Low mobility associated with inherited ability is no social tragedy

By Gregory Clark | University of California, Davis

This week's Free exchange column discusses new research on rates of inter-generational social mobility (summary here). We are inviting experts in the field to comment on the piece and related research. Miles Corak, an economist at the University of Ottawa, responded here. Francisco Ferreira, lead economist at the World Bank's Development Research Group, responded here. Next up is Gregory Clark, an economist at the University of California, Davis.

I WANT to make two points in the discussion of social mobility.

(1) Studies of social mobility using surnames suggest two things. Social mobility rates are much lower than conventionally estimated. And social mobility rates estimated in this way vary little across societies and time periods. Sweden is no more mobile than contemporary England and the USA, or even than medieval England. Social mobility rates seem to be independent of social institutions (see the other studies on China, India, Japan and the USA now linked here).

Francisco Ferreira rejects this interpretation, and restates the idea that there is a strong link between social mobility rates and inequality in his interesting post.

What is wrong with the data Ferreira cites? Conventional estimates of social mobility, which look at just single aspects of social status such as income, are contaminated by noise. If we measure mobility on one aspect of status such as income, it will seem rapid.

But this is because income is a very noisy measure of the underlying status of families. The status of families is a combination of their education, occupation, income, wealth, health, and residence. They will often trade off income for some other aspect of status such as occupation. A child can be as socially successful as a low paid philosophy professor as a high paid car salesman. Thus if we measure just one aspect of status such as income we are going to confuse the random fluctuations of income across generations, influenced by such things as career choices between business and philosophy, with true generalised social mobility.

If these estimates of social mobility were anywhere near correct as indicating true underlying rates of social mobility, then we would not find that the aristocrats of 1700 in Sweden are still overrepresented in all elite occupations of Sweden. Further, the more equal is income in a society, the less signal will income give of the true social status of families. In a society such as Sweden, where the difference in income between bus drivers and philosophy professors is modest, income tells us little about the social status of families. It is contaminated much more by random noise. Thus it will appear if we measure social status just by income that mobility is much greater in Sweden than in the USA, because in the USA income is a much better indicator of the true overall status of families.

(2) Many commentators automatically assume that low intergenerational mobility rates represent a social tragedy. I do not understand this reflexive wailing and beating of breasts in response to the finding of slow mobility rates. The fact that the social competence of children is highly predictable once we know the status of their parents, grandparents and great-grandparents is not a threat to the American Way of Life and the ideals of the open society.

The children of earlier elites will not succeed because they are born with a silver spoon in their mouth, and an automatic ticket to the Ivy League. They will succeed because they have inherited the talent, energy, drive, and resilience to overcome the many obstacles they will face in life. Life is still a struggle for all who hope to have economic and social success. It is just that we can predict who will be likely to possess the necessary characteristics from their ancestry.