Estimating the effect of mother's schooling on children's schooling using a sample of adoptees

This paper examines the impact of parental
schooling on the child¿s schooling and uses
adoptees to get rid of persistency effects caused
by the parents¿ genes. The results indicate that,
especially for mothers, inherited abilities and
assortative mating play an important role in the
intergenerational transmission of schooling. In
fact, for adoptees I found no treatment effect for
the mother¿s schooling, conditional on her husband¿s
schooling.
It should be noted, however, that the WLS
data on adoptees and their parents do not possess the properties of a clean and well-de¿ ned
experiment, and that obtained results require a
careful interpretation. There are two potential
dangers to an adoption experiment. First, adoptees
and adoptive parents are different from
other children and their parents. This argument
suggests that my maternal schooling estimates
may be biased and suffer from omitted variables,
but I have little indication of what these
might be. The sensitivity analysis ruled out a
number of plausible candidates. Second, adoptees
are not always randomly assigned to their
adoptive parents. This argument suggests that a
portion of what is interpreted as the impact of
the parent¿s schooling may in fact be genetic.
With respect to paternal schooling estimates
there is some merit to this view. However, with
respect to the estimated maternal effect it is not.
Nonrandom assignment and corresponding upward
bias form no danger when interpreting the
absence of maternal schooling effects.
In all, these results, in combination with the
parallel finndings of Behrman and Rosenzweig
(2002) using twins, support the idea that the
positive influence of mother¿s schooling on that
of her child disappears when heritable abilities
and assortative mating are taken into account.