Economics historian finds that real social mobility takes hundreds of years

... Mobility is hard to measure ... turning not just on who earns what today but on how what people earn—and what they have—relates to their parents’ income and wealth, and their grandparents’ and prior generations’ too. Economists, to their credit, are increasingly stepping up to this difficult empirical challenge. Some are tackling the politically touchy question of whether mobility is greater in America than in western-European countries. (Our traditional civic myth notwithstanding, the answer is no.) Others are investigating whether mobility in America has declined in recent years. (Contrary to President Obama’s recent statements, it apparently hasn’t.)

Gregory Clark, an economic historian at the University of California at Davis, has looked at these questions through a different lens. Clark, too, finds that mobility here is no greater than in Europe, and that U.S. mobility hasn’t declined. But he comes to a more fundamental, far more powerful conclusion. Clark argues that mobility is always the same—in all societies, and in every era. Mobility, he claims, is “a universal constant”; over time we thrive or not according to a “social law of motion,” a “social physics of intergenerational mobility.” And to make matters worse, the universal speed at which families and groups change their social position is slow—a lot slower than everyone thinks on the basis of previous research.

The implications are profound. If mobility is constant, then the ability of social institutions to affect it must be negligible. Clark points to such changes as the movement from feudalism to democracy and then the expansion of the franchise, as well as free public education and redistributive taxation. But if modern America and modern Sweden have the same rate of mobility, and that rate is the same as what prevailed in medieval England and in 19th-century China, then none of those changes mattered. And if the journey from unusually high or low status to the middle can, as Clark claims, “take ten or fifteen generations (300–450 years),” the mobility-based defense of inequality becomes strained, here and everywhere else.

Why does Clark find mobility rates to be so much slower than other economists do? To begin with, he’s measuring something different. Most economists assess intergenerational mobility by looking at what people earn, or in some cases what they own, compared with their parents’ income or wealth. Clark is after something broader, encompassing not just people’s income and wealth but also their education, their occupation, their likelihood of holding elected office or other distinguished positions, or of belonging to elite groups. He refers to the entire constellation of such attributes as “status,” or “fundamental social competence,” or “general social competence or ability”—ultimately, “an inescapable inherited substrate, looking suspiciously like social class.” Clark argues that this more comprehensive concept of mobility is what most of us really care about, and he’s probably right. The zillionaire’s son who spends all his time on philanthropy earns a lot less than his father did, but he enjoys a pretty high social standing nonetheless...