stories. What readers need to know is not their relative risk, but their actual risk. Let's give it to them.
     
     
  2. Sales average $1,113 per machine -- and that's a lot of tickets.
     Sales average $1,113 over what period of time? The number is nearly meaningless without that context.
     
     
• Conclusions that go way beyond the numbers:
  1. Headline: At lunchtime, it never fails: Men network, women run errands.
     Text: Researchers at the University of California, Irvine, found that 51 percent of women said they shopped or ran errands at lunch. Only 39 percent of men claimed to do the same.
     Nothing in the text supports the conclusion in the headline. Nobody asked men what they were doing instead of errands. The percentage of women who report running errands hardly justifies the claim that "it never fails."
     
     
• Numbers that don't match:
  1. Although estimates vary, taxol costs about $22,000 an ounce. It takes 9,000 pounds of dry bark to produce a pound of taxol.
     We regularly ask our readers to do the math instead of doing it ourselves. When we cite numbers, let's make them easily comparable. If taxol is $22,000 an ounce, we don't care how much bark it takes to make a pound. We care how much it takes to make an ounce.
     There are 16 ounces in a pound. Ergo, it takes a little over 560 pounds of bark to make an ounce. Or, to run at it from a different direction, 9,000 pounds of bark will produce a pound of taxol worth $352,000.
  2. Each gallon of the chemical produces 5.4 kilograms, or 12 pounds, of heroin, Van Horn said. The drug is commonly sold wholesale by the "piece," which is 25 grams and typically sells for about $2,500. Each gram of heroin makes 20 user doses that sell on the street for $20 each, Van Horn said. At $20 per dose, a "piece" of heroin would make 500 users doses and sell for a total of $10,000 retail, and a kilogram would be worth $400,000.
     So how much is a pound worth?

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