Sunday, April 10, 2016
Assortive Marriage in One Generation Produces A Wide Gap in Educational Achievement in the Next
Nicholas Zill, a well-known family researcher, has conducted an interesting study of just how much difference educational sorting among parents makes in the educational achievement of their kids.
"Assortive mating", or the marriage among people of the same class, is increasingly common. Zill found that half of today's young adults had parents of the same educational level as one another, and another 40% had parents who were only one educational level apart.
Assortive marriage also increases the likelihood that there will be a wide gap in the educational achievement of the children. The gap was so large, in fact, that Zill called it a "chasm." On a standardize 8th grade knowledge test, the children of dual graduate-degree parents scored at the 88th percentile, while the children of two high-school dropouts scored at the 20th.
However, this gap does not cumulate forever. Even in one generation we see some regression to the mean - the top group average is lower than if the kids perfectly reproduced the parents, and the bottom group is considerably higher.