Gene Expression

Religiosity and teen birth rate in the United States:

Increased religiosity in residents of states in the U.S. strongly predicted a higher teen birth rate, with r = 0.73 (p<0.0005). Religiosity correlated negatively with median household income, with r = -0.66, and income correlated negatively with teen birth rate, with r = -0.63. But the correlation between religiosity and teen birth rate remained highly significant when income was controlled for via partial correlation: the partial correlation between religiosity and teen birth rate, controlling for income, was 0.53 (p<0.0005). Abortion rate correlated negatively with religiosity, with r=-0.45, p=0.002. However, the partial correlation between teen birth rate and religiosity remained high and significant when controlling for abortion rate (partial correlation=0.68, p<0.0005) and when controlling for both abortion rate and income (partial correlation=0.54, p=0.001).

They used data from the Religious Landscape Survey to create an index of religiosity from the following variables:

1) Belief in a God or universal spirit: Absolutely Certain.
2) There is only one way to interpret the teachings of my religion.
3) Scripture should be taken literally, word for word.
4) How important is religion in your life: Very Important.
5) My religion is the one true faith leading to eternal life.
6) Frequency of attendance at religious services: at least once a week.
7) Frequency of prayer: at least once a day.
8) How often do you receive a definite answer to a specific prayer request: at
least once a month.

Here's the scatterplot from the paper:

There are two immediate issues which jump out:

1) They needed to control for race. Black Americans are considerably more religiously conservative than white Americans and have higher teen birth rates. Additionally, black Americans are a higher proportion in states where the whites are also religiously conservative (e.g., Mississippi). Perhaps later I'll crunch the data and see what effect that has (though I am rather confident that there will still be some state-level relationship).

2) Looking at this question on the state level probably inverts the direction of the relationship between religiosity and teen births, all variables controlled, when you look at the whole population of the United States. I say this based on the introduction of the paper where they review the literature from the National Longitudinal Survey of Youth which seems to be much fuzzier than the relationship that they're finding here, and more often than not suggest that religiosity mitigates against the behavior which leads to teen birth.

Remember Andrew Gelman's work in Red State, Blue State, Rich State, Poor State: Why Americans Vote the Way They Do; in many "rich" blue states the rich actually vote red. Similarly, there are plenty of data to suggest that in many secular nations more religious individuals are happier and less neurotic, but very religious nations just end up sucking. The relationship is robust enough that I think one might wonder if there's a hydraulic analogy which might be useful; all things equal religion might encourage good behavior, but in societies which don't suck too much it is impossible to maintain high levels of religiosity.