A silly question, isn’t it? How do you decide what to print, what to cut, how to summarize without understanding what the numbers mean? In the late 1980s John Allen Paulos published Innumeracy (brief review here) to warn about the degradation of mathematical knowledge. A couple of decades on it could be worse.
The nearby, slightly oversized image is a screen shot of a portion of The Atlantic’s home page. Obviously meant to grab our attention, the teaser text claims that in light of the New York State gay marriage deal the number of Americans who are now eligible to wed has doubled. For unintended reasons that got me to click further. Turning inside, the reality is a little bit different, okay, a lot bit different from, that teaser. Here is the portion of the article that the teaser must refer to:
How many more Americans are now eligible to marry?
• With the passage of the New York State Marriage Equality Act, the percentage of the U.S. population living in a state that allows same-sex couples to marry has more than doubled, from 5.1 percent to 11.4 percent according to the 2010 Census. Similarly, the percentage of same-sex couples living in states that allow them to marry has doubled from 6.9 percent to 14.3 percent.
That’s a different statement than the teaser for two reasons. The first is simple logic. In states that do not recognize gay marriage neither men nor women are barred from marriage, just from same-sex marriage. I know that sounds like splitting hairs but children 14 and under are probably barred from marriage in all 50 states. What it means is that the definition of the whole should be specified.
Let’s use those kids to show the math problem. The Census Bureau says the proportion of children 14 and under in the population is right around 20%. Let’s say that the homosexual population is 10% of the whole. (I don’t want to enter into a debate. It’s an illustrative figure, not a fact.) Remove the kids who may not have figured out their sexuality yet and you have between 8% and 10% of the population. But the population is not distributed evenly by age or by sexual preference.
The addition of New York to the list of states recognizing same-sex marriage adds about 19 million people to the total population of states doing so. That does not mean that all 19 million are suddenly allowed to marry. We should probably take out at least the 20% we think are 14 or under. Unless the remaining 15 million people or so are gay, they are not suddenly eligible for marriage under the new law. Probably the majority of them already could wed.
Let’s say the population of New York that is homosexual and over 14 is 20%. We added 3 million people to the population that can legally marry. A significant leap to be sure, but not a doubling of “Americans now eligible to wed..”
At least not by the numbers.