I then conducted an experiment of sorts to determine what the Soup Cans in Six Numbers model would have produced for the birth cohorts I examined using the National Longitudinal Surveys. What if, instead of using the real-world survey data, I had relied only on published estimates describing average incomes for all families and the dispersion of incomes around those averages, and had assumed a specific correlation between parent and child incomes? Following the same approach used to produce the Obama figures, I found upward mobility to have fallen from 48 to 44 percent between the early 1960s and early 1980s cohorts, rather than rising from 51 percent to 57 percent, as the real-world data indicate it did.
While the president is wrong that mobility was lower for children born in 1980 than for those born previously, it remains possible that mobility for children born today will be lower. But my experiment suggests that there is little reason to think that the Soup Cans in Six Numbers model answers that question reliably. On top of all the model’s other assumptions, estimating mobility for today’s newborns requires projecting 30 years into the future the aggregate family-income statistics that are needed to describe the joint distribution of incomes.
It would be one thing if we had solid evidence that it was a lot harder to get ahead today than in the past. But in the absence of such evidence, all the president is doing is reinforcing any doubt among the poor that they can make it if they try. In the context of a molasses-slow recovery, unsupported claims of diminished opportunities also add to the forces sapping consumer confidence. The president should stick to arguing that regardless of its trajectory, upward mobility could and should be greater than it is.
Here is my preferred statistic: A poor child has less than a one-in-five chance of ending up in the top two-fifths as an adult. That’s where most readers of this essay are or will end up — would you take those odds for your own child? We have an upward-mobility problem — one that is worse than in other countries. But it is no worse than it has ever been and it does not translate into a general lack of opportunity for the middle class. That may seem like splitting hairs, but it is not. America has challenges, but diminished opportunity is not one of them.
— Scott Winship is a fellow at the Brookings Institution and was formerly the research manager of the Pew Economic Mobility Project.