摘要：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.
关键词：inheritance, birth-death processes, cross-sectional data, population genetics
