Emigrants tend to be selected – that is, differ in systematic ways from non-migrants. Positive selection is invoked to explain the fact that immigrants tend to report better health than natives in countries of destination despite typically coming from poorer origins. Yet even if migrants are positively selected on average, there is still substantial variation in the degree of selectivity across them; and we expect those who are more positively selected to have better outcomes in a range of dimensions. While earlier work with Understanding Society (Luthra and Platt 2023) showed that these expectations did not hold for educational selectivity, they have not been tested for health.
Following Ferrara et al. (2025), we employ relative height to measure health selection and assess its effects on wages. Relative height within countries is the result of nutritional and health exposures in childhood, that is stable throughout prime adult life, unlike measured health status. It thus offers a stable measure of health selectivity. Using Understanding Society matched to a specially constructed data set of heights for male and female immigrants from different countries and birth cohorts, we estimate immigrants’ relative height. Absolute height is itself associated with better wages across a range of different contexts; but evidence is mixed on whether this is driven by health, prestige or discrimination effects. Relative height, though correlated with absolute height is not identical with it: a relatively tall East Asian immigrant may be shorter than a relatively short Somali immigrant. If the prestige / discrimination effect dominates, absolute height should be more strongly associated with wages; but if the health effect dominates, then relative height should play a stronger role. Our paper thus speaks to debates in both the migration and labour market inequalities literatures.

Co-authors

Dr Alessandro Ferrara, WZB Berlin Social Science Center;

Professor Renee Luthra, University of Essex