Friday, October 12, 2007

Pathetic Statistics

One of the top-of-the-fold articles at Fox News describes the latest release of worldwide abortion statistics as recently published in The Lancet. Currently, the headline reads "1 in 5 Pregnancies Ends in Abortion", which, while tragic, is at least believable. The sub-headline, however, is an absolute shock: "New study finds that 90 percent of women worldwide will have an abortion during childbearing years, based on 2003 data."

Now, my jaw hit the floor on this one. Fortunately, the very first paragraph of the article reads:
The study also found that, on average, 90 percent of women worldwide will have an abortion before the age of 45, based on 2003 data. However, many women will have had multiple abortions and many none at all to come to this average.

In other words, journalists are retarded.

Ignoring the incredibly poor wording of the above paragraph, the statement itself is completely absurd from a statistical standpoint. Based on the last sentence, here's what I assume they (the journalists, rather than the folks who wrote the article, I hope -- although The Lancet seems prone to publishing complete and utter garbage when it comes to "public health statistics" -- e.g., the Iraq War casualty studies indicating over 600,000 "excess deaths", etc. -- and if you want to argue with me over those numbers, ask me about death certificates) did to arrive at that "statistic": they took the number of expected abortions over the lifetime of all women up to their 45th birthday, and used this number to divide the number of women who could, presumably, have abortions, thus yielding this absurd "number of women per abortion" "statistic." Let's assume that all women, from age 10 to age 45, could become pregnant and have an abortion. A quick check at the UN world population database (what? The UN, actually good for something? You didn't hear that from me!), and some quick number crunching of that data, indicates that, in 2005, there were just shy of 1.8 billion women in that age bracket. If my assumption is correct, this ratio would come out to be 0.9, and thus, "90 percent of women will have an abortion". By implication, then, the expected number of abortions comes out to be approximately 1.8 billion / 0.9, or 2 billion abortions.

This, like I said above, is just plain stupid, and shows an impressive amount of innumeracy on the part of both journalists and their editors who let this junk get posted on the front page of Fox News. A reasonable statistic that actually contains information would be the inverse of the above statistics, which would tell is precisely, "on average", how many abortions any particular woman might have. While still a bit misleading, saying that "on average, a woman will have 1.1 abortions in her life" would at least be a true statement (based on my assumptions), in a statistical sense. While I could go off on a rant about why the number they present is not, in any sense, "on average", I won't, because I don't feel like typing out the math, and as far as I know, there's no native support for Latex equation display on Blogger (and I'm too lazy to double-check this). But let me illustrate it with a simple extension. Suppose it was expected that, instead of 2 billion abortions, only 1.5 billion abortions would be performed over the life of all women before the age of 45. There is nothing, physically or mathematically, to prevent this result. Then, Fox's startling statistic would have to read: "New study finds that 120 percent of women worldwide will have an abortion during childbearing years!!!!!!"

No sane person would draw that conclusion: like I said, such a statistic is utterly meaningless, and presumably generated purely for shock value. This is a simple reductio ad absurdam, in which an impossible result is generated using an underlying premise, thereby proving the premise to be incorrect.

What does all this mean? Well, at the very least, that I get outraged as much by junk mathematics as I do by abortion. And if you know my feelings about abortion, that's saying a lot. It also proves that, as I said about, journalists (or, possibly, Lancet "scholars", but to be fair, I expect this is not their fault) are imbeciles. Finally, it, and the whole study, which shows abortion numbers decreasing both in raw value and as a percentage of population, proves that we who care about the sanctity of innocent human life have a long way to go, but at least we're on the right track.

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Anonymous Marty said...

It's "reductio ad absurdum".

Reporters are one of the reasons why politicians never say anything that carries any meaning other than the platitudinous.

8:45 AM  
Blogger Benjamin said...

Don't you have your own blog to grammar-nazify? A simple typo, I swear!

Just more evidence that "journalism" degrees should be required to be BS degrees (no pun intended) and not BAs.

8:54 AM  

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