Journal article: The colour-blind approach to data collection has long been debated. The lack of ethno-racial information in surveys and administrative data impedes researchers from studying the level of inequality and discrimination against minorities. As an alternative to ethno-racial information, the use of factual information such as parents’ place of birth has been proposed. In this paper, we discuss the colour-blind approach in France and review the evidence of discrimination based on origins. Using the Trajectories and Origins survey, we propose a novel index capturing the degree of individuals’ alterity, and we present evidence that it is associated with a penalty in the labour market. Exploiting this index, we further investigate whether information on parents’ place of birth is valuable and adequate to measure population diversity.