Intergenerational Mobility and the Informative Content of Surnames

Abstract

We propose an alternative method for measuring intergenerational mobility. Traditional methods based on panel data provide measurements that are scarce, difficult to compare across countries and almost impossible to get across time. In particular this means that we do not know how intergenerational mobility is correlated with growth, income or the degree of inequality. Our proposal is to measure the informative content of surnames in one census. The more information does the surname have on the income of an individual, the more important is background in determining outcomes; and thus, the less mobility there is. The reason for this is that surnames inform on family relationships because the distribution of surnames is necessarily much skewed. A large percentage of the population is bound to have a very unfrequent surname. For them the partition generated by surnames is very informative on family linkages. First, we develop a model whose endogenous variable is the joint distribution of surnames and income. Then we explore the relationship between mobility and the informative content of surnames. We allow for assortative mating to be a determinant of both. Then, we use our methodology to show that in a large Spanish region the informative content of surnames is large and consistent with the model. We also show that it has increased over time, indicating a substantial drop in the degree of mobility. Finally, using the peculiarities of the Spanish surname convention we show that the degree of assortative mating has also increased over time, in such a manner that might explain the decrease in mobility observed. Our method allows us to provide measures of mobility comparable across time. It should also allow us to study other issues related to inheritance.

In the Name of the Son (and the Daughter): Intergenerational Mobility in the United States, 1850 –1940

“…This would push the return to female human capital down. 30 A similar but opposite argument holds if there is a decline in the sex ratio. It follows that historical episodes and trends in fecundity and immigration that affected the sex ratio may help explain differences in the evolution of the father-son and fatherdaughter elasticity over the sample period.…”

In the Name of the Son (and the Daughter): Intergenerational Mobility in the United States, 1850-1930

“…Closely related to our project is the work by Güell et al (2007), who use the informative content of family names to study intergenerational mobility in Spain. They develop a model whose endogenous variable is the joint distribution of surnames and income, and explore the relationship between mobility and the informative content of surnames, allowing for assortative mating to be a determinant of both.…”

References

“…A crude application of the general idea was already applied by Bagues (2005), who exploits the fact that hyphenated double-barrelled surnames are very infrequent in Spain in order to identify potential kinship between two individuals. Indeed, and as pointed out by Güell et al (2007), surnames provide information about kinship because their distribution tends to be very skewed, and thus a large percentage of the population is bound to have an infrequent surname. As shown by Figure 1, over 40% of the Spanish population share a surname with fewer than 10,000 other people.…”

“…However, given the di¢ culty to directly estimate the parameters following standard optimization procedures, mixtures models are typically estimated using expectation-maximization (EM) algorithm, which is an iterative process with two stages. 28 First, the expectation stage allows to calculate, for some guess of the true values of the parameters [ g ], the posterior probability that a given individual belongs to a certain group. In particular, it follows from Bayes'theorem that p(Rjx s ; n R s ; n R s ; g ) and p(Rjx s ; n R s ; n R s ; g ), the probability that a candidate is a relative and a nonrelative respectively, given her surname and our guess for the parameter vector, are calculated as:…”