The conclusions of a recent study by Neil cummins and a colleague suggests that social mobility in modern England is somewhat greater than in pre-industrial times. Using surnames, they show that the intergenerational correlation of status is close to 0.85, which means that the offspring of the rich and the poor will take more than 20 generations, or 600 years, to converge towards the mean of the company. This indicates that there are very few effective policies that could affect improved social mobility in human societies.
When I ask students or friends about social mobility, the impression they usually convey is that of a class system that is strongly inherited over generations. There is a vague notion that we live in a world stratified by timeless elites at the top, a persistent middle class, and a lower class, the genre typically ridiculed on reality TV. University economists know this best, and for decades the data has shown that the economy “constantly changes” family fortunes over time. My students and friends were wrong: the status does not persist in families beyond a few generations. So are university economists right in this characterization?
The short answer is no. With my co-author Greg Clark (UC Davis), we showed that status persists much more deeply over generations than might have been predicted from previous studies. We live in a world where social class is highly inherited. Our analysis uses surnames to track the elites of English society at different points in time and measure how quickly their offspring have a level of education or wealth indistinguishable from that of the general population. In other words, how quickly do elite bloodlines “regress to the mean”. Economists can measure the rate of regression using a simple number. The ‘intergenerational correlation’ is delimited by zero (complete equality of economic opportunity) and one (status is perfectly inherited and the offspring of the rich remain rich until the end of time).
Small differences in this number matter a lot. Economists believed that the intergenerational correlation in the real world varied between 0.2 and 0.5. This number is generally estimated from data on the incomes of the father and son. An intergenerational correlation in this range implies that the children and grandchildren of the elites and the socially poor are rapidly reverting to the average in their society, with intergenerational status persisting within families for perhaps 3 to 7 generations. Using surnames, we show that the intergenerational correlation of status is in fact closer to 0.85, which means that the offspring of the rich and the poor will take more than 20 generations, or 600 years, to converge towards the average of the company. Socio-economic status is strongly inherited. In fact, it is as strongly inherited as the height.
Take the example of the Norman conquerors of England in 1066. The Domesday book of 1086 records the surnames of many large landowners. Among the conquerors, many of these surnames derive from their domains of origin in Normandy; names like Baskerville, Darcy, and Talbot. If we look at the student rosters at Oxford and Cambridge universities, we find that Norman names are around 1,500% “over-represented” in 1215, based on what we would expect from their share of the population in England. In 1500, Norman names were still more than 400% over-represented in Oxbridge. In fact, if we look at the Oxford student messaging directory, we see that Norman names are still 28% overrepresented in 2011, almost 950 years after the Battle of Hastings.
Although these Norman names appear to have particularly high persistence in Oxbridge data, we find approximately the same pattern when we examine names from other sources. The rare names of landowners detailed in the Post mortem inquisitions from 1236-1299 and ‘locative’ names, such as Berkeley and Pakenhamindicate the same underlying pattern. All of these name groups suggest an intergenerational correlation in the range of 0.8 to 0.9. This is a much higher persistence than would predict from existing studies.
Closer to our time, we looked at rare groups of surnames from the 1881 census in England and Wales. By taking these families and their descendants, we have collected probate information for over 20,000 deaths from 1858 to 2013. These names include well-known surnames such as Rothschild and Brunel, but are mostly composed of names which do not indicate any status, for example Clagett and Loft. In this analysis, we can include the poor. Probate information details the wealth taxable at death and we use this information to calculate the average wealth of each of the 634 families over five generations from 1858. Again, we find a much higher degree of status rigidity than what economists would generally expect. The intergenerational correlation is in the order of 0.7 to 0.75. The descendants of the 19e the elites of the century are even richer than average today.
Our analyzes of the distribution of surnames over time suggest that institutions play a surprisingly weak role in equalizing opportunities. Social mobility in modern England is not much greater than in pre-industrial times. There appears to be a surprising degree of socio-economic rigidity that is relatively immune to government intervention, such as the massive expansion of state support for education since the end of the 19th century.e century. While individuals may benefit from extraordinary luck, our results suggest that groups of individuals, as revealed by their last names, exhibit high status persistence. The degree of “churning” appears to be remarkably limited.
Nine centuries of data suggests that there are very few effective policies that could affect improved social mobility in human societies. Families are made up of individuals who act to ensure the development of the family. The strong forces of culture, social ties and genetics bind generations together. One possible way to achieve this would be to implement a strict law applying whatever the inverse of perfect associative mating. Another possible policy is to take children away from their parents and have them brought up without any contact with their biological families. I can’t imagine that many voters would enthusiastically support someone who seriously suggests this.
It appears that the popular conception of social mobility is in fact largely correct. Economists painted a far too rosy picture of the world. However, these results are based on correlations over time – they are not fate at the individual level. Individuals have accomplished, are accomplishing, and will continue to accomplish much more than could have been predicted when they were born. Our analysis reveals, in our view, a powerful and consistent social physics operating at the family level in England for most of the last millennium. As long as humans exist, there will be a high level of intergenerational persistence.
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About the Author
Neil cummins is assistant professor of economic history at LSE. You can read more about his research at neilcummins.com