Religion and Income

Kevin Drum looks at some Andrew Gellman charts and concludes that while richer states are less religious than poorer ones, "Interestingly, there appears to be no correlation between income and religiosity within states."

But that's not really what this second chart says. Rather, as Gellman puts it "overall we see a positive correlation between income and religiosity in poor states and a negative correlation in rich states." Basically, if you live in a poor state, then the richer you are the more likely you are to go to church, whereas if you live in a rich state it's the reverse. I wonder to what extent that finding might just reflect a U-shaped distribution of church attendance with people in the middle more likely to be observant than those at either extreme. I also wonder how this would look if we used educational attainment instead of income.