Gregory Clark's startling new book, "The Son Also Rises," asks you to rethink everything you thought you knew about social mobility. His research, if it's correct, isn't good news. It says that socioeconomic status is mostly a matter of nature not nurture, and suggests that trying to help the disadvantaged move up won't make much difference.
These findings defy the prevailing consensus, and one wants them to be wrong. But what if they're not?
Clark, a professor of economics at the University of California, Davis, proposes a new way to measure mobility across nations and over time. He tracks the persistence of rare surnames at different points on the socioeconomic scale.
Samuel Pepys, the diarist, was a top civil servant and member of Parliament in 17th century England. An earlier Pepys first surfaced as a high-status Englishman in 1496, when he enrolled at Cambridge University. There were never more than a handful of Pepyses - as few as 18 by 2002 - but for more than 500 years, people with that surname have been consistently successful.
Since 1496, at least 58 Pepyses have enrolled at Oxford or Cambridge, most recently in 1995. For an average surname of this population size, the expected number of enrollees would be two or three. Of the 18 Pepyses alive in 2012, four are medical doctors. The nine who died between 2000 and 2012 have left estates with an average value of 416,000 pounds, more than five times the average estate value in England in this period.
Consensus estimates of social mobility find that a person's status (measured by income, wealth, occupation or in other ways) is only moderately correlated with that of his or her parents. The usual numbers would make the history of the Pepyses very unusual. But the history of that particular rare surname turns out not to be a fluke or exception. Clark and his collaborators have dug deeply through decades and centuries of data connected with rare surnames - for rich people, poor people and those in between; not just in England, but for the U.S. and many other countries, too.
The same pattern emerges: Social status is amazingly persistent. There's some regression to the mean - names at the top move down and names at the bottom move up - but it's an agonizingly slow drift.
Even more remarkably, this persistence of status hardly varies from country to country, or period to period. This finding too defies the consensus - and, many would say, common sense.
Social mobility isn't any higher in Sweden, say, than in the United States - or, for that matter, any higher in modern England than in medieval England. The surname evidence asks us to believe that cultural and environmental differences don't much matter, that the advent of universal education and the modern welfare state, political upheavals, revolutions and world wars, made little difference. Through it all, social status was inherited as strongly as though it were a biological trait, like height.
The Economist's reviewer wrote: "'The Son Also Rises' may not be a racist book, but it certainly traffics in genetic determinism." As a rule, one traffics in things like illegal drugs and pornography, not in scientific findings. Genetic determinism is a horrible thing to contemplate, and it's a theory one wants to be false. Unfortunately, that doesn't make it false.
Clark's results are hard to dismiss because he offers a plausible theory of why they differ from those of other researchers. Socioeconomic status is a bundle of characteristics: income, wealth, education, profession, type of residence and so on. These individual measures are noisy. The son of a rich family may choose to work as a poor academic - downward mobility in income. The daughter of well-educated parents may drop out of college to start a software company - downward mobility in education.
Underlying social status, the whole bundle, is much less variable, and that's what gets passed along to the next generation. So the individual measures that formed the consensus have systematically understated the real persistence of social status.
If Clark's findings are correct, it doesn't mean that efforts to help the poor are pointless. On the contrary, he argues, the findings strengthen the case for redistribution. (In a world of low social mobility, the costs of redistribution are lower and the need greater.) It doesn't follow, either, that efforts to improve mobility will have no effect at all - only that they will have, at best, much less of an effect than one would wish.
This doesn't seem good enough. Impressed as I am by this fascinating book, I'd love Clark to be proved wrong. And he must be wrong, mustn't he? Mobility in modern welfare-state societies is no higher than in pre-modern times? Please. Yet that's what his data - ingeniously gathered and carefully analyzed - seem to show.
Don't tell me he's a closet racist to say these things. Tell me where his analysis went wrong.
Clive Crook is a member of the Bloomberg View editorial board.