Born to win? The role of circumstances and luck in early childhood health inequalities

This paper measures the degree of inequality of opportunity in birthweight and birthlength for a sample of Irish infants. The sample is partitioned into eight types by mothers’ education and mothers’ smoking status. Stochastic dominance tests reveal the presence of inequality of opportunity but its fraction of total inequality is comparatively small at 1-2%, with the remainder of inequality assigned to random, unobserved factors. These results are robust to finer partitioning of the population and to re-definition of types’ opportunity sets which gives greater weight to inequality at the lower end of the distribution. Analysis of the incidence of low birthweight and short birthlength using measures from the poverty and segregation literature also reveal that incidence is not uniform across type and is consistent with the presence of inequality of opportunity.