The Associated Press has a story across the country today by Stephen Ohlemacher with headlines like "Income Gap Between Families Grows." They are reporting on a series of studies by Julia Isaacs of the Brookings Institution on economic mobility. The news hook is that the black/white gap in family income is growing. The scariest finding is that nearly half of black children who grew up in middle class homes have moved down economically compared to the family they grew up in.
The main explanation extracted from the Isaacs studies is that black men's real earnings, on average, declined since the late 1960s, whereas white men's average earnings went up.
When we look inside the report, though, I think the more striking and more explanatory fact is what happened to black married families. In 1969, most black families (58%) were married-with-kids families. By 1998 that had fallen to a mere third. Single-with-kids families, meanwhile, had risen from a fifth of all black families to nearly a third (29%). It is reasonable to assume that most black children in the top two quintiles in 1969 were in married-parent homes. By 1998, as Isaacs notes, most American families needed two incomes to be middle class. Black marriages, and the income advantages that come with them, were declining at exactly the time when they were most needed for the kids to match the middle class lives of their parents.
I think the decline in black men's income is also an effect of the marriage decline. Men work the hardest and the most when they are married fathers. In 1969, two thirds of black men were married; today not even half of black men are married.
To be sure, the white married-with-kids rate has fallen, too. But most white families are still married-with-kids families, and two thirds of white men are still married.
I think the main cause of the black/white gap in income and mobility is the marriage gap.