"Back in the 60s and 70s — which I, sad to say, actually remember — there was much talk about the disintegration of the black family and of African-American values more generally, and how that was the root cause of America’s poverty problem. And the social dysfunction was clearly real. But was it cause or effect? William Julius Wilson, in When Work Disappears, famously argued that it was a symptom: good jobs in inner cities, where African-American men could take them, went away, and the cultural changes followed.
So, how could you test that hypothesis? Well, here’s an experiment: change the structure of the economy in such a way that a large class of white men — say, white men without a college degree — similarly lose access to good jobs. If Wilson was right, we’d expect to see a sharp decline in stable marriages, a rise in unwed births, growing drug use, and other forms of social disruption.
And that is, in fact, exactly what happened: William Julius Wilson was right. Which makes it remarkable to see people look at that very evidence and say that it shows that the real problem isn’t money, it’s values."
I encourage you to read Krugman's excellent blog. I'll be seeing him talk at SXSW too...