Robert Samuelson is happy to tell us that contrary to what he hoped some of us believed, there was not much change in mobility for children entering the labor force between the first President Bush and second President Bush's administrations. Samuelson misrepresents the study to imply that it finds that there has been no change in mobility over the post-war period.
"By the conventional wisdom, American society is becoming more rigid. People’s place on the economic ladder (“relative mobility”) is increasingly fixed.
"Untrue, concludes the NBER study."
Samuelson then notes the study's finding that there has been little change in mobility for workers entering the labor market in 2007 compared to 1990. The study then refers to earlier work finding no change in mobility prior to 1990. This study did not itself examine the period prior to 1990.
This is important since that is the period in which we might have expected growing inequality to have a notable impact on mobility. There was some divergence between quintiles of income distribution in the 1980s. In the years since 1980, there has not been much divergence between the bottom half of the top quintile and the rest of the income distribution. Most of the inequality was associated with the pulling away of the one percent from everyone else. This study made no effort to examine mobility into the one percent.
As far as mobility in the years prior to the 1990, contrary to the claim of this study, the research is far from conclusive. For example, an assessment published by the Cleveland Fed concluded:
"After staying relatively stable for several decades, intergenerational mobility appears to have declined sharply at some point between 1980 and 1990, a period in which both income inequality and the economic returns to education rose sharply. This finding is also consistent with theoretical models of intergenerational mobility that emphasize the role of human capital formation. There is fairly consistent evidence that intergenerational mobility has stayed roughly constant since 1990 but remains below the rates of mobility experienced from 1950 to 1980."
While it would be wrong to take this statement as conclusive, it is also wrong to take the assessment of the study cited by Samuelson as conclusive and it is a gross misrepresentation to imply that this study examined patterns in mobility over the whole post-war period. It did not even try to examine changes in mobility over the 1980s, the period when patterns in inequality would have most likely led to a decline in mobility.
Note: Link fixed, thanks Dennis.