Wednesday, August 23, 2006

The Fertility Gap

According to one Arthur Brooks, we liberals are going extinct because the conservatives are outbreeding us. The same Arthur Brooks has also argued that far lefties are more hateful than far righties, whatever these terms might mean, and that conservative young people are more compassionate than liberal young people. This is one busy professor, isn't he?

What is interesting about all these opinion pieces is what happens when you try to find the study he is quoting. Because there is no study available at all anywhere online or listed on the Professor's homepage. Perhaps Professor Brooks does calculations on the back of a pack of Marlboros or more likely his prayer book? Wherever these calculations might be, they are not available for the scrutiny of others. Instead, we are steered to the raw data he presumably has used. Go on, he dares us, go and make up your own studies. I'm not telling you what variables I picked and how I standardized for them.

This makes discussing the fertility gap a little bit iffy, largely because I have no way of checking Professor Brooks's arguments. To be quite honest, I find the unavailability of the supposed evidence unethical, unless I just didn't look hard enough.

But let's see what Brooks says:

But the data on young Americans tell a different story. Simply put, liberals have a big baby problem: They're not having enough of them, they haven't for a long time, and their pool of potential new voters is suffering as a result. According to the 2004 General Social Survey, if you picked 100 unrelated politically liberal adults at random, you would find that they had, between them, 147 children. If you picked 100 conservatives, you would find 208 kids. That's a "fertility gap" of 41%. Given that about 80% of people with an identifiable party preference grow up to vote the same way as their parents, this gap translates into lots more little Republicans than little Democrats to vote in future elections. Over the past 30 years this gap has not been below 20%--explaining, to a large extent, the current ineffectiveness of liberal youth voter campaigns today.

Alarmingly for the Democrats, the gap is widening at a bit more than half a percentage point per year, meaning that today's problem is nothing compared to what the future will most likely hold. Consider future presidential elections in a swing state (like Ohio), and assume that the current patterns in fertility continue. A state that was split 50-50 between left and right in 2004 will tilt right by 2012, 54% to 46%. By 2020, it will be certifiably right-wing, 59% to 41%. A state that is currently 55-45 in favor of liberals (like California) will be 54-46 in favor of conservatives by 2020--and all for no other reason than babies.

The fertility gap doesn't budge when we correct for factors like age, income, education, sex, race--or even religion. Indeed, if a conservative and a liberal are identical in all these ways, the liberal will still be 19 percentage points more likely to be childless than the conservative. Some believe the gap reflects an authentic cultural difference between left and right in America today. As one liberal columnist in a major paper graphically put it, "Maybe the scales are tipping to the neoconservative, homogenous right in our culture simply because they tend not to give much of a damn for the ramifications of wanton breeding and environmental destruction and pious sanctimony, whereas those on the left actually seem to give a whit for the health of the planet and the dire effects of overpopulation." It would appear liberals have been quite successful controlling overpopulation--in the Democratic Party.

Note that to say that "the fertility gap doesn't budge when we correct for factors..." is wrong. The gap just budged, didn't it? It went from 41% to 19%. Or so Brooks tells us. And note that factors such as age really should be standardized, because young adults have not yet completed their families. In other words, the initial 41% gap is not the gap we would be interested in, always assuming that this is the starting value for the gap.

Brooks doesn't say anything about the dreaded Latino immigration, the one that Buchanan ranted about so very recently. These immigrants have lots of children, you know, and they are more likely to be Democrats than Republicans. But then opinion pieces don't have to explain everything carefully. Statistical evidence, however, should not be a matter of opinion.