The results are remarkably consistent. In these and more than a dozen other examples, Clark again and again finds evidence of far less mobility—a much slower rate of convergence toward the society’s general population, from either above or below—than what researchers using conventional methods have concluded.
The disadvantage of Clark’s surname method is its lack of precision about the parent-child link. The name De Belcamp, for example, wasn’t common in England in Norman times, and its modern equivalents, Beauchamp and Beacham, aren’t now. Even so, according to Clark, 3,352 Brits bear those names today. He doesn’t know who is really descended from whom. This is a far cry from the directly connected information about parents’ and children’s incomes on which most other researchers today rely.
But the advantage of looking at surnames is twofold. First, it enormously increases the spans of time Clark can study—up to 900 years in some of his English examples. Second, it allows him to examine countries, like India, where the kinds of directly linked parent-and-child data other researchers use aren’t available and may not be for decades, if ever.
No doubt economists and others will debate the relative merits of Clark’s method, along with what he’s trying to measure. But the important question is whether mobility is as slow as he says—and whether it really is a “universal constant.” Those claims are well worth taking seriously, in part because his more comprehensive notion of socioeconomic status—a concept economists typically don’t try to grapple with—does seem like what really matters.
Although Clark’s story is pretty depressing, there’s at least one brighter aspect. Some time ago Alan B. Krueger, a leading labor economist at Princeton, called attention to an especially worrisome implication of the growing body of standard research on mobility: countries with wider inequality tend to have lower mobility—which undercuts the defense of wide inequality, where it’s found, on the grounds that anyone can get ahead. Krueger labeled this deeply troubling relationship “the Great Gatsby Curve,” and economists and the popular press quickly picked up on the idea.
If Clark is right, however, there is no such relationship. The point is not that countries with wider inequality have more mobility, as we used to think. But at least they don’t have less. As Clark explains, that is a statistical illusion, the result of conventional research methods focusing only on income (or wealth).
Otherwise Clark’s is indeed a discouraging story—as, inevitably, is just about any account of human existence in which heredity is the dominant factor governing our individual destinies. As he did in his earlier book, Farewell to Alms (the annoying Hemingway puns come without explanation), Clark mostly maintains a studied ambiguity about whether our “general social competence” can be traced to genetics: “By and large, social mobility has characteristics that do not rule out genetics as the dominant connection between the generations.” And elsewhere: “This is not to say that social status is determined genetically. But whatever drives it is, on the tests performed here, indistinguishable from genetic inheritance.” As the book moves on, however, it becomes ever clearer that Clark has our genes in mind.