Equity is measured by the difference in the index of quality of schools’ educational resources between socio-economically advantaged and disadvantaged schools. * Korea has a negative value (-0.01), which means that disadvantaged schools receive more resources than the advantaged ones. Source: OECD, (2013a), PISA 2012 Results: What Makes Schools Successful (Volume IV): Resources, Policies and Practices, http://dx.doi.org/10.1787/9789264201156-en. The gap in tertiary enrolment rates between students from the highest income quartile and those from other quartiles has widened dramatically since 1996, and the gap between young people from the highest and the lowest income quartiles is especially large (Figure 2.16).