All this said, if one number is to summarize the degree to which inequality
is transmitted across the generations, just as sometimes one number, like a Gini
coefficient, is used to summarize the degree of inequality at a point in time,
then the generational elasticity is an appropriate statistic to use. But this does
not mean that it measures “equality of opportunity” or the even-more-elusive
“American Dream.” Roemer (2004, 2012) and Jencks and Tach (2006), among
others, are clear on this point, emphasizing that in no sense is an intergenerational
elasticity of zero an optimum and noting that making an inference about
equality of opportunity from the degree of intergenerational earnings mobility
requires us to draw a line between differences in circumstances—for which individuals
should in some sense be compensated—and personal choices, for which
they should be responsible.