Friday, September 30, 2005

Bennett, Levitt, the Numbers

Philosopher-talkmaster Bill Bennett has posed a question that has proven to be too hard to understand for the likes of Alan Colmes and the Lost Kos Krowd:

CALLER: I noticed the national media, you know, they talk a lot about the loss of revenue, or the inability of the government to fund Social Security, and I was curious, and I've read articles in recent months here, that the abortions that have happened since Roe v. Wade, the lost revenue from the people who have been aborted in the last 30-something years, could fund Social Security as we know it today. And the media just doesn't -- never touches this at all.

[snip some minor exchanges]

BENNETT: All right, well, I mean, I just don't know. I would not argue for the pro-life position based on this, because you don't know. I mean, it cuts both -- you know, one of the arguments in this book Freakonomics that they make is that the declining crime rate, you know, they deal with this hypothesis, that one of the reasons crime is down is that abortion is up. Well --

CALLER: Well, I don't think that statistic is accurate.

BENNETT: Well, I don't think it is either, I don't think it is either, because first of all, there is just too much that you don't know. But I do know that it's true that if you wanted to reduce crime, you could -- if that were your sole purpose, you could abort every black baby in this country, and your crime rate would go down. That would be an impossible, ridiculous, and morally reprehensible thing to do, but your crime rate would go down. So these far-out, these far-reaching, extensive extrapolations are, I think, tricky.

The point is entirely one of arithmetic. To illustrate, if a community were made up of four equal and identifiable groups which we can call A, B, C, and D. And their crimes rates, per thousand citizens were: A; 8, B;6, C;4, D;2, the community would have a crime rate of 5 per thousand (20/4=5).

Were the community to forcibly abort all babies in the A group, that group would eventually disappear from the community. Leaving a three group community with crimes rates B;6, C;4, D;2, averaging only 4 crimes per thousand (12/3=4).

Bennett's point, and you don't need a John Bates Clark medal to understand it, being that if you eliminate a high crime rate group (and black Americans have about the highest rate of violent crime) from a community, you must--by the laws of grade school arithmetic--reduce the average crime rate for the community.

Not rocket science.

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