Land of opportunity

The Wall Street Journal's editorial writers are impressed by a new study on income mobility:

The Treasury study examined a huge sample of 96,700 income tax returns from 1996 and 2005 for Americans over the age of 25. The study tracks what happened to these tax filers over this 10-year period. One of the notable, and reassuring, findings is that nearly 58% of filers who were in the poorest income group in 1996 had moved into a higher income category by 2005. Nearly 25% jumped into the middle or upper-middle income groups, and 5.3% made it all the way to the highest quintile.

Of those in the second lowest income quintile, nearly 50% moved into the middle quintile or higher, and only 17% moved down. This is a stunning show of upward mobility, meaning that more than half of all lower-income Americans in 1996 had moved up the income scale in only 10 years.

I would call this a case of being prematurely stunned. Studies of this kind always and everywhere show people rising out of lower quintiles and dropping out of higher ones: this pattern merely reflects the ebb and flow of income during the course of a typical career. Students or the unemployed in the lowest quintile subsequently get jobs; the highest-earners subsequently retire. By themselves these numbers tell you very little about the life-chances of people who are born poor compared with the life-chances of people who are born rich (mobilty) or for that matter about the gap between rich and poor (inequality).

Changes over time in the ratios tell you more. The WSJ notes that the study finds no great change in relative income mobility over the past ten years. But, concentrating on mobility, international comparisons are what you need to test the view that the United States really is the land of opportunity, as compared with other places. What do those comparisons say? Thank you for asking:

Most researchers now give America much lower marks than they used to for intergenerational economic mobility—the ease with which successive generations move up or down relative to their parents. As flaws in early postwar studies have been addressed, estimates of mobility have fallen. Before the 1990s, researchers tended to put the correlation between parents’ incomes and their children’s at around 20 percent, implying a high degree of mobility between generations. (Zero would imply no connection at all; a correlation of 100 percent would imply that parents’ incomes entirely determined the incomes of their children.) In the 1990s, using better data and techniques, experts tended to put that figure at about 40 percent. Recent estimates run as high as 60 percent. The finding is not that mobility has fallen since World War II—the studies point to no clear trend. It is that as methods of measuring mobility have improved, the result, across a span of recent decades, has gotten worse. The earlier view that postwar America was an economically mobile society is less and less borne out. Perhaps it was once (before data became available to track such things accurately); but it isn’t now.

More telling, maybe, is the international comparison. America stands lower in the ranking of income mobility than most of the countries whose data allow the comparison, scoring worse than Canada, all of the Scandinavian countries, and possibly even Germany and Britain (the data are imperfect, and different studies give slightly different results).

Strikingly, the research suggests that mobility within America’s middle-income bands is similar to that in many other countries. The stickiness is at the top and the bottom. According to one much-cited study, for instance, more than 40 percent of American boys born into the poorest fifth of the population stay there; the figure for Britain is 30 percent, for Denmark just 25 percent. In America, more than in other advanced economies, poor children stay poor. Other data show that in America, more than in, say, Britain, rich children stay rich as well.

You can read the rest of my recent Atlantic Monthly column on the subject here (subscription required).