Week 20: Find a denominator

 Is this Beautiful heirloom crib also a CPSC non-compliant death trap? Identifying the missing denominators in scary sounding pregnancy and parenting articles can help you make better-informed decisions. |  The Metropolitan Museum of Art

Is this Beautiful heirloom crib also a CPSC non-compliant death trap? Identifying the missing denominators in scary sounding pregnancy and parenting articles can help you make better-informed decisions. | The Metropolitan Museum of Art

In case you forgot your homework assignment from last week, here’s a quick reminder. One way to combat the scary numbers you see in the news is to develop a personalized set of numbers.

It helps if you encounter your examples often, which is why so many of my examples are food-related. A three-pound jar of Jelly Belly beans is just shy of 1200 beans. Assuming I eat a few handfuls as soon as I bring the jar home, I’ve got a good gauge of what 1,000 looks like. For smaller numbers, I turn to pasta. There are about 250 pieces in a one-pound box of fusilli.

Maybe you’re still put off food this week. If you’ve been spending a lot of time on your bathroom floor lately, use that time to count your floor tiles. This will prove especially helpful if you have penny tile. If your family is going overboard with baby clothes, count the onesies hanging in your nursery. One number that’s helpful for all parents to know is 4 million, which is a rough estimate of the number of babies born in the U.S. each year. It’s also a useful estimate for the number of U.S. children of any one age.

Once you have that number set, you’re ready to tackle scary news numbers. We may not think of numbers as rhetorical. They are clear statements of fact, or, when reported incorrectly, lies or mistakes. But numbers do make an argument. They’re often employed to make us feel a certain way about an issue. Take these preeclampsia stats from ProPublica’s piece: as many as 200,000 American women a year experience preeclampsia, and “around the world, preeclampsia kills about five women every hour.”

200,000 sounds huge, because in many contexts, it is. I’d be very happy to experience a sudden windfall of $200,000. Even 200,000 pennies would make my day. 200,000 is greater than the population of Fort Lauderdale. 200,000 miles is longer than the life of most cars, and just 39,000 miles short of the distance to the moon.

The key to making news numbers sound less scary is to put them in their proper context. Think of a scary news number as the numerator of a fraction. To know how scary that number really is, you need the denominator. 200,000 looks much smaller when compared to the roughly 4 million women who give birth in the U.S. each year. (Because of pregnancies of multiples, the number of women giving birth is slightly lower than the number of babies born, but let’s round to the nearest million.) Next to 4 million, 200,000 is small: just five percent of U.S. women experience preeclampsia. That means 95 percent of women don’t.

Identifying a denominator often means the difference between panicking about unlikely dangers and relaxing through your pregnancy. But sometimes these numbers can be hard to visualize…which is why you need that personalized set of numbers.

Using my partially-eaten 3-pound jar of jelly beans, I can physically see what my risk of preeclampsia looks like. There are 1,000 beans in the jar. I remove 50 of those beans (let’s say the buttered popcorn ones, because yuck) to represent the five percent of women who will experience preeclampsia. The remaining 950 beans represent the women who will not experience it.

What’s the fate of those 50 jelly beans? The ProPublica article makes things look pretty grim. Reading that globally, five women die from preeclampsia per hour probably has you checking yourself or your partner for swelling. But consider the sheer number of women giving birth at any minute around the globe. According to one UNICEF estimate, around the world, there are 255 babies born per minute, which means there are roughly 15,300 births per hour. Because some of those births are multiples, the number of babies born is a bit higher than the number of women giving birth, so let’s round down and say that there are about 15,000 women giving birth in any one hour. If five women die from preeclampsia per hour, that comes to about 1 in 3,000 women. I would need three jars of jelly beans to represent that risk: just 1 bean in three jars.

But that 1-in-3,000 statistic is the global risk. When you read further in the ProPublica article, you’ll see that in the U.S., the risk is much different. Fifty women die from preeclampsia each year. Fifty seems like a huge number to us, but again, we need to put that number in context. That’s fifty women out of 4 million (roughly 1 in 80,000) women in the U.S. who die from preeclampsia. I would need 80 jars of jelly beans to show my risk of dying from preeclampsia.

None of this is to dismiss the importance of better prenatal care in the U.S. or around the world. ProPublica’s preeclampsia investigation, which is part of its ongoing Lost Mothers series, is a solid piece of journalism that points to an information gap about one of the most common pregnancy complications. But it’s important to separate your personal risk from the need for improved medical care more generally. We can strive for improved care without needlessly panicking women about a condition they will never personally experience.

Training yourself to spot denominators now will help you down the road, when you read about the risk of positional asphyxia on the way home from the hospital or the nursery items most likely to send your baby to the ER.