Education data from the Norwegian twin panel reveal no decline in the marital correlation for educational attainment for the past 35 years. Comparable marital correlations are found for British and American samples. A higher marital correlation is obtained for the parents of the Norwegian twins and the parents of their spouses, but this is an artifact. A twin's recall of his/her parents' educational levels is shown, by model fitting, to be biased by his/her own education level. Allowing for this bias reduces our estimate of the parental marital correlation and reduces estimates of the broad heritability of educational attainment from 74-81 to 49-58%. Other, unrelated factors may also be biasing estimates of the similarity of their parents' educational levels by the twins and their spouses.
- assortative mating
- no secular changes