A strong association between incomes across generations—with children from poor families likely to be poor as adults—is frequently considered an indicator of insufficient equality of opportunity. Studies of such “intergenerational persistence,” or lack of intergenerational mobility, measure the strength of the relationship between parents’ socio-economic status and that of their children as adults. However, the association between equality of opportunity and common measures of intergenerational persistence is not as clear-cut as is often assumed. To aid interpretation researchers often compare measures across time and space but must recognize that reliable measurement requires overcoming important data and methodological difficulties.
Intergenerational income elasticity, a measure of inequality transmitted between generations, is related to a well-developed conceptual framework.
Comparisons of intergenerational income persistence across countries, localities, and time reveal settings where intergenerational links are weaker; the impacts of poorly measured parental income on elasticity estimates are clear.
Correlations between positions in the income distribution may be a purer measure of persistence than elasticity; researchers are developing new measures to capture the size and direction of mobility.
Measures of intergenerational persistence across three generations are providing new insights.
Not all mechanisms driving intergenerational persistence are necessarily clearly related to fairness and equality of opportunity.
Data requirements for reliably comparing estimates of intergenerational mobility are stringent, resulting in considerable uncertainty, although the increasing availability of administrative data is leading to a step-change in knowledge.
The properties of new measures of intergenerational persistence are less well understood.