They also make it clear that disadvantaged schools need more support so they can start regarding ethnic differences as a resource for learning, rather than an obstacle to learning (OECD, 2015b). Identifying the relationship between pre-primary education and later performance in school is challenging, because attendance at pre-school is often correlated with socio-economic advantage. When disadvantaged children enter pre-school, they already lag behind advantaged children because they are likely to have had fewer play opportunities at home to explore patterns, shapes and spatial relations, compare magnitudes, and count objects.